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Page 1: Dubai Engineering Stander

SPECIFICATION TABLE OF CONTENTS

1.0 GENERAL 1.1 GENERAL INFORMATION

1.1.1 Preamble 1.1.2 Abbreviations 1.1.3 Datum 1.1.4 Right of Way 1.1.5 Geotechnical Information 1.1.6 Interpretation of Drawings 1.1.7 Responsibility of Contractor 1.1.8 Governing Standards 1.1.9 Groundwater levels in Dubai

1.2 SITE OFFICE FOR ENGINEERS REPRESENTATIVE

1.2.1 General 1.2.2 Specific Requirements 1.2.3 Location of Contract Offices sand Other Contract Facilities 1.2.4 Service Authorities

1.3 GENERAL REQUIREMENTS

1.3.1 Materials 1.3.2 Setting-Out the Work 1.3.3 Notice of Operation 1.3.4 Traffic Safety and Control 1.3.5 Access to Private Land 1.3.6 Roads and Site to be Kept Clean 1.3.7 Compensation for Damage to Property 1.3.8 Existing Services 1.3.9 Continuous Working 1.3.10 Temporary Staging for Structures 1.3.11 Water Supply 1.3.12 Filling in Holes and Trenches 1.3.13 Protection of Works from Weather 1.3.14 Keeping the Works Free from Water 1.3.15 Sign Boards 1.3.16 Templates 1.3.17 Assistance to the Engineer 1.3.18 Surveying Equipment

1.3.18.1 Expendable Materials 1.3.19 Laboratory (See Appendix , Part 3 of 3)

1.3.19.1 General 1.3.20 Minimum Test Requirements 1.3.21 Sources of Materials 1.3.22 Programming the Progress of the Works 1.3.23 Progress Reports 1.3.24 Progress Photographs 1.3.25 Flows in Pipelines and at Pumping Stations

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1.3.26 Suppression of Noise 1.3.27 Closing of Roads 1.3.28 NOC from Relevant Authorities

2.0 EARTHWORKS 2.1 CLEARING AND GRUBBING

2.2 REMOVAL OF STRUCTURES AND OBSTRUCTIONS

2.2.1 General 2.2.2 Removal of Pipes

2.3 STRUCTURAL EXCAVATION

2.3.1 General 2.3.2 Pre-Construction and Land Drainage Records 2.3.3 Setting Out 2.3.4 Topsoil and Surfacing Materials 2.3.5 Land Drains 2.3.6 Hand Excavation 2.3.7 Support to Excavations 2.3.8 Dewatering 2.3.9 Formation 2.3.10 Excavation at or Near Roads 2.3.11 Excavation for Structures 2.3.12 Excavation for Pipelines 2.3.13 Excavation for Cable/Ducts 2.3.14 Excavated Material 2.3.15 Replacement of Unsuitable Material 2.3.16 Disposal of Material 2.3.17 Cofferdams

2.4 BACKFILLING EXCAVATIONS

2.4.1 General 2.4.2 Selected Backfill 2.4.3 Special Backfill 2.4.4 Filter Material 2.4.5 Structural and Non-Structural Filling 2.4.6 Backfilling of Trenches for Cables/Ducts

2.5 PROTECTION OF EXISTING SERVICES AND REINSTSATEMENT

2.5.1 General 2.5.2 Reinstatement of Unpaved Land 2.5.3 Reinstatement within Road Corridors 2.5.4 Reinstatement of Other Surfaced Areas 2.5.5 Excavation and Reinstatement in Developed Reservations

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3.0 CONCRETE WORKS 3.1 GENERAL 3.2 MATERIALS

3.2.1 Cement 3.2.1.1 General 3.2.1.2 Ordinary Portland Cement 3.2.1.3 Sulphate Resisting Cement 3.2.1.4 Moderate Sulphate Resisting Cement

3.2.2 Fine Aggregate for Concrete and Mortar 3.2.3 Coarse Aggregate for Concrete 3.2.4 Combined Aggregate 3.2.5 Water

3.2.5.1 General 3.2.5.2 Specific Requirements

3.2.6 Admixtures 3.2.7 Concrete Mix Specification 3.2.8 Cement Mortar and Grout

3.3 MIXING AND TESTING

3.3.1 Samples of Aggregates 3.3.2 Trial Mixes for Concrete 3.3.3 Water/Cement Ratio 3.3.4 Measurement of Ingredients 3.3.5 Mixing Concrete 3.3.6 Re-Mixing Concrete 3.3.7 Concrete Testing

3.3.7.1 General 3.3.7.2 Preliminary Testing 3.3.7.3 Works Testing 3.3.7.4 Workability Testing

3.3.8 Frequency of Testing Aggregate and Concrete 3.4 TRANSPORTING AND PLACING CONCRETE

3.4.1 General Requirements 3.4.2 Placing Concrete in Hot Weather 3.4.3 Placing Concrete in Water (Tremie Concrete) 3.4.4 Blinding Concrete

3.5 COMPACTING CONCRETE

3.4.1 Tamping 3.4.2 Vibrating

3.6 CURING OF CONCRETE 3.7 JOINTS IN CONCRETE 3.7.1 Intervals During Concrete

3.7.2 Construction Joints 3.7.3 Jointing Fresh to Set Concrete

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3.7.4 Expansion Joints 3.7.5 Expansion Joint Filler 3.7.6 Expansion Joint Sealing Compound 3.7.7 Waterstop Across Joints in Concrete Structures

3.8 INSPECTION OF CONCRETE 3.9 FAULTY CONCRETE WORK 3.10 REPAIRS TO CONCRETE 3.11 SUPERVISION OF CONCRETE WORK 3.12 FINISHING OF CONCRETE 3.13 DESIGN AND CONSTRUCTION OF FORMWORK 3.13.1 General

3.13.2 Spacing Blocks and Temporary Construction Ties 3.13.3 Slab Forms 3.13.4 Type of Formwork

3.13.4.1 Exposed Concrete Faces for Bridges 3.13.4.2 Sawn Formwork

3.13.5 Preparation of Formwork for Concreting 3.13.6 Approval of Formwork for Concreting 3.13.7 Removal of Formwork 3.13.8 Concrete Below Ground

3.14 READY MIXED CONCRETE

3.14.1 Compliance with Specification 3.14.2 Pumping Concrete 3.14.3 Field Control 3.14.4 Remixing 3.14.5 Documentation

3.15 REINFORCEMENT STEEL 3.15.1 General 3.15.2 Materials Specifications 3.15.3 Construction of Reinforcement 3.15.3.1 Placing Reinforcement 3.15.3.2 Maintaining Reinforcement in Position

3.15.3.3 Approval of Reinforcement Before Concreting 3.16 PRECAST CONCRETE KERBS, EDGINGS & QUADRANTS 3.17 IN-SITU CONCRTE EDGING

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4.0 PIPES, PIPEWORK, MANHOLES AND CHAMBERS 4.1 PIPE MATERIALS 4.1.1 Pipe Classification and Pressure Ratings 4.1.2 Joint Requirements and Limitations

4.1.2.1 Flexible Joints 4.1.2.2 Flanged Joints 4.1.2.3 Flange Adaptors 4.1.2.4 Bolted Couplings 4.1.2.5 Nuts and Bolts 4.1.2.6 Shipping and Handling

4.1.3 Asbestos Cement Pipes and Fittings 4.1.4 Unplasticised Polyvinyl Chloride Pipes and Fittings (uPVC)

4.1.5 uPVC Pipes for land Drains 4.1.6 Glass Reinforced Pipes and Fittings GRP)

4.1.6.1 General 4.1.6.2 GRP Pipes and fittings for Pumping Stations

and Valve Chambers 4.1.6.3 Factory Testing

4.1.6.4 Installation 4.1.7 Polyethylene Pipes (HDPE or HPPE)

4.1.7.1 General 4.1.7.2 Wall thickness 4.2 STORAGE AND HANDLING OF PIPES

4.2.1 General 4.2.2 Glass Reinforced Plastic Pipes (GRP) 4.2.3 Thermoplastic Pipes

4.3 GRANULAR MATERIAL FOR PIPE BEDDING 4.3.1 Stone for land Drains 4.3.2 Compaction Fraction Test 4.4 CONVENTIONAL (OPEN TRENCH) PIPELINE CONSTRUCTION 4.4.1 General

4.4.2 Nominal Trench Widths 4.4.2.1Pipeline in Wide Trenches

4.4.3 Pipe laying and Jointing 4.4.4 Pipelines in Concrete Cradles and Surrounds 4.4.5 Pipelines on Granular Beds 4.4.6 Placing Surrounds to Pipelines 4.4.6.1 Group A Pipe Materials 4.4.6.2 Group B Pipe Materials 4.4.6.3 Compaction of Pipe Surrounds 4.4.6.4 Pipelines Below Permanent Groundwater Level 4.4.7 Backfilling of Trenches – Pipelines/Structures 4.4.8 Deflection Measurements on Group B Pipelines 4.4.8.1 General 4.4.8.2 Deflection Measurements – GRP Pipes 4.4.8.3 Deflection Measurements – uPVC and other Plastic

Pipes

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4.4.9 Stanks to Pipelines in Granular Bedding 4.4.10 Thrust and Anchor Blocks to Pressure Pipelines 4.4.11 Pipes Protruding from Structures, Concrete Surrounds and Anchor

Blocks 4.4.11.1 Group A Pipe Materials

4.4.11.2 Group B Pipe Materials 4.4.12 Protection of Pipelines and Pipeline Component

4.4.13 Indicator Posts to Pressure Mains 4.4.14 Enclosing Granular or Stone Surround with Geotextile Filter Fabric 4.4.15 Underground Services Warning Tapes 4.5 PIPEWORK WITHIN STRUCTURES 4.6 MANHOLES, CHAMBERS, AND SPECIAL STRUCTURES 4.6.1 General 4.6.2 Construction of Manholes, Chambers and Special Structures 4.6.2.1 Road Gullies

4.6.3 Access Covers, Frames, and Grates 4.6.3.1 General

4.6.3.2 Access Covers and Frames 4.6.3.3 Reinforced Plastic Sealing Plates to Access Covers 4.6.3.4 Road Gully Gratings and Frames 4.7 DUBAI MUNICIPALITY STANDARDS FOR COVERS AND GRATINGS 4.7.1 Approved List of Suppliers

Page 7: Dubai Engineering Stander

5.0 BRICKWORK AND BLOCKWORK 5.1 MATERIALS 5.1.1 Concrete Bricks and Blocks 5.1.2 Bricks 5.1.3 Sand for Mortar

5.1.4 Lime for Mortar 5.2 CONSTRUCTION

5.2.1 General 5.2.2 Engineering Brickwork 5.2.3 Blockwork 5.2.4 Cement Mortar 5.2.5 Cement Lime Mortar 5.2.6 Cement Mortar Rendering

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6.0 INSPECTION AND TESTING OF PIPELINES AND STRUCTURES 6.1 CLEANING AND INSPECTION OF PIPELINES 6.2 TESTING OF PIPELINES

6.2.1 General 6.2.2 Testing of Non-Pressure Pipelines 6.2.3 Testing of Pressure Pipelines

6.3 TESTING OF VALVES 6.4 TESTING OF WATER RETAINING STRUCTURES

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7.0 NOT USED

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8.0 NOT USED

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9.0 CORROSION PROTECTION AND ODOUR CONTROL 9.1 MATERIALS 9.1.1 Corrosive Environments

9.1.2 Paint 9.1.3 Impervious Tanking Membrane 9.1.4 PVC Sheet Lining Material 9.1.5 Reinforced Plastic Liners 9.1.6 In-Situ Laminations 9.1.7 Epoxy Mortar 9.1.8 Bituminous Emulsions 9.1.9 Water Proof Paper 9.1.10 Protective Materials for Wrapping Pipeline Components Suppliers 9.1.11 Approved Paint Suppliers

9.2 INSTALLATION - PROTECTIVE COATINGS AND LINERS TO

CONCRETE 9.2.1 General 9.2.2 Protective Coatings/PVC Liners 9.2.3 Reinforced Plastic Liners 9.2.4 Cutting and Sealing of Reinforced Liners

9.3 ODOUR CONTROL FACILITIES

9.3.1 General 9.3.2 Soil Moisture and pH probes 9.3.3 Activated Carbon Odour Control Filter 9.3.4 Natural Soil Odour Control Filter

9.3.4.1 Materials 9.3.4.2 Installation 9.3.4.3 Monitoring 9.3.4.4 Maintenance 9.3.4.5 Acceptance Test

Page 12: Dubai Engineering Stander

10. BULIDING SPECIFICATIONS 10.1 CONCRETE

10.1.1 Tolerance 10.1.2 Concrete Finish

10.1.3 Construction Bays 10.1.4 Small Precast Items 10.1.5 Cast-in Fixings 10.1.6 Timber Cast-in Fixings

10.2 BRICKWORK AND BLOCKWORK 10.2.1 Damp-Proof Course

10.2.2 Wall Ties 10.2.3 Door and Window Frame Ties 10.2.4 Mastic 10.2.5 Brickwork and Mortar 10.2.6 Cement Mortar 10.2.7 Pointing 10.2.8 Hollow Walls

10.3 ROOFING 10.3.1 Roof Screed

10.3.2 Roof Primer 10.3.3 Waterproofing Membrane 10.3.4 Roof Insulation 10.3.5 Roof Surface 10.3.6 Roof Decking 10.3.7 Fascia Cladding

10.4 JOINERY 10.4.1 Timber-General

10.4.2 Timber-Sizes 10.4.3 Hardwood 10.4.4 Timber Fixing Accessories 10.4.5 Timber Preservative 10.4.6 Ironmongery 10.4.7 Workmanship 10.4.8 Storage 10.4.9 Door Frames 10.4.10 Doors

10.5 METALWORK 10.5.1 Aluminium

10.5.2 Aluminium Louvres 10.5.3 Aluminium Windows 10.5.4 Ironmongery

10.6 PLUMBING 10.6.1 Copper Tubes

10.6.2 Copper Fittings, Waste Pipes, Ball Valves, etc

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10.6.3 UPVC Pressure Pipes and Fittings 10.6.4 Workmanship 10.6.5 Pipework 10.6.6 Copper Tube Fixing 10.6.7 Waste Pipes 10.6.8 Sleeves 10.6.9 Testing 10.6.10 Storage Tanks

10.7 PLASTERWORK & OTHER WALL, FLOOR & CEILING FINISHES 10.7.1 Cement

10.7.2 Lime 10.7.3 Sand 10.7.4 Gypsum Plasters 10.7.5 Plaster Trims 10.7.6 Metal Lathing 10.7.7 Plasticisers 10.7.8 Bonding Agents 10.7.9 Storage 10.7.10 Floor Tiles 10.7.11 Wall Tiles (Internal) 10.7.12 Wall Tiles (External) 10.7.13 Tile Adhesive 10.7.14 Tile Grout 10.7.15 Expansion Joints 10.7.16 Backgrounds 10.7.17 Dissimilar Materials 10.7.18 Hacking 10.7.19 Dubbing Out 10.7.20 Splatterdash or Stipple Coat 10.7.21 Internal Finishes – General 10.7.22 Internal Render 10.7.23 Stucco 10.7.24 External Render

10.8 GLAZING 10.8.1 Glass

10.8.2 Bedding Compound 10.9 PAINTING AND DECORATING 10.9.1 Painting-General

10.9.2 Exterior Stain 10.9.3 Workmanship 10.9.4 Stoppng to Plaster 10.9.5 Steel Priming 10.9.6 Oil-Based Paints 10.9.7 Internal Finish to Walls 10.9.8 Ironmongery

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11.0 Not Used

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12.0 SAFETY PROCEDURES 12.1 GENERAL 12.2 FAMILIARISATION WITH SAFETY PROBLEMS 12.3 SAFETY OFFICER 12.4 SAFE WORKING CONDITIONS AT THE SITE 12.5 SAFETY EQUIPMENT 12.6 SAFETY PROCEDURES

12.6.1 General 12.6.2 Atmosphere Monitoring 12.6.3 Atmosphere Ventilation 12.6.4 Safety Harness 12.6.5 Emergency Breathing Apparatus 12.6.6 Active Confined Space Entry 12.6.7 Washing Facilities 12.6.8 Communication 12.6.9 Lighting

12.7 TRAFFIC CONTROL

Page 16: Dubai Engineering Stander

13.0 Not Used

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14.0 Not Used

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15.0 Not Used

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16.0 MICRO TUNNELING AND PIPE JACKING 16.1 GENERAL

16.1.1 List of Approved Specialist Firms/Sub-Contractors 16.2 SURVEY CONTROL

16.2.1 General 16.2.2 Survey References 16.2.3 Structural Survey 16.2.4 Site Investigations

16.3 GEOTECHNICAL INSTRUMENTATION

16.3.1 Settlement Points 16.3.2 Settlement Anchors 16.3.3 Inclinometers (If required) 16.3.4 Groundwater Observation Wells 16.3.5 Optical Surveys

16.4 DEWATERING

16.4.1 Submittals 16.5 SITE INVESTIGATION 16.6 QUALITY CONTROL 16.7 EQUIPMENT 16.8 EXECUTION 16.9 TESTING 16.10 SAFETY

Page 20: Dubai Engineering Stander

VOLUME 2 SPECFICATIONS

INDEX

PART 2 OF 3: MECHANICAL AND ELECTRICAL WORKS (NOT APPLICABLE) SECTION 17 GENERAL, EELECTRICAL AND MECHANICAL SPECIFICATION SECTION 18 ELECTRICAL SPECIFICATION SECTION 19 MECHANICAL SPECIFICATION SECTION 20 MISCELLANEOUS ELECTRICAL AND MECHANICAL

Page 21: Dubai Engineering Stander

17.0 GENERAL, ELECTRICAL AND MECHANICAL SPECIFICATION 17.1 DRAWINGS AND INFORMATION REQUIRED FOR ELECTRICAL AND

MECHANICAL PLANT 17.2 DRAWINGS AND INFORMATION REQUIRED FOR ELECTRICAL AND

MECHANICAL PLANT 17.2.1 At the start of the Contract

17.2.2 As Built Record Drawing 17.2.3 Prior to Delivery of Plant 17.2.4 Prior to the Issue of the Taking-Over Certificate 17.2.5 During the Maintenance Period

17.3 WORKMANSHIP AND DESIGN OF PLANT 17.4 LUBRICATION OF PLANT 17.5 INITIAL CHARGES OF OILS AND OTHER CONSUMABLES 17.6 SPARES 17.7 TOOLS AND LUBRICANTS 17.8 DELIVERY OF SPARES, TOOLS AND LUBRICANTS 17.9 PPROTECTION AND PACKING FOR SHIPMENT/STORAGE 17.10 AUTOMATIC CONTROL OF PLANT 17.11 INSTRUCTIONS AND TRAINING OF EMPLOYER’S STAFF 17.12 MAINTENANCE OF PLANT 17.13 RETURN TO SITE 17.14 OPERATING AND MAINTENANCE MANUALS

17.14.1 Introduction 17.14.2 General Requirements and Contents

17.15 WORKS TESTING AND INSPECTION OF MANUFACTURED ITEMS 17.16 TESTING AND CERTIFICATION OF MOTORS 17.17 SITE TESTING AND COMMISSIONING OF ELECTRICAL AND

MECHANICAL PLANT 17.18 PLANT SUPPLIERS FOR THIS CONTRACT

17.19 CLIMATE

Page 22: Dubai Engineering Stander

17.20 ELECTRICAL SUPPLY 17.21 DERATING DUE TO THE CLIMATIC CONDITIONS 17.22 TROPICALISATION

17.22.1 General 17.22.2 Metals 17.22.3 Screws, Nuts, Springs, Pivots etc 17.22.4 Wood 17.22.5 Electrical Insulating Materials

17.23 WORK IN DANGEROUS AREAS 17.24 CLASSIFICATION OF HAZARDOUS AREAS 17.25 HEALTH AND SAFETY AT WORK, ETC. ACT 1974 17.26 PROGRESS REPORTS 17.27 QUALITY ASSURANCE STANDARDS 17.28 ADAPTION OF EQUIPMENT 17.29 GUARANTEE 17.30 CO-ORDINATION 17.31 TESTING AND COMMISSIONING PROCEDURES AND DOCUMENTS 17.32 SITE RELIABILITY TRIALS

Page 23: Dubai Engineering Stander

18.0 ELECTRICAL SPECIFICATION 18.1 HV AND LV FACTORY BUILT ASSEMBLIES (F.B.A’S)

18.1.1 Construction 18.1.2 Earthing Bars 18.1.3 Terminals 18.1.4 Busbars 18.1.5 Anti-Condensation Heaters 18.1.6 Indicating Lamps 18.1.7 Indicating Instruments 18.1.8 Motor Starter Isolation 18.1.9 Control Circuit Protection 18.1.10 Rotor Resistances 18.1.11 Socket Outlets 18.1.12 Metering 18.1.13 Labelling 18.1.14 Spares 18.1.15 Future Equipment 18.1.16 Standby Generator Connection 18.1.17 Weatherproof Switchboards 18.1.18 Panel Wiring 18.1.19 Thermal Overload Relays

18.2 CIRCUIT BREAKERS 18.2.1 H.V. Circuit Breakers

18.2.2 Air Break Circuit Breakers 18.2.3 General

18.3 EARTH LEAKAGE CIRCUIT BREAKERS AND SWITCH

DISCONNECTORS 18.4 FUSE-SWITCHES AND FUSE-SWITCH DISCONNECTORS 18.5 FUSE 18.6 CURRENT TRANSFORMERS 18.7 INSTRUMENT VOLTAGE TRANSFORMERS 18.8 ISOLATING TRANSFORMERS 18.9 SELECTOR SWITCHES 18.10 EARTHING 18.11 AC MOTORS

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18.12 MOTOR STARTERS 18.12.1 General 18.12.2 L.V. Starters 18.12.3 H.V. Starters 18.12.4 Slip Ring Rotor Resistance Motor Starters

18.12.4.1 General 18.12.4.2 Floor Standing Units 18.12.4.3 Panel Top Units 18.12.4.4 Integral Panel Units

18.13 MOULDED CASE CIRCUIT BREAKERS (M.C.C.B’S) 18.14 PUMP CONTROLS 18.15 TELEMETRY SYSTEM 18.16 BNATTERY UNITS 18.17 TRANSFORMERS

18.17.1 Standards 18.17.2 Windings 18.17.3 Construction 18.17.4 Fittings

18.18 INSTRUMENTS, INDICATORS AND TRANSMITTERS 18.18.1 General

18.18.2 Instrument Ranges 18.18.3 Field Mounted Instruments 18.18.4 Panel Mounted Instruments 18.18.5 Indicators 18.18.6 Digital Indicators 18.18.7 Integrators 18.18.8 Chart Recorders 18.18.9 Transmitters

18.19 FLOW MEASURING EQUIPMENT

18.19.1 Electro Magnetic Flow Meters 18.19.2 Ultrasonic In-Line Flow Meter 18.19.3 Ultrasonic Open Channel Flow Measuring Equipment 18.19.4 Installation of Ultrasonic Sensors

18.20 LEVEL MEASURING & CONTROL EQUIPMENT

18.20.1 Ultrasonic Level Measuring Equipment 18.20.2 Pressure Level Measuring Equipment 18.20.3 Float Level Control Equipment

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18.21 GENERAL DESCRIPTION OF LIGHTING AND SMALL POWER INSTALLATIONS

18.21.1 Small Power Installations 18.21.2 Lighting Installations 18.21.3 Emergency Lights

18.22 PORTABLE PLANT 18.23 WIRING & CABLING ACCESSORIES

18.23.1 Wiring 18.23.2 Distribution Boards 18.23.3 Socket Outlets 18.23.4 Switches 18.23.5 Lighting Fittings

18.24 CABLES

18.24.1 General 18.24.2 PLYSW & PVC Oversheath Cables 18.24.3 PVC SWA PVC Cables 18.24.4 XLPE PVC SWA PVC Cables 18.24.5 PVC MICC Cables

18.25 CABLING METHODS

18.25.1 General 18.25.2 Conduit System and Associated Cables 18.25.3 Flexible Conduit 18.25.4 Cable Trunking and Associated Cables 18.25.5 Cable Tray

18.26 EARTHING 18.27 ELECTRICAL ACTUATORS 18.28 PLC’s AND MICROPROCESSOR EQUIPMENT

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19.0 MECHANICAL SPECIFICATION 19.1 FINISH 19.2 MATERIALS 19.3 VALVES 19.3.1 General

19.3.2 Gate Valves for Sewage and Related Fluids 19.3.3 Air Valves 19.3.4 Flush Valves 19.3.5 Flap Valves

19.4 PUMPS

19.4.1 General Requirements 19.4.2 Submersible Pumps

19.5 PRESSURE AND COMPOUND GUAGE FOR SEWAGE & SLUDGE 19.6 CENTRIFUGAL FANS (AIR BLOWERS) 19.7 SUPPORTS AND FIXINGS 19.8 SETTING OF MACHINERY 19.9 SUPPORT OF PIPEWORK AND VALVES 19.10 PENSTOCKS

19.10.1 General 19.10.2 Austenitic Ni Resist Iron Penstocks 19.10.3 Stainless Steel Penstock 19.10.4 Plastic Penstock 19.10.5 Actuators

19.11 LIFTING EQUIPMENT

19.11.10. Electrically Operated Traversing Cranes 19.11.11. Manually Operated Lifting Equipment 19.11.12. Lifting Frames 19.11.13. Lifting Davits

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20.0 MISCELLANEOUS ELECTRICAL AND MECHANICAL 20.1 METAL AND PLASTIC MATERIALS 20.1.1 Aluminium Alloy

20.1.2 Steel 20.1.3 Stainless Steel 20.1.4 Reinforced Thermosetting Plastic

20.2 METAL AND PLASTIC PREFABRICATED ITEMS

20.2.1 Ladders 20.2.2 Underground Hydrants and Covers 20.2.3 Open Mesh and Chequer Plate Flooring 20.2.4 Galvanised Steel Guardrailing 20.2.5 Aluminium Guardrailing

20.3 ODOUR CONTROL EQUIPMENT 20.3.1 Design Parameters 20.3.2 Description and Arrangement of Plant

20.3.2.1 General 20.3.2.2 Filter Media Housing 20.3.2.3 Filter Media 20.3.2.4 Extract Fans 20.3.2.5 Differential Pressure Switch 20.3.2.6 H2S Monitor 20.3.2.7 Ductwork 20.3.2.8 Filters 20.3.2.9 Flexible Joints

20.4 VENTILATION

20.4.1 General 20.4.2 Extract Fans 20.4.3 Wet Well Ventilation 20.4.4 Dry Well Ventilation 20.4.5 Fans 20.4.6 Fan Motors 20.4.7 Ducting

20.5 AIR CONDITIONING

20.5.1 Wall Mounted Air Conditioning Units 20.5.2 Centralised Air Conditioning Systems 20.5.3 Split Unit Air Conditioners

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20.6 STANDBY DIESEL GENERATION PLANT 20.6.1 Application 20.6.2 General Description of the Plant

20.6.3 Engine - General 20.6.4 Engine - Lubrication 20.6.5 Engine - Fuel System 20.6.6 Engine - Cooling 20.6.7 Engine - Exhaust System 20.6.8 Engine - Speed Control 20.6.9 Engine - Starting 20.6.10 Engine - Panel 20.6.11 Engine - Safety Devices 20.6.12 Engine - Wiring 20.6.13 Alternator Output 20.6.14 Alternator Construction 20.6.15 Alternator – Terminals 20.6.16 Alternator – Insulation 20.6.17 Alternator – Heaters 20.6.18 Alternator – Waveform, Regulation and Radio Frequency

Interference 20.6.19 Control Panel – Construction 20.6.20 Control Panel – Front Panel 20.6.21 Control Panel – Alarm Annunciator 20.6.22 Control Panels – General 20.6.23 Bulk Fuel Tanks 20.6.24 Transfer Pumps 20.6.25 Fuel System 20.6.26 Enclosure

20.7 FIRE ALARM & EXTINGUISHING SYSTEM

20.7.1 General 20.7.2 Manual Fire alarm Call Point 20.7.3 Optical Smoke Detector 20.7.4 Detector Base 20.7.5 Fire Alarm Panel 20.7.6 Fire Extinguishing Equipment

20.8 ACCESSORIES 20.9 GAS DETECTORS 20.9.1 General

20.9.2 Portable Gas Detector 20.10 SURGE

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SECTION 1

GENERAL

1/1

1.1 GENERAL INFORMATION 1.1.1 Preamble These Specifications shall be read in conjunction with the other documents of the

Tender and Contract Documents and Drawings. The Contractor shall comply with all the provisions contained within these Documents. The Contractor shall take note of the Appendices contained in Part 3 of 3 of these Specifications. Where items in Part 1 of 3 of the Specifications are also covered in the Appendices the requirements of the Appendices shall take precedence.

Works shall also comply with Dubai Municipality “The Roads General

Specification and DM Advisory Notes, Local and Administrative Order. Any clause in these Specifications which relates to work or materials not required by the Contract shall be deemed not to apply.

In order to avoid needless repetition of such phrases as "to the Engineer" and "by

the Engineer" or "the Engineer's Representative" throughout these Specifications it shall be understood that when an order, instruction, decision, exercise of judgment or other similar act is indicated, such order, instruction, decision, exercise of judgment or other similar action will be issued, given, made or referred to the Engineer or the Engineer's Representative.

1.1.2 Abbreviations In this Contract the following abbreviations have the meanings hereby assigned to

them: "AASHTO" means the specification issued by the American Association of State

Highway and Transportation Officials. "ACI" means the specification issued by the American Concrete Institute. "ASA" means the specification issued by the American Standard Association. "ASTM" means the specification by the American Society for Testing and

Materials. "ANSI" means American National Standards Institute. "BS" means the specification issued by the British Standards Institution. "BS. EN" means European Standards adopted as a British Standard. "CP" means the Code of Practice issued by the BS.

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SECTION 1

GENERAL

1/2

"ISO" means International Standards Organisation. "mm" means millimetre. "cm" means centimetre. "sq. cm, or cm2" means square centimetre. "lin. m" means linear metre. "sq. m, or m2" means square metre. "cu. m, or m3" means cubic metre. "km" means kilometre. "kg" means kilogrammes. "t" means tonne. "gal" means U.S. gallon. "ml" means millilitre. "l" means litre. "U S G" means U.S. gauge. "No." means Number. Where no units are quoted for a figure the relevant "System International" (SI) unit

should be assumed. 1.1.3 Datum The levels shown on the Drawings are referred to a series of bench-marks, located

throughout the area of the project, and whose positions and values are shown on the Drawings. In the event of any such bench-mark having become obliterated, the Contractor shall make his own arrangements to ensure that the works are constructed to the levels shown on the Drawings or as amended by the Engineer, and if it is found necessary to cover or destroy any of such indicated bench-marks the Contractor shall transfer the level of such bench-marks to other approved fixed points, which shall then be surveyed and marked on the Drawings. The survey

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station details obtained by the Contractor from the Dubai Municipality Survey Section shall be at Contractor’s cost.

1.1.4 Right of Way The Contractor shall make all the necessary arrangements for any land required for

working areas outside the right of way, including payment when necessary, and the Employer does not accept any liability in connection with such land. This includes land for compounds, temporary roads, detours, diversions and stock piling materials.

1.1.5 Geotechnical Information Any soils and materials test results and information provided for the Contractor

with the Contract Documents at Tender stage are for his information only. The Contractor shall be deemed to have studied this information during the preparation of his Tender and to have carried out any further tests as he may consider necessary. Any Geotechnical information obtained by the Contractor after conducting any soils investigation either during the tender or construction period shall be sent to DM-DLCD No claims for additional payment will be considered from the Contractor on the grounds that the information is insufficient, incorrect, or misleading.

1.1.6 Interpretation of Drawings The Employer and the Engineer accept no responsibility for any omissions from or

for correctness of the representation of existing features on the Drawings. 1.1.7 Responsibility of Contractor Where the approval of the Engineer is required under these Specifications such

approval shall not relieve the Contractor of his duties, responsibilities or liabilities under the Contract.

1.1.8 Governing Standards “Wherever in the specification” tests on completed works and construction control

tests are called for or implied, they shall be carried out according to, and the materials shall comply with, the requirements of the specification (latest edition) with the priority of latest edition, of standards shall be as follows:

a. UAE and DM standards b. International standards such as ISO c. National standards such as BSI and DIN

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d. Others as stated in this specification such as ASTM, etc

The Contractor shall provided for the exclusive use of the Engineer, copies of each and any code of practice, international standards etc. relevant to the works besides all manufacturer’s literature relating to all products to be used in the works, current BSI handbook No 3 and the manufacturer’s instructions for all relevant products, materials, components and installation.

1.1.9 Groundwater Levels in Dubai The Contractor will be deemed to have carried out his own investigations at the

time of Tender to ascertain for himself the nature of the soil conditions and in particular the groundwater levels that will be encountered.

Method statements for dealing with groundwater shall be submitted within three

weeks of the signing of the Contract. 1.1.10 Pollution of Khor Dubai or Arabian Gulf The Contractor shall ensure that no extraneous matter, rubbish or polluting liquid is

deposited or discharged to the Khor Dubai (Creek) or to the foreshore or sea of the Arabian Gulf.

1.2 SITE OFFICE FOR ENGINEER'S REPRESENTATIVE 1.2.1 General The Contractor shall provide, maintain and keep clean temporary site offices with

all associated equipment and services for the exclusive use of the Engineer's Representative and his staff, from commencement until completion of the whole of the Works.

The temporary site offices shall be as-new prefabricated portable unit/s or

alternatively of some other form of weatherproof design and construction to the approval of the Engineer. The building shall be erected on suitable solid foundation.

The offices shall have full partitions and room sizes shall be as shown in the Schedule of Offices. All rooms shall have individual entrance doors.

Corridor and entrance areas shall be additional to the office sizes. The offices shall be air-conditioned with the exception of the Toilet, Shower and

Kitchen areas.

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All rooms shall have glazed windows complete with fly screens and Venetian sun

blinds. Adequate fitted hardware, electrical switches, sockets, lighting, plumbing fittings,

sanitary ware and fittings and fixtures, etc., shall be provided as necessary for the different areas.

The electrical installation shall provide for simultaneous use of all electrical

appliances. The electrical supply shall be 220-250 volts, 50 Hz. The Contractor may either

arrange for a temporary power supply to the offices or alternatively provide and maintain adequate diesel generator sets. All electricity bills shall be paid by the Contractor.

The Contractor may either arrange for a temporary mains water supply or

alternatively provide tankered water supply. All water bills shall be paid by the Contractor.

A minimum of two telephone lines with extensions shall be provided for the offices

along with a third line for an independent telefax facility as shown in the Schedule of Fittings in Appendix C and the Contractor shall pay all installation and rental charges, and call charges, if any, for UAE calls only.

Covered car parking areas of approved construction for five (5) cars shall be

provided adjacent to the offices. The Contractor shall submit any necessary drawings and calculations for the

construction of the offices for the Engineer's approval before commencing construction and shall be responsible for ensuring that the offices are structurally sound. The Engineer may request alterations at this stage. The drawings shall be approved in writing by the Engineer before installation/construction shall commence.

The offices shall be completed and all the equipment provided by the end of the

Mobilisation Period. The Contractor shall provide all items listed in the following Schedule of Offices

and Schedule of Fittings. The Contractor shall obtain the Engineer’s approval for all furniture and equipment proposed.

1.2.2 Specific Requirements

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1. The Contractor shall be responsible for making all arrangements and payments in respects of any land required for the site of the building.

2. The Contractor shall be responsible for the security of the building and its

contents at all times and shall employ watchmen for this purpose.

3. The Contractor shall supply the Consultant's staff with all safety clothing and equipment that shall be necessary for site working such as safety helmets, reflective waistcoats, etc.

4. The building shall be well constructed, burglar proof, mosquito proof and

weatherproof and shall have sufficient doors and glass covered windows for proper light and ventilation. Floors shall be covered with suitable, approved flooring.

5. The Contractor shall retain on site for the exclusive use of the Engineer all

codes and standards referred to in the Specification.

6. The building and services shall be available, fully maintained, until 1 month after the issue of the Taking Over Certificate for the whole of the Works.

7. Following the completion of the whole of the Works, the Contractor shall

remove the offices from the Site and reinstate the area to a natural condition or as directed by the Engineer.

8. The building and all equipment, materials, fittings, etc., shall become the

property of the Contractor after the completion of the Works. 1.2.3 Location of Contract Offices and Other Contract Facilities Within seven days of the date of the Letter of Acceptance issued by the Employer

the Contractor shall submit a plan or plans showing his proposed locations for and details of:

Offices for the Engineer or Engineer's Representatives.

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The Contractor's Site Offices. The Contractor's Stores, Plant and Maintenance Yard, Concrete Batching and

Materials Stockpiling Facilities. Principal routes for heavy plant and lorries. Areas for the temporary storage and permanent dumping of excavated material. The Offices of the Contractor's Project Manager will normally be adjacent to or

close to those of the Engineer for ease of communication. The plan(s) shall be submitted to the Engineer in six (6) copies for approval. Any

reasonable changes or modifications suggested by the Engineer shall be incorporated. All locations shall be subject to the approval of the Employer.

Departures from the approved details shall not be permitted unless written consent

is obtained from the Engineer. 1.2.4 Service Authorities Arrangements for mains water supply, mains electricity supply and telephone

connections shall be made through:- Dubai Electricity and Water Authority Water Division Dubai Electricity and Water Authority Electricity Division Etisalat Emirates Telecommunications Corporation (Dubai) The Service Authorities shall be deemed to also include Departments and/or

Sections of Dubai Municipality and any other public or private authority responsible for services.

1.3 GENERAL REQUIREMENTS 1.3.1 Materials Materials delivered to the Site for the purpose of the Works, shall be accompanied

by a "Certificate of Guarantee" signed by the authorised representative of the manufacturer, which will legally bind the manufacturer to the product delivered.

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Such Certification shall state that the materials specifications and test results are in compliance with the specified requirement of the pertinent designations of the most recent edition of ASTM, BS or any other approved equivalent National Standard unless otherwise directed.

Falsification of such Certificates, Materials, Specifications or Test Results shall be

just cause for the rejection of the materials. All products/materials shall have approved National Certificate of conformance

similar to BSI Quality Kite Mark or National Agrement Certificate such as BBA for non-standard products and systems to be approved by the Engineer and verified by DM-Dubai Central Laboratory

1.3.2 Setting-Out the Work The Contractor shall stake-out the work as to lines and grade in accordance with

the Drawings and secure the approval of the Engineer's Representative before constructing the work. The Engineer's Representative will, if he deems it necessary revise the lines or grades and will require the Contractor to adjust and to stake-out accordingly. The Contractor shall give the Engineer's Representative not less than 24 hours notice of his intention to set out or give levels for any parts of the Works, in order that arrangements may be made for checking. The Contractor shall be responsible for obtaining any setting-out data he may require from Dubai Municipality Survey Section. The Contractor shall also be responsible for obtaining Dubai Municipality Survey Section’s approval on right-of-way. Any costs incurred in this shall be borne by the Contractor.

The Contractor shall, as a requirement of the Contract and without extra charge,

provide all necessary instruments, appliances, surveyor personnel and labour, and any other material or staging, which the Engineer's Representative may require for checking the setting out or for any relevant work to be done. Any marks made by the Engineer's Representative or Contractor shall be carefully preserved and, if destroyed, shall be replaced by the Contractor at his own expense and to the approval of the Engineer. Work shall be suspended for the time necessary for checking the lines and levels on any part of the work, and shall proceed only after approval of measurements.

In the case of any variation from the approved works, the Contractor shall give the

Engineer three copies of cross-sections and profiles of the graphical record or notes and computations of his stake-out as required by the Engineer. At his option he may submit cross-mark on one copy with his approval of the proposed lines of the

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work or his revisions thereof and return it to the Contractor. The Contractor shall resubmit for approval any cross-sections the Engineer may amend.

1.3.3 Notice of Operations The Contractor shall, when required, supply in writing full information regarding

the localities in which the materials are being obtained and in which the work is being prepared.

No permanent work shall be carried out without the consent in writing of the

Engineer's Representative. Full and complete notice, in writing, shall be given 24 hours in advance of the time of the operation in order to make such arrangements as deemed necessary for inspection.

1.3.4 Traffic Safety and Control

1. The Contractor shall provide, erect and maintain such traffic signs, lamps barriers and traffic control signals as may be necessitated by the construction of the Works in accordance with Dubai Municipality and Dubai Traffic Police requirements. The Contractor shall submit proposals for dealing with such situations to the Engineer Dubai Municipality and Dubai Traffic Police for consent. Compliance with this Clause shall not relieve the Contractor of any of his other obligations and liabilities under the Contract.

2. The Contractor shall, after consultation with any statutory or other authority

concerned, submit to the Engineer for his approval a programme based on such consultation showing the scheme of traffic management he proposes for carrying out the Works before commencing any work which affects the use of the public highway rights of way or parking areas and thereafter furnish such further details and information as necessitated by the Works or as the Engineer may require.

3. The Contractor shall not commence any work which affects the public

highway until all traffic safety measures necessitated by the work are fully operational.

4. The traffic diversion and signs, lamps, barriers and traffic control signals

shall be in accordance with the requirements of Dubai Municipality (also refer to Clause 11.5).

5. Traffic signs shall comply with the requirements of Dubai Municipality. The

flashing rate for flashing lamps shall be within the range 120-150 flashes per minute. The minimum luminous intensity of the lamps shall be 0.5 candela

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for steady lamps, 1.0 candela for ripple lamps at their peak, and 1.5 candela for flashing lamps at their peak.

6. The Contractor shall keep clean and legible at all times all traffic signs,

lamps, barriers and traffic control signals and he shall position, re-position, cover or remove them as necessitated by the progress of the Works.

7. Where road diversions roads are approved these must be maintained at

frequencies to suit the traffic volume using them. A good running surface must be maintained and must at all times be free from ruts and potholes.

8. The Contractor’s attention is drawn to the fact that there are several bus stops

within the site boundary as shown on the key and detailed plans for both sewerage and drainage which must be retained and kept operational unless site works directly affect the bus stop.

9. In the event of any work affecting the bus stop, the Contractor shall liaise

with DM/Public Transport (DM/PT) giving them at least two weeks notice of the following operations with start and end dates:-

a. In the event of any necessary redesign of existing bus stops, provide

temporary alternative arrangements in consultation with DM/PT b. In case of road diversion/closure provide temporary alternative

arrangements in consultation with DM/PT and provide all necessary signing for both buses and pedestrians.

1.3.5 Access to Private Land The Contractor shall give three weeks notice to the owner/occupier before entering

private lands and the Contractor shall not enter on to those lands until given permission by the Engineer.

1.3.6 Roads and Site to be Kept Clean The Contractor shall take great care and all reasonable precautions to ensure that

roads and thoroughfares used by him either for the construction of the Works or for the transport of plant, labour and materials are kept clean during of such construction or transport and in the event of their requiring cleaning in the opinion of the Engineer the Contractor shall take all necessary and immediate steps to clean them.

On completion of dewatering the Contractor shall immediately dismantle and

remove from the Site disused discharge pipes and dewatering points.

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Each individual site of work must be clean during the work and must be thoroughly cleaned up on completion.

1.3.7 Compensation for Damage to Property The Contractor shall reinstate all properties whether public or private affected by

the Works, Temporary Works, constructional plant, labour materials or transport to a condition at least equal to that existing before his first entry on to them.

If in the opinion of the Engineer the Contractor shall have failed to take reasonable

and prompt action to discharge his obligations in the matter of site clearance or reinstatements the Engineer will inform the Contractor in writing of his opinion in which circumstances the Employer reserves the right to carry out the reinstatement himself or to arrange for it to be carried out by others or to make payments to the owners and occupiers in respect of such matters for which the Contractor is responsible. All such costs incurred and payments made will be deducted from any monies due or which shall become due from the Employer to the Contractor.

1.3.8 Existing Services Drains, pipes, cables and similar existing services encountered in the course of the

Works shall be guarded from injury or damage by the Contractor at his own cost so that they may continue to function uninterruptedly to the satisfaction of the owners thereof and the Contractor shall not store materials or otherwise occupy any part of the site in any manner likely to hinder the operations of such owners.

1. The Contractor shall protect and support, during the progress of the Works, all

pipe mains, cable wires and other apparatus which might be endangered by his operations. The approximate positions and alignments of known services are indicated on the Drawings, but no guarantee of exact location can be given, and the Contractor must communicate with the authorities and/or proprietors concerned to locate them exactly, and he shall then prepare shop drawings 1/500 scale for each Utility as directed by the Engineer. When approaching each indicated position, the Contractor shall search, by safe methods which will not endanger the service, to determine its precise position.

2. The Contractor shall make his own arrangement with the owners of the

services and with other persons interested, for any diversions, temporary

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stoppages and reinstatements, and he shall allow in his programme for all such arrangements.

3. If any underground service is encountered unexpectedly, excavation shall

cease, and the Engineer's Representative shall be notified immediately. Emergency work, as necessary, should be put in hand without delay and without prejudice to the indemnity of the Employer.

4. The Contractor shall give notice, in writing, to the Engineer and to the

appropriate service company of all damages to existing services caused by him or by any Sub-Contractor in the course of the Works. He shall be held responsible for any such damage and shall immediately have such damage made good at his own expense and shall relieve the Employer of all claims in respect of any loss or interruption involved.

5. If in the opinion of the Engineer, it is necessary or expedient that any pipe,

drain, ditch, cable or overhead wire (including supports) should be broken out, stopped up, diverted, taken down, or altered, the cost of doing so shall be the responsibility of the Contractor. Such work shall be executed only on the written instruction of the Engineer.

6. All existing sewers, culverts, water courses and drains of every kind and

condition that have been altered, extended or otherwise interfered with either directly or indirectly by the work, or that may by leakage, silting, stopping of free flow or otherwise interfere with or delay the execution of the work, shall be made good, cleaned, placed in working order, supported, maintained, and protected and the Contractor shall provide everything necessary for efficiently dealing with, protecting, pumping or removing, as the case may be, all water, sewage, or spoil therefrom.

1.3.9 Continuous Working If in the opinion of the Engineer it is necessary for the safety of the Works or for

any other reason, the Contractor shall, when so ordered, carry out the Works, or any portion thereof continuously by day and night. The Contractor will be reimbursed the agreed extra costs, provided the necessity for the order is not a result of the Contractor's negligence.

1.3.10 Temporary Staging for Structures Temporary staging shall be provided by the Contractor to enable the construction

operations to be performed in the required sequence. The staging shall be properly designed and constructed for the loads which it will be required to support, and

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complete details of the arrangements proposed shall be submitted to the Engineer for approval.

Such approval, however, will not relieve the Contractor of his responsibility for the

adequacy of the staging. The cost of such staging is to be included in the tendered rates and prices entered in the Bills of Quantities.

1.3.11 Water Supply The Contractor shall carry out an investigation prior to submitting his Tender as to

the availability of water for the purpose of the Works and shall consult and arrange with the appropriate authorities and consider all legal aspects. The Contractor shall be entirely responsible for the supply of sufficient water of the specified quality at all times throughout the Contract, and the costs shall be deemed to be covered in the Contract rates and prices.

1.3.12 Filling in Holes and Trenches The Contractor, immediately on completion of any part of the work, shall, at his

own expense, fill up all holes and trenches which have been made or dug by him and are not part of the Works. Holes, cavities, trenches or depressions shall be backfilled with suitable materials and compacted to the grade required or as directed by the Engineer. The Contractor shall clear away all rubbish and materials that is no longer required for the execution of the work, whether his own or any other party to the satisfaction of the Engineer.

1.3.13 Protection of Works from Weather The Contractor, at his own expense, shall protect all works and materials from

injury by weather. All damage caused by adverse weather conditions, whether by flooding or intense heat or any other weather conditions, shall be rectified by the Contractor at his own expense. Abnormal weather conditions shall not be considered any reason for a claim by the Contractor for compensation for damage.

1.3.14 Keeping the Works Free from Water The Contractor shall at his own expense keep the works at all times well drained

and excavations whether above or below the normal water level of the water table free from storm or percolating water which may accumulate on the Site and which may interfere with progress of construction or has or is likely to have deleterious

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effect on the work in progress or the use thereof, by provision of temporary open drains and sub-soil drains, diversion of ditches and other surface water channel or by pumping or other means as required.

1.3.15 Sign Boards The Contractor shall provide and erect signboards as detailed in the BOQ, at the

Site and at the Offices of the Engineer and the Contractor. Normally signboards will be required on all major road approaches to the Site.

The layout and lettering size and location of all signboards and their siting shall be

subject to the approval of Dubai Municipality. The signboards shall give, in English and Arabic, the name of the Project and the

names, Post Office Box numbers and contact telephone numbers of the Employer, the Engineer and the Contractor. The boards shall be of dimensions as shown on the drawings and shall be of durable construction capable of withstanding the effects of the climate for at least the period of the construction and the Defects Liability Period. The boards shall be mounted on substantial frames.

The signboards shall be periodically cleaned, remain legible and be maintained in a

structurally safe condition throughout the period of construction and Defects Liability Period. Upon issue of the Defects Liability Certificate they shall be removed from the Site within two weeks.

1.3.16 Templates When necessary the Contractor shall provide at his expense sufficient and approved

templates for the purpose of controlling the finished shape of certain work. The templates will be in accordance with the Specifications and Drawings where such are provided.

All templates must be approved and shall be maintained in good order to provide

the section required for the entire works. Templates may be checked from time to time and any deficiencies noted shall be rectified immediately.

The Contractor shall also supply straight edges and lines when required to control

the work. 1.3.17 Assistance to the Engineer

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1. The Contractor shall provide and maintain for the use of the Engineer such

surveying and engineering instruments as the Engineer may require for his duties as detailed in (Clause 1.3.18). The Contractor shall provide the Engineer with all necessary assistance in checking the setting out of the Works and interpreting any information used by the Contractor for this purpose including the sole use of a minimum of three (3) chainmen.

2. The Contractor shall provide the Engineer with all assistance, equipment and

material required to document and record progress of the Works. 3. The Contractor shall provide all assistance, equipment and material required by

the Engineer for all the measurement of the Works for monthly valuation and for the final certificate payment.

4. The Contractor shall be responsible for all follow up and co-ordination with all

the service departments. (Electricity, Water, Drainage, Street Lighting, Telephone, Horticultural, etc.).

5. The Contractor shall provide all unskilled labour and necessary tools as

directed by the Engineer. 6. If at any time before the commencement or during the progress of the work it

appears to the Contractor that for the proper execution of a specified part of the Works, shop drawings are necessary, these drawings shall be established by the Contractor and submitted to the Engineers' Representative for approval. The Engineer's Representative shall have authority to order at any time and the Contractor shall agree to provide any number of shop drawings which, in the opinion of the Engineer's Representative are necessary for the proper execution of a specified work. The Contractor shall not proceed with the above mentioned work until these shop drawings are approved by the Engineer's Representative. The Contractor shall not be entitled to any extra compensation or extension of time for the preparation of the above mentioned drawings.

These details shall be dimensioned in the metric system and shall describe

accurately the method of fabrication, applied finish and sizes of all members and fixings and shall indicate methods of marking of components for site erection.

7. The Engineer shall furnish the Contractor AutoCad diskettes of the original

drawings to be corrected as the Works proceed. The Contractor shall correct where required, prepare and supply the Engineer's Representative the updated transparencies and diskettes for his approval. The diskette copies shall be in

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Microstation DGN format of a standard and detail acceptable to the Dubai Municipality Drainage and Irrigation Department.

Such record Drawings produced by the Contractor shall include but not be

limited to the following information: - Offsets from permanent references such as road edge, road centreline,

kerbline, building line, etc., at suitable intervals as directed by the Engineer, for all services encountered during the Works and during trial trenches including description of offsets..

- Level profiles for all sewerage, drainage, rising mains.

- House connection layout and details to be completed as separate drawings

and included on main sewer layout drawings.

8. The Contractor shall not be entitled to any extra payment or extension of time for the preparation of the above mentioned record drawings.

The Contractor shall at the commencement of works, provide the Engineer's

Representative for his full and exclusive use sufficient number of water, soil, concrete, asphalt, and room thermometers as required by the Engineer.

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1.3.18 Surveying Equipment The equipment required on Site under this Contract shall be to the Engineer's

approval and is as follows:

Table 1-1. Schedule of Equipment Item Description

No. Required

a. Rolling Straight Edge As required b. Electronic total station (TC 1600 or equivalent with data recording facilities) 1

c. Target reflectors with 2 km range 3 d. Automatic level, tripod and staff (NAK 2 or equivalent) 1

e. 2 metre ranging poles 10 f. 30 metre steel tape 2 g. 30 metre fibre tape 2 h. Manhole lifting keys for: heavy duty covers

medium duty covers light duty covers

6 6 6

i. Weatherproof, rubber-cased torches 6 j. Survey arrows, wooden pegs, nails, etc. As required k. Safety helmets As required l. Marking chalk, paint As required m. Copy of all standards referred to in the

Specification

1 n. Polaroid Camera 1

o. 5 metre steel tape 4 p. Hammer 1 kg 2 q. Hammer 3 kg 2 r.

Level books, field books, surveying umbrellas

As required

s. Silica gel bags As required t. Universal straight edge 3 metre with edge

gauge

1 u. 3 metre steel pocket tape graduated in mm 2 v.

Aluminium spirit level 1 metre long with four plumbs and two level tubes

1

w. Scientific electronic calculators Solar power As required

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1.3.18.1 Expendable Materials The Contractor shall provide adequate supplies of expendable materials such as

stationary, pencils, inks, drawing paper, pens, pegs, brushes, paint and other similar items required for the satisfactory completion of survey and as required by the Engineer's Representative.

1.3.19 Laboratory (see Appendix, Part 3 of 3) 1.3.19.1 General Testing of all materials and completed works shall be carried out in accordance

with DM Administrative Decision No. 160/2000.

1.3.20 Minimum Test Requirements The following is the schedule of minimum requirements governing tests of

materials which shall be carried out during the execution of the Works. Should the Engineer's Representative deem it necessary to increase or reduce the number of the following mentioned tests, he shall issue his written instructions to the Contractor as and when required, following due consultation with the Employer.

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Table 1-2. Minimum Test Requirements of Materials

Materials Frequency Relevant Standard Water for concrete

One test for each source and as directed by the Engineer thereafter.

BS 3148

Portland Cement

One bag of cement for quality testing shall be taken from each 1700 bags or fraction thereof for each source or manufacturer. The Engineer may in lieu of this accept a testing certificate.

BS 12 - O.P.C BS 4027 - S.R.C BS 4550

Coarse Aggregate

One sample for quality for Concrete testing shall be taken from each designated source. After approval one sample shall be taken for quality testing from each 1000 m3 when the material is in use. On each sample 2 sets of the required tests should be carried out except sieve analysis which shall be 3 in number.

BS 812

Fine Aggregate

As for Coarse Aggregate for concrete above

BS 812

Bituminous Materials

One sample of each type of material shall be taken for each source or delivery from the manufacturers. Subsequent testing shall be as directed by the Engineer but not less than one sample for each 500 drums (55gal) or equivalent.

BS 3195

Aggregates for Bituminous Mixtures

One sample for quality testing shall be taken from each designated source. After approval one sample shall be taken for quality testing from each 1000 m3 when the material is in use.

ASTM 04.03 BS 812

Mineral Filler for Bituminous Mixtures

One sample for quality testing from each 50 tonnes or fraction thereof.

BS 812

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Table 1-2. Minimum Test Requirements of Materials (Cont’d) Materials Frequency Relevant Standard Bituminous Mixtures

i. One sample of each days production or each 200 tonnes laid or part thereof whichever is greater, shall be taken for quality testing. The sample should be taken from the paving machine after approximately half of any one load has been laid or from the plant.

ii. One core sample for specific gravity testing shall be taken for each 300 lin. m of traffic lane or 2000 m2 or parts thereof for each completed layer of pavement.

BS 598 ASTM D 979 ASTM D 979 T230/T166

Subgrade and/or Embankment

A quality testing procedure (laboratory) for each subgrade material or embankment material shall be carried out for each 1500 m3 of material as follows:- i. Granular Gradation. ii. Atterberg Limits Liquid and Plastic

Limits, Linear Shrinkage iii. Compaction Test Modified Proctor with

compaction curve to optimum moisture content and max. dry density.

iv. C.B.R. at 95% of Modified Proctor density.

After laying and compaction a quality testing procedure on each 1000m2 or part thereof should be carried out as follows:- v. Field density vi. Moisture content if directed by the

Engineer the following tests may also be carried out on the material as laid on site.

vii. Field C.B.R. with a speedy estimate for moisture content and dry unit weight.

ASTM D 979 ASTM D 979 BS 1377 BS 1377 BS 1377 ASTM D 979 ASTM D 2216 ASTM D 4429

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Table 1-2. Minimum Test Requirements of Materials (Cont’d)

Materials Frequency Relevant Standard Sub-bases and Aggregate Road

A quality testing procedure (laboratory) for each sub-base bases. or granular road base material shall be carried out for each source but not exceeding 1000 m3 of material as follows: i. For every completed layer one field

density shall be determined on each 500 m2

ii. Liquid Limit. iii. Plastic Limit. iv. Linear Shrinkage. v. Sand Equivalent. vi. Compaction Test by Dry density moisture

content relationship test method with compaction curve.

vii. CBR at 100% of the Dry density moisture content relationship test. viii. After laying and compaction 3 Nos. field tests shall be followed for every 1000 m2 of each layer of sub-grade and sub-base layers and 2 Nos for every 1000 m2 for all other layers

BS 1377 Part 2 BS 1377 Part 2 BS 1377 Part 2 BS 1377 BS 1377 Part 2 BS 1377 ASTM D1883 BS 1377 BS 1377 Part 2

Reinforcing Steel

Reinforcement steel shall be supplied to site with a manufacturer's test certificate for each load. Where directed testing on any sample of reinforcement for the following types may be required:- i. Steel fabric reinforcement. ii. Mild steel and high yield (hot rolled)

bars. iii. Cold worked steel bars. Chemical Analysis of Steel for carbon content as directed by the Engineer

BS 4483 BS 4449 BS 4482 ASTM relevant standard.

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Table 1-2. Minimum Test Requirements of Materials (Cont’d)

Materials Frequency Relevant Standard Concrete One set of at least 6 cubes (or 4

cylinders) shall be obtained from each 75 m3 or fraction thereof placed in each day or class of concrete. Slump tests and compaction factor tests shall be carried-out at the site of the actual placing of concrete as directed by the Engineer. Preparation of concrete specimens & curing of specimens Minimum cement content of hardened concrete as directed by the Engineer.

BS 1881 BS 1881 ASTM C192 ASTM C1084

Precast Concrete Flexural/transverse strength and water absorption for each supplier of precast kerbs and slabs (2 no. samples). Sub-sequently, on approval of a source or supplier 2 samples will be tested every 2000 lin. m for kerbs and every 2000 m2 for slab tiles.

AASHTO T97 ASTM C78 BS 7263

1.3.21 Sources of Materials The Contractor shall be responsible for obtaining the Approval of the local

Authorities for the sources of materials and he shall have no right to claim for any compensation if he is to pay for the material at its source.

1.3.22 Programming the Progress of the Works A detailed computer-based programme using critical path methods shall be

produced by the Contractor as set out in the Conditions of Contract. This shall include full details of resources and rates of progress. The Engineer may require the Contractor to modify the programme on occasions during the course of the Contract. The Contractor shall work to the latest approved programme at all times.

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In planning his programme the Contractor shall allow reasonable time for the Engineer to confirm setting out details as the Works proceed in accordance with the programme.

The Contractor shall indicate on his programme whether the work is to be carried

out during normal site hours or whether overtime or a shift system is necessary to execute the Works.

The Contractor shall present a weekly summary to the Engineer detailing personnel

, plant materials and equipment orders and shipping movements of same. Before the close of Site on each working day the Contractor shall submit a brief

programme for the following working day stating in which area of the site work will be carried out and the location of plant and labour. The format of the programme shall be agreed with the Engineer. The Contractor shall also submit for the Engineer’s approval a daily record of manpower and plant resources.

1.3.23 Progress Reports The Contractor shall be required to submit to the Engineer weekly and monthly

progress reports on the first day of the week following and the first day of the month following respectively.

Weekly Report The report shall include: the meteorological data; Contractor's plant and labour

returns; a brief summary of work completed. Monthly Report The report shall include: a description of the month's work; details of any problems

relating to the Works; quantities; records of test results; charts illustrating progress in terms of work done against programmed work and the financial status of the Contract including value of works completed, certified and monies received; progress photographs.

1.3.24 Progress Photographs The Contractor shall arrange to take monthly record photographs of the Works in

progress. These photographs shall cover such extent of the Works as the Engineer shall direct. The days upon which the photographs are to be taken shall be decided by the Engineer.

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The Contractor shall provide the Engineer on the last day of each month one set of progress photographs, with dates imprinted on it, which shall comprise the following:

- One colour negative of each photograph for an anticipated maximum of fifty

exposures per month.

- Ten colour prints (294 x 210 mm) of each of a maximum of twenty of the negatives as selected by the Engineer.

The prints are to be processed by an approved professional and shall be in colour

on heavy weight paper with matt finish. The photographs shall have computer produced descriptions incorporated thereon. Each photograph shall be provided with an approved clear plastic cover for binding.

The copyright of all photographs shall be vested in the Employer and the negatives

and prints shall be delivered to the Engineer within 4 days of exposure. 1.3.25 Flows in Pipelines and at Pumping Stations During the execution of the Works the Contractor shall maintain flows in pipelines

and at pumping stations or alternatively provide adequate means of diverting the flows or overpumping of the flows to the satisfaction of the Engineer.

The Contractor should note that the Employer may decide to carry out

overpumping utilising his own plant and resources and the Contractor shall make due allowance for the necessary coordination with the Employer with respect to the Contract programme. Such arrangements will not relieve the Contractor of his obligations for the maintenance of flows and the safety of the Works, personnel and the general public.

No claim for delay or additional work arising from this requirement will be

considered by the Employer. 1.3.26 Suppression of Noise The Contractor shall make every reasonable endeavour both by means of

temporary works and by the use of appropriate plant or silencing devices to ensure that the level of noise resulting from the execution of the Works does not constitute a nuisance.

1.3.27 Closing of Roads

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The Contractor shall give four weeks notice in writing to the Engineer of his

intention to commence work on any public road (which shall include un-made rights-of-way).

The closure of public roads will not be permitted without the written permission of

the Dubai Municipality Roads Department, the Dubai Traffic Police and the Engineer. The Contractor shall submit five (5) copies of his proposals for diverting traffic indicating positions of all signs, cones, lights and anything else which may be necessary. The Contractor shall comply with any Specification for traffic diversion, including surfacing requirements, safety and control laid down by the Authorities in Dubai and shall be responsible for continuous maintenance.

A period of up to 30 days may be required by the Dubai Municipality to process

permits authorising the cutting of existing carriageways. In the event of such permission being refused the Contractor shall have no claim

for any additional payment. No work will be permitted on a public road verge, central reservation or garden

without the SIGNED approval of the respective Authorities copies of which must be submitted to the Engineer before work commences.

The Contractor’s work shall be so arranged that use of the roads affected by the

work shall be restored to the public with the minimum of delay. Laying of the pipelines, backfilling, testing of the pipeline, temporary reinstatement and clearance of the Site shall follow closely behind excavation and the Engineer may limit the length of excavation when necessary.

1.3.28 NOC from Relevant Authorities Not withstanding the requirements of clause 48 of "Conditions of Contract for

Works of Civil Engineering Construction, (Part 1 - General Conditions)" it shall be the Contractor's responsibility to obtain all required No Objection Certificates (NOC) from the relevant Authorities and submit them to the Engineer prior to the Engineer issuing a Taking Over Certificate.

1.3.29 Registration and license of suppliers

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All materials and equipment specified in the Contract documents which are to be incorporated in the works must be obtained from or through a Dubai Emirate supplier and or manufacturer who must be registered and licensed by the Dubai Municipality. If such specified material or equipment is not available from the Dubai Emirate market then any other source is acceptable.

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SECTION 2 - SITE CLEARANCE AND EARTHWORKS 2/1 SITE CLEARANCE DESCRIPTION 2/1.1 This work shall consist of the removal, wholly or in part, and satisfactory disposal of all

buildings, fences, structures, abandoned pipelines, and any other obstruction which are not designated or permitted to remain. It shall also include the salvaging of designated materials and backfilling the resulting trenches, holes and pits.

2/2 SURVEY BEFORE COMMENCEMENT 2/2.1 Prior to starting the site clearance, the Contractor shall carry out a thorough survey of

buildings, structures, fences, trees, etc.. that are to be removed. The Engineer shall be fully informed of the results of this survey and the amount and extent of the demolition and site clearance shall then be agreed with the Engineer.

2/3 DEMOLITION REQUIREMENTS 2/3.1 The Contractor shall in a careful manner, raze, remove and dispose of all buildings and

foundation structures, fences and other obstructions or any portions of which are within the right-of-way, except utilities and those for which other provisions have been made for removal. All designated salvageable material shall be removed, without unnecessary damage, in sections or pieces which may be readily transported, and shall be stored by the Contractor at specified places within the project limits or at designated storage areas as directed by the Engineer. All such salvageable material shall be deemed the property of the Employer.

2/3.2 Foundations of building structures shall generally be removed to a depth of 1 m below

ground level or more if considered necessary by the Engineer. 2/3.3 Where shown on the drawings or where directed by the Engineer, underground

structures, culverts, chambers and foundations other than building foundations shall be removed to such a level as may be indicated on the drawings or directed by the Engineer.

2/3.4 Where directed by the Engineer, the Contractor shall excavate in trench and break out

redundant pipe ducts and surrounds. Where pipes are to be removed and either salvaged or relaid they shall be carefully removed and every precaution taken to avoid breaking or damaging the pipe. The pipes shall be stored when necessary so that there will be no loss or damage before relaying. The Contractor will be required to replace sections lost from storage or damage by negligence or by the use of improper methods in their removal.

2/3.5 Trenches and pits resulting from demolition and site clearance below ground level shall

be properly cleaned out (including pumping) and filled with suitable material and compacted in accordance with the relevant Specifications up to sub-grade level or as otherwise directed by the Engineer.

2/3.6 Where required, the Contractor shall be responsible, prior to demolition, for the

disconnection of all services and clearance from the Dubai Municipality and all Service Authorities.

2/4 GENERAL SITE CLEARANCE 2/4.1 Before commencing any excavation or fill, the area shall be cleared of all trees, stumps,

roots, bushes, vegetation, debris, materials or other obstructions.

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2/4.2 Before removal of any trees or shrubs the Contractor shall obtain written consent from Dubai Municipality Horticultural Section at least two weeks in advance of the planned removal.

2/4.3 The Engineer's approval of any removal of trees and undergrowth must be obtained

before commencement of work. Where directed all bushes, undergrowth, etc. shall be grubbed up and burnt or otherwise disposed of in tips off site (Sub section 2/8). Holes left by stumps or roots shall, within one week, be filled with suitable material, compacted to the Engineer's satisfaction in accordance with Specification Clause 2/17.

2/5 PRESERVATION OF PROPERTY NOT TO BE AFFECTED BY THE WORKS 2/5.1 Attention is directed to the Contractor's obligations under law and under this Contract

with regard to damage, particularly with regard to protection of property, plants and landscape and to responsibility for damage claims.

2/5.2 Existing highways, improvements, facilities, adjacent property, services, and trees and

plants designated for preservation shall be protected from injury or damage which could result from the Contractor's operations.

2/5.3 The form of protection for vegetation within the site shall be of a type and standard

approved by the Dubai Municipality Horticultural Section. 2/6 ROAD SIGNS 2/6.1 All existing road signs, street name plates and the like affected by the works are to be

carefully taken down and stored. Signs to be re-erected shall be cleaned, provided with new fixings where necessary and the posts re-painted in accordance with the Specifications. Redundant signs shall be transported to the stores or depots of relevant Authorities. Any sign, street name plate or the like damaged by the Contractor during his operation shall be repaired or replaced at the Contractor's cost.

2/7 DISPOSAL OF HISTORICAL ARTIFACTS 2/7.1 Where specified, certain materials arising from the site clearance and excavation are to

remain the property of the Employer. All fossils, antiquities and other objects of interest or value which may be found or uncovered on the site shall remain or become the property of the Employer and upon discovery of such an object the Contractor shall forthwith:

a. Use his best endeavours not to disturb or damage the object; b. Cease work which would endanger the object or prevent or impede its removal; c. Inform the Engineer of the discovery and precise location of the object; 2/7.2 The Engineer will issue instructions on the procedure to be adopted which may include

conditions to permit the examination, excavation or removal of the object by a third party.

2/8 DISPOSAL OF SURPLUS MATERIAL 2/8.1 Subject to the provision of Clause 27.1 of the Conditions of Contract Part I and of the

Specification, all materials arising from site clearance which are surplus to or unsuitable for use in the Works shall become the property of the Contractor and shall be disposed of by him either off the Site to an approved tip or if directed or otherwise agreed by the Engineer on the Site in an approved manner.

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2/8.2 Following consultation with Dubai Municipality Public Health Department and in

conformance to the Clause 2/13.3 of the Specification the Contractor shall propose two sites for disposal of unsuitable or surplus material, one of which shall be specified as having priority and which must be filled before the second is used, together with a separate location where hard debris, such as concrete, building rubble, kerbing, road pavement, etc.. shall be disposed of. The Contractor shall seek approval for all the proposed sites from the Dubai Municipality before work commences and disposal at such sites shall be at no extra cost to the Employer.

2/9 EXCAVATION FOR ROAD CONSTRUCTION 2/9.1 This work shall consist of excavating the roadway and borrow pits, removing and

satisfactorily disposing of all materials taken from within the limits of the Work. It shall include all dewatering, excavation, shaping and sloping as necessary for the construction, preparation and completion of all embankments, cuttings, sub-grade, shoulders, slopes, gutters, intersections, approaches and private entrances, as directed, and in conformity to the alignment, grades, and cross- sections shown on the plans or established by the Engineer.

2/10 CLASSIFICATION OF EXCAVATION 2/10.1 Excavated material shall be classified as: - Roadway Excavation. - Borrow Excavation. 2/10.2 Roadway excavation includes all material of whatsoever nature, suitable or unsuitable,

excavated within the limits of the Right of Way for the preparation of the road bed. All such material after deduction for material declared unsuitable by the Engineer, shall be considered to be available for use at locations requiring fill. Roadway excavation shall be sub-classified as Common Excavation and Rock Excavation.

2/10.3 Authority to identify and define the physical characteristics which determine the

classification as "Common Excavation" and "Rock Excavation" in accordance with the intent of the following provisions shall be vested in the Engineer.

2/10.4 Common Excavation - shall consist of the excavation and satisfactory disposal (subject

to Clause 2/15.3) of all soils, certain strata and rock boulders less than one (1) cubic metre in volume. Strata which are altered and weathered and are in place, but which are not firm enough, or in the opinion of the Engineer are not rigid enough to have all the characteristics of rock excavation shall be classified as common excavation.

2/10.5 Rock Excavation - shall consist of the excavation and satisfactory disposal (subject to

Clause 2.15/3) of all unaltered and unweathered firm and rigid igneous, metamorphic and sedimentary solid rock that in the opinion of the Engineer can only be excavated by the use of pneumatic hammers (if excavated by hand) or by bull dozers of over 250 Horse Power equipped with ripper (if excavated mechanically).

2/10.6 Borrow Excavation If the demand for fill material exceeds the quantity of suitable material obtained from the

necessary roadway excavation then suitable material shall be imported to the work site from an approved borrow pit. The excavation, haulage and discharge of material in its final place from a borrow pit shall be classified as Borrow Excavation.

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2/11 EXCAVATION REQUIREMENTS 2/11.1 All materials removed from an excavation shall be used in the formation of the

embankment, shoulders and at such other places as directed, unless it is declared unsuitable and ordered to be sent to tip by the Engineer. No excavated material shall be wasted without written permission from the Engineer, and when such material is to be wasted, it shall hauled to the approved tip (Clause 2/8) or as otherwise directed by the Engineer.

Material suitable for top soil, base material, mineral aggregate or other specified purpose,

encountered in excavation, shall be reserved, if so directed, until it can be placed in its proper position in the roadway. When specified or designated, top soil shall be used as cover on embankment slopes to aid the regrowth of vegetation or other purposes.

2/11.2 Excavated materials wasted by the Contractor without written permission of the Engineer

shall be replaced by the Contractor at his own expense. 2/11.3 During the construction of the roadway, the prepared formation shall be maintained in

such condition that it will be well drained at all times. 2/11.4 Rock, shale and other unsuitable material encountered in cuts shall be excavated to the

lateral limits and depth indicated on the plans or as otherwise directed. Any overbreakage below the depth shown on the plans or as otherwise directed will not be paid for. Backfill of the overbreakage shall be approved suitable material and shall have the same density requirements as specified by the Contract and shall be at the expense of the Contractor. If the backfill of the overbreakage area designated by the Engineer is to be a crushed aggregate concrete or other special aggregate the entire cost of the backfill of the overbreakage shall be at the expense of the Contractor. Undrained pockets shall not be left in the surface of the rock, but they shall be treated as directed by the Engineer.

2/11.5 All slopes, except in solid rock or other material which, in the judgment of the Engineer,

require a modified slope, shall be trimmed accurately to the slopes shown on the cross-section drawings, and care must be exercised that no material shall be loosened beyond the required slopes. Side ditches if required shall be excavated in conformity to line, grade, and cross-section as shown on the Drawings or as directed by the Engineer.

2/11.6 In cut areas, excavation shall be for the full construction width down to 'earthworks

formation level'. For a further depth of 15 cm the existing material shall be scarified, watered as necessary, mixed and compacted to not less than 95% maximum dry density as determined by BS 1377 Part 4 (Method 3.5 or 3.6) latest edition. Field density shall be determined by BS 1377 Part 9 (Method 2.1 or 2.2) latest edition.

2/11.7 The 'improved subgrade layer', using specified imported material, shall then be placed

and compacted to 95% maximum dry density as determined by BS 1377 Part 4 (Method 3.5 or 3.6) latest edition to bring the embankment level up to 'top of improved subgrade level'. Field density shall be determined by BS 1377 Part 9 (Method 2.1 or 2.2) latest edition.

2/11.8 For cuttings 1.5 metres or more in depth the technical requirements, of the Specification

for "Excavation for Structures" (Sub-Section 2/23) shall be complied with. 2/11.9 Where excavation to the finished graded section, that is 'earthworks formation

level',results in a formation or slopes of unsuitable soil, the Engineer may require the Contractor to remove the unsuitable material to a depth directed and backfill to the finished graded section with approved material compacted in accordance with specified requirements for embankment construction. The Contractor shall conduct his operations

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in such a way that the necessary cross-sectional measurements can be taken and agreed with the Engineer before the backfill is placed.

2/11.1 When the Contractor is required or directed to excavate unsuitable material in fill areas, following general clearance of the area (see Specification Sub-Section 2/16 "Embankment Foundation"), the depth to which these unsuitable materials are to be removed will be determined by the Engineer. The Contractor shall so schedule the work so that authorised cross-sections can be taken before and after the material has been removed.

2/11.11 All slopes, lines and grades shall be true, correct, and accurate and according to those on

the drawings or otherwise directed and approved by the Engineer. The 'earthworks formation level' in cuts shall be accurate to the authorised profile grade to plus or minus two (2) centimetres and, for 'top of improved subgrade' level, plus or minus one (1) centimetre. Where discrepancies are found in the Work the Contractor shall make necessary corrections.

2/11.12 The Engineer will check all or any part of the Work, as he deems necessary, to determine

conformance to the lines, grades, elevations and cross-sections. 2/12 BORROW PIT SITE 2/12.1 The Contractor shall obtain approval from the Employer for the location of the borrow pit

site. The Contractor shall be responsible to determine the quantities and quality of the available material in the approved borrow site to meet the requirements of the Contract. When required the borrow area shall be cleared and grubbed in accordance with the requirements of Section 2/1.

2/12.2 The Employer may at any time revoke approval of a borrow site where the Contractor is

obtaining borrow material for the Works. Upon receiving such notice from the Employer, the Contractor shall immediately cease removing material from said borrow site. In the event the Employer revokes approval of the borrow site, the Contractor shall locate a new borrow pit site as specified above.

2/12.3 The Contractor shall not claim any additional payment for any costs by reason of the

necessity of changing borrow site locations due either to the shortage of the supply of borrow material available from the borrow pit site approved by the Employer, or due to the Employer's decision to revoke approval of the borrow site where the Contractor is obtaining borrow material for the Works.

2/12.4 The Contractor shall leave borrow pits in a condition acceptable to the Employer and to

the Engineer. 2/12.5 The Contractor will be solely responsible for ascertaining the location of such approved

borrow areas during the tender preparation stage. Locations, distances to the work site and haulage from such approved borrow areas shall be taken into consideration when preparing the unit tender price for Borrow Excavation.

2/13 DEFINITION, CLASSIFICATION AND GENERAL USE OF EARTHWORKS

MATERIALS The following definitions of earthwork materials shall apply:- 2/13.1 Top Soil shall be fertile, friable soil obtained from well drained arable land and shall be

free draining, non toxic and capable of sustaining healthy plant growth.

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2/13.2 Suitable Material shall comprise all material that is acceptable in accordance with the

Contract and in conformity with Clause 2/13.4 of this Specification for use in the Works. Suitable material for earthworks shall be approved soil with a plasticity index not exceeding 6 obtained from excavations within the Works or from borrow pits approved by the Engineer. It shall not contain an excess of fines (not more than 20% passing Sieve Number 200 as per BS 1377:Part 2:Test 9.2:1990) or in excess of 2% organic material (BS 1377 Part 3). Suitable material for earthworks shall have a soaked CBR value at 95% maximum dry density of not less than 15% when tested according to BS 1377 Part 4 latest edition (method 7). The maximum particle size shall not exceed 63 mm.

2/13.3 Unsuitable Material shall comprise:

- Rock particles exceeding 63 mm in size. - Organic material (BS1377 Part 3 (method 3)) latest edition containing greater than

2% (stumps and other perishable material). - Material susceptible to spontaneous combustion. - Soils of liquid limit (BS 1377 Part 2 (method 4.5)) latest edition exceeding 40%

and/or plasticity index exceeding 6 (BS 1377 Part 2 (method 5)). - Material containing more than 5% of water soluble salts by weight of dry soil as per

BS 1377 Part 3 (Method 8) latest edition methods 7 & 5 for water soluble chloride and sulphate respectively.

- Any other material which the Engineer may deem to be unsuitable for earthworks. 2/13.4 Material for Improved Subgrade layer shall meet the following requirements:-

- Moisture content determination in accordance with BS 1377:Part 2:Test 3.2 latest edition.

- Not more than 20% by weight passing 75 micron to BS 1377:Part 2 latest edition Clause 9.2

- CBR value at 95% maximum dry density (soaked) BS 1377 Part 4 latest edition (Method 3.5 or 3.6) not less than 30% when tested according to BS 1377 (Part 4 method 7) latest edition.

A chemical analysis of the proposed material shall be carried out to satisfy the following requirements:- - The material shall be shown to have an acid soluble sulphate content of 2% or less

and a chloride content in the form of acid soluble chloride of 2% or less by dry weight. The applicable Test methods should be in accordance with BS1377 Part 3 (method 5) latest edition and BS 1377 Part 3 (Method 7) latest edition respectively.

When approved by the Engineer a sulphate content greater than that specified may be acceptable when the carbonate content is in the region of 30 - 40%(BS 1377 Part 3 (method 6)) latest edition. Higher chloride contents may be tolerated provided that the ratio of (carbonate + sulphate) to chloride contents is maintained at approximately 15:1. The moisture content of the compacted material shall not vary by more than + 3% of the optimum moisture content. The material shall possess satisfactory binding characteristics to enable it to be compacted to give a smooth well knit surface as judged by the Engineer.

2/13.5 No excavated suitable material shall be removed from the Site without the Engineer's

written permission. Should the Contractor be permitted to remove suitable material from the site to suit his operational requirements, then he shall make good any consequent deficit filling arising therefrom at his own expense.

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2/14 MAIN PLANT FOR EARTHWORKS CONSTRUCTION 2/14.1 The Contractor shall employ only that plant which is suited to the soils to be handled. He

shall not at any time use plant which damages or reduces the natural strength of the soil either in its in-situ state or during handling and placing or in its final compacted state. Unsuitable or faulty plant shall be removed from the work site and borrow pits at the order of the Engineer.

2/14.2 The plant and equipment used for earthworks construction shall be maintained in good

working condition for the duration of the works. The Contractor shall apply adequate quantities of plant and equipment necessary for the proper execution of the works in an expeditious manner.

2/14.3 Main plant and equipment shall meet the requirements outlined in Clause 1/29 of these

Specifications. 2/15 EMBANKMENT CONSTRUCTION 2/15.1 This work shall consist of constructing roadway embankment with suitable material,

including the preparation of the areas upon which they are to be placed and the placing and compacting of approved material within roadway areas where unsuitable material has been removed. All operations will be performed in accordance with the Specifications and in conformity with the lines, grades, thickness and typical cross-sections shown on the drawings or as established by the Engineer.

2/15.2 Compaction equipment shall conform to the number and type outlined in the Contractor's

detailed programme of work as approved by the Engineer and satisfactory performance shall be the basis for such approval.

2/15.3 All materials derived from excavation shall be used in the embankment unless otherwise

declared unsuitable by the Engineer. 2/15.4 Prior to the commencement of embankment the Contractor shall construct trial

compaction lengths as directed by the Engineer. The soils used in the trials shall be those encountered along the line of the road as approved by the Engineer and/or those originating from the approved borrow pit. The object of the trials is to determine the Field Compactibility of the material with the plant and compaction equipment available with the Contractor. The Engineer may order additional compaction trials when he deems them necessary.

2/15.5 During the construction of embankments the Contractor shall control and direct

construction traffic uniformly over the full width of the embankment. Damage to compacted layers by construction traffic shall be made good by the Contractor at his own expense.

2/15.6 The Contractor shall be responsible for the stability of all embankments and shall replace

all sections which, in the opinion of the Engineer, have been damaged or displaced due to carelessness or neglect on the part of the Contractor, or due to natural causes, such as storms, and not attributable to the unavoidable movement of the natural ground upon which the embankment is made. During construction, the roadway shall be kept shaped and drained at all times. When unsuitable material has been placed in the embankment, its removal shall be at the expense of the Contractor.

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2/16 EMBANKMENT FOUNDATION 2/16.1 All debris, unsuitable material and vegetable matter shall be removed from the surface

upon which the embankment is to be placed and the cleared surface shall be completely broken up by ploughing, scarifying or stepping to a minimum depth of twenty (20) centimetres.

2/16.2 The foundation material shall be adjusted to a moisture content within the moisture range

of + 3% of the optimum moisture content and compacted to not less than ninety-five (95) percent of the Maximum Dry Density as determined by BS 1377 Part 4 (method 3.5 or 3.6) latest edition where the embankment is less than one and a half (1.5 m) metres below subgrade; and compacted to not less than ninety (90) percent where the embankment is more than one and a half (1.5 m) metres below the subgrade.

2/16.3 If the original surface upon which the embankment is to be placed is an old roadbed, the

surface shall be ploughed scarified or broken up, regardless of the height of the embankment to be placed and compacted to a density as determined by the Engineer.

2/16.4 Where an embankment is to be placed on appreciably sloping ground, this surface shall

be benched in steps or trenched in accordance with the Engineer's instructions, including if necessary any under-draining of the affected part of the site.

2/16.5 In circumstances where backfill has to be deposited below standing water. In such cases

the Contractor shall use only an approved granular material of maximum size not greater than 37.5 mm and which on analysis by sieving complies with the requirements of Table 1 below. Such material shall have a "ten percent fines" value of not less than 5 tonnes when tested in accordance with BS 812 Part 111 latest edition and may be deposited below water without the associated use of compaction plant.

TABLE 1 - FREE DRAINING MATERIAL

B.S.SIEVE SIZE % BY WEIGHT PASSING 10 mm Up to 100 5 mm Not more than 85 0.600 mm Not more than 45 0.075 mm Not more than 5 2/17 PLACING AND COMPACTION REQUIREMENTS 2/17.1 Only approved materials shall be used in the construction of embankments. 2/17.2 In the formation of the embankment it is strictly forbidden to push the excavated

materials from the side of the road to the embankment by means of bull dozers. 2/17.3 The fill material shall be delivered and spread in layers not exceeding 25 cm compacted

thickness. The layers of fill shall be graded, levelled, pulverised and mixed, with water added as necessary, to ensure homogeneous conditions through the full depth of the uncompacted layer. For field density testing refer to specification sub-section 2/19.

2/17.4 The compacted density of the fill shall be equal to or greater than 95 (ninety-five) percent

of the Maximum Dry Density as determined by BS 1377 Part 4 (method 3.5 or 3.6) latest edition.

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2/17.5 The material to be imported for the "improved subgrade layer" to be constructed above "earthworks formation level" up to "top of improved subgrade" level as shown on the drawings shall conform to the Specification Sub-Section 2/13 Para 4.

2/17.6 All slopes, lines and grades shall be true, correct, and accurate and according to those

shown on the Drawings or otherwise directed and approved by the Engineer. The "earthworks formation level" in embankments shall be accurate to the authorised profile grade to plus one (1) cm or minus two (2) centimeters and, the 'top of improved subgrade' level, plus or minus one (1) centimetre for 3 locations maximum each 100 m interval. Selected material shall be placed wherever required. Where discrepancies are found in the work the Contractor shall make necessary corrections in a manner approved by the Engineer.

2/18 MOISTURE CONTROL REQUIREMENTS 2/18.1 When the moisture content of the embankment soil does not fall within + 3% of the

optimum moisture content, water shall be added and thoroughly mixed into the soil, by approved methods or the material shall be aerated, whichever is needed to adjust the soil to the proper moisture content.

2/18.2 The amount of water to be added shall be only that amount that will, as determined by the

Engineer by field tests, provide a moisture content in the soil within the required range plus a reasonable amount to compensate for evaporation and other unavoidable losses. Water added in excess of this amount shall be considered as excess water and must be removed by aeration or other suitable means as directed by the Engineer. Satisfactory methods and sufficient equipment shall be used for the furnishing and handling of the water so that there will be no undue loss due to evaporation or waste. If water is added to cut areas or borrow pits, the surface of the areas or pits shall be maintained in such a manner that will prevent undue loss of moisture and segregation.

2/18.3 Use of saline water for earthworks will only be permitted if the percentage of water

soluble salts in the compacted fill does not exceed 3% by weight of dry soil. 2/18.4 For subgrade material moisture range refer to sub-clause 2/13.4. 2/19 TESTING METHODS 2/19.1 A moisture-density test in accordance with BS 1377 Part 4 (method 3.5 or 3.6) latest

edition will be made for each type of soil to be used in the construction of the work to determine the Maximum Dry Density, the Optimum Moisture Content and the Moisture Range required of the soil for satisfactory compaction. The Field Density and actual Moisture Content of the compacted embankment shall be determined by field tests according to BS 1377 Part 9 (method 2.1 or 2.2) latest edition.

2/20 MINIMUM TEST REQUIREMENTS 2/20.1 For the Contractor's general guidance, the following tests will be required prior to use,

and during the construction of the embankment and of the subgrade. EMBANKMENT 2/20.2 Soil samples for Soil classification according to BS 1377:Part II latest edition, laboratory

moisture / density relationship tests and California Bearing Ratio shall be taken prior to use, from any proposed source of material. Each sample shall represent not more than 3,000 Cu.m.

2/20.3 For every completed layer of fill three field density tests shall be performed every 2250

Sq.m. of carriageway or as otherwise directed by the Engineer.

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2/20.4 The Contractor shall carry out any additional compaction tests as ordered by the Engineer

at no additional cost. IMPROVED SUBGRADE 2/20.5 Samples for Soil classification, laboratory moisture density relationship tests and CBR

tests shall be taken prior to use, from any proposed source of material. Each sample shall represent not more than 1,500 Cu.m.

2/20.6 For every completed layer of subgrade, three field density tests shall be performed on

every 1500 sq.m. of carriageway. 2/20.7 The frequency of field compaction tests on the shoulders shall be three every 1500 Sq.m.

constructed or as directed by the Engineer. ROCKFILL 2/20.8 Where embankments to be compacted are formed of material consisting predominantly of

rock fragments of such size that the material cannot be placed in layers of the thickness prescribed without crushing, pulverizing or further breaking down the pieces resulting from normal excavation methods, the material may be placed in the embankment in layers not exceeding a thickness twice the average size of the larger rocks, except that no layer shall exceed 600 mm of loose measurement.

Materials shall be carefully placed so that all large stones will be well distributed and the

voids completely filled with smaller earth, sand or gravel to form a solid embankment. Each layer shall be bladed or levelled with motor grader, bull dozer or similar equipment capable of shifting and forming the layer into a neat and orderly condition. No. rocks larger than eighty (80) mm in any dimension shall be placed in the top one hundred and fifty (150) mm of the embankment unless otherwise noted on the drawings. Conformance to these provisions and compaction in a manner and to a point of consolidation approved by the Engineer will be considered as fulfillment of the requirements for the type of compaction shown on the drawings. Normally, compaction tests will not be performed in these areas but the Engineer reserves the right to test compaction in some other manner if he deems a test necessary to ensure consolidation. Each layer must be approved by the Engineer before the next layer is placed.

Embankments, which are formed of materials that contain rock but also sufficient

compatible material other than rock or other hard material to make rolling feasible, shall be placed and compacted in the manner and to the point of consolidation approved by the Engineer. Moisture shall be added as directed by the Engineer. Compaction tests will be made wherever the Engineer determines they are feasible and necessary. Each layer must be approved by the Engineer before the next layer is placed.

2/21 STABILISING CRUSHED MATERIAL 2/21.1 In the event the foundation on which the embankment or the subgrade materials will be

laid is saturated by water and unstable, the Engineer may decide to lay crushed granular material to stabilise the foundation. Stabilising crushed material shall not be laid directly on ground soil but it shall always be laid on geotextile fabric covering the area to be stabilised as shown on the drawings or directed by the Engineer.

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2/21.2 Such stabilising crushed material when tested in accordance with ASTM C136 shall have

the following gradation:- BS SIEVE % PASSING 50 mm 100 25 mm 80 - 100 12.5 mm 60 - 85 4.75 mm 40 - 70 2.00 mm 20 - 50 850 microns 15 - 25 425 microns 0 - 10 180 microns 0 - 2 2/21.3 The stabilising crushed material shall have the following characteristics:-

- Los Angeles Abrasion (ASTM C131/C535) - Not more than 30% loss (after 500 revolutions)

- Bulk Specific Gravity (ASTM C127) - Not less than 2.65 - Absorption (ASTM C127) - Not more than 2.0%

2/21.4 The stabilising crushed material will be laid in layers of 15 cm and compacted until the

foundation is fully stabilised such that the total thickness of the stabilising layer shall not be less than 30 cm. Only after inspection and approval by the Engineer the Contractor may be allowed to continue the construction of the embankment with other layers of embankment material and/or subgrade material. The Engineer may decide, after having taken the levels of the existing water table in the area, and keeping in consideration the finished road levels, to excavate portions of the foundation saturated by water, disposing of the excavated material, and replacing it with stabilising crushed material.

2/21.5 Before starting any stabilising of the foundation the Engineer will instruct the Contractor

specifying the areas to be stabilised and the final levels to be reached with the stabilising crushed material.

2/22 GEOTEXTILE FABRIC 2/22.1 In areas where the Engineer deems the use of geotextile fabric necessary, the Contractor

shall furnish and place geotextile fabric as specified and as directed by the Engineer.

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2/22.2 The geotextile fabric furnished by the Contractor shall be of an approved grade suitable

for placement over fine sand. The geotextile fabric shall be a woven or non-woven fabric consisting only of long chain polymeric filaments or yarns formed into a stable network such that the filaments or yarns retain their relative position to each other. The fabric shall be stabilised against ultra violet light, inert to commonly uncounted chemicals and chemical properties of the in-situ soil and water, and it shall conform to the following minimum requirements:

Property

Test

Method Unit

(metric) Min.Average Roll Values

(140N)

Grab Tensile Strength

ASTM D

4632

lbs (kN)

120

Grab Tensile Elongation

ASTM D

4632

%

50

Mullen Burst Strength

ASTM D

3786

psi (kPa)

240 (1654)

Puncture Resistance

ASTM D

4833

lbs (kN)

70 (0.31)

Trapezoid Tear Strength

ASTM D

4533

lbs (kN)

50 (0.22)

Permittivity

ASTM D

4491

sec

1.5

Flow Rate

ASTM D

4491

gal/min/ft2

(1/min/m2)

120 (4903)

2/22.3 The surface to receive the geotextile fabric shall be prepared to a relatively smooth

condition free of obtrusions, depressions, and debris. The geotextile fabric shall not be laid in a stretched condition, but shall be laid loosely with the long dimension parallel to the centreline of the roadway. In the event that the width of the proposed area for fabric requires more than one panel width of fabric, the panels shall be overlapped a minimum 15 percent of the panel width. Longitudinal joints in the fabric shall have an overlap of 50cm. To prevent slippage of the overlapping fabric, the areas of overlap shall be stabilized as approved by the Engineer with pins, anchor blocks, or aggregate piles. In the event construction machinery is used to place the fabric, the working platform for the machinery shall be the soil and not the previously laid fabric.

2/22.4 Prior to placement of the granular material (Stabilizing crushed material) the Contractor

shall spread a layer of sand over the geotextile fabric as directed by the Engineer. The aggregate material shall not be dumped directly on the fabric, nor shall haul trucks be run on the fabric. The aggregate shall be spread by a wheeled front-end loader.

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The blade or bucket shall be kept sufficiently high so that the aggregate is not being pulled over the fabric, but being dropped at a minimum height to the satisfaction of the Engineer.

2/22.5 Fabric damaged or displaced before or during installation or during placement of

overlaying aggregate material shall be replaced or repaired to the satisfaction of the Engineer at the Contractor's expense.

2/23 EXCAVATION FOR STRUCTURES 2/23.1 This work shall consist of all excavation for structures, culverts, headwalls, catch basins,

manholes, inlets, and retaining walls and shall include all necessary clearing and grubbing, all necessary bailing, drainage, pumping, sheeting, strutting and the construction of coffer dams or cribs, if found necessary, and their subsequent removal; also the disposal of all material obtained from such excavation and backfilling to the level of the original ground; it shall include the removal of that portion of existing structures below the ground which is necessitated by the construction of the new structure.

2/23.2 Prior to commencing any structural excavation work 1.5 metres or more in depth, the

Contractor shall design and submit to the Engineer for review and approval, within a minimum period of 1 week before the intended commencement date, detailed working drawings of the structural excavation support member materials, sizes, spacing and engineering calculations to validate their design, including the maximum theoretical deflections of the support members. The system shall be designed in such a manner that no raker struts or any other support members extend through surfaces exposed in the finished construction, and no shoring or bracing is placed under permanent structures.

2/23.3 The engineering calculations shall show lateral earth pressure for the full excavation

depths, forces at various stages of support during installation and removal and concrete placement, the anticipated equipment loads, surcharge loads of any description, the maximum design loads to be carried by various members of the support system and strut preload forces.

2/23.4 If the structure support system proposed includes tieback anchors, the Contractor's

submittal drawings shall show the profile of the soil in which each anchor is to be installed, the design load for the full depth of the excavation, the maximum design and proof loads, surcharge loads of any description; equipment loads, forces at various stages, support during installation and removal, and the criteria proposed for deformations under proof loads. Where a proposed system of tieback anchors projects beyond the vertical projection of the Contract limit lines shown on the Drawings on to the adjoining property, the permission of the owner shall be obtained in writing and such permission submitted to the Engineer at the time the shop drawings of the support systems are submitted.

2/23.5 At locations where the excavation extends below the ground water table, a dewatering

system shall be provided which will effectively reduce the hydrostatic pressure and lower the ground water levels below excavation levels, as required for the safe and proper execution of the work and which will result in obtaining a stable, dry subgrade for the execution of subsequent operations. The Contractor shall design dewatering methods and settling basins so that no critical amounts of soil, sand or silt are removed during either the initial operations or the construction operations. Complete working drawings showing the type of dewatering and ground water control system proposed shall be submitted to the Engineer for his review.

2/23.6 The Contractor's submittal drawings shall show the arrangement, location and depths of

the proposed dewatering system if required. A complete description of the equipment and materials to be used and the procedures to be followed shall be shown, together with the standby equipment, standby power supply and the proposed location or locations of

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points of discharge of water. Any required dewatering system design shall also include the measures taken to prevent damage due to settlement of pavement, utilities, sewers, buildings and other structures outside the excavation but within the area affected by the procedures.

2/23.7 The designs of the structure excavation support system and the dewatering systems

specified above shall be prepared by and signed by a Professional Engineer approved by the Engineer specialising in this type of design work. Approval of the designs and shop drawings shall not relieve the Contractor of the adequacy and performance of these temporary works.

2/23.8 Pre-Construction Inspection-prior to the beginning of construction, the Contractor and

the Engineer shall make a detailed inspection of all adjacent buildings, pavements, wells and other structures in order to determine its pre-construction condition and the Contractor shall prepare, for the Engineer's approval, a typed Inspection report of the findings.

2/23.9 The Report shall include photographs, drawings and sketches with levels and dimensions

illustrating the structures condition, noting in particular any existing damage or structural inadequacy. Deficiencies and damage shall be suitably marked on the structure such that it is not permanently defaced.

2/23.10 Three copies of the Report shall be submitted for the approval of the Engineer. Once

approved, five additional copies shall be supplied to the Engineer. 2/23.11 The Contractor shall notify the Engineer sufficiently in advance of the beginning of any

excavation so that cross-sectional elevations and measurements may be taken of the undisturbed ground. The natural ground adjacent to the structure shall not be disturbed without the permission of the Engineer.

2/23.12 Trenches or foundation pits for structures or structure footings shall be excavated to the

lines and grades or elevations shown on the drawings, or as ordered by the Engineer. They shall be of sufficient size to permit the placing of structures or structure footings of the full width and length shown. The elevations of the bottoms of footings, as shown on the Drawing shall be considered as approximate only and the Engineer may order, in writing, such changes in dimensions of elevations of footings as may be deemed necessary, to ensure a satisfactory foundation.

2/23.13 Unless otherwise provided for in the Drawings or Contract Documents or directed by the

Engineer Structural excavation shall be carried out for a width of at least 500 mm beyond the horizontal outside limits of the foundation, footing, box culvert or structural member to which the excavation relates. Concrete blinding or sub- foundations are not to be considered as structure for the purpose of defining such excavation.

2/23.14 If during the progress of the work, loose or improperly compacted soil is encountered

below the structural foundation levels, or adjacent thereof, which is the result of prior removal of utilities or structures, such material shall be completely removed within the limits as directed by the Engineer, backfilled with suitable material and compacted to 95% of the maximum dry density as determined by BS 1377 Part 4 (method 3.5 or 3.6) latest edition. Any previous excavations encountered which would in the opinion of the Engineer be detrimental to load distribution of new foundations to the underlaying soil, shall be excavated and backfilled with Class 25 concrete (clause 4/15).

2/23.15 After each excavation is completed, the Contractor shall notify the Engineer, for approval

of the depth of excavation and the character of the material, prior to further structural works. Any over excavation shall be backfilled with Class 25 concrete (clause 4/15) at the Contractors expense.

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2/23.16 All rock or other hard foundation material shall be cleaned of all loose material and cut to a firm surface, either level, stepped, or serrated as directed by the Engineer. All seams or crevices shall be cleaned and grouted. All loose and disintegrated rock and thin strata shall be removed.

When the footing is to rest on material other than rock, excavation to final grade shall not

be made until just before the footing is to be placed and special care shall be taken not to disturb the excavation. When the foundation material is soft or otherwise unsuitable as determined by the Engineer, the Contractor shall remove the unsuitable material and backfill with approved granular material. This foundation fill shall be placed and compacted in 150mm layers up to the foundation elevation and compacted to 95% of the maximum dry density as determined by BS 1377 Part 4 (method 3.5 or 3.6) latest edition.

The placing of concrete shall follow as closely as practicable the structural excavation. 2/23.17 Control of Ground Water - Prior to the commencement of construction at any particular

location, the Contractor shall install and maintain a system of standpipes and other devices to monitor ground water level in any area which in the opinion of the Engineer is likely to be affected by the dewatering. The number, location and depth of all standpipes shall be to the satisfaction of the Engineer.

- The Contractor shall check ground water levels at weekly or where instructed by the

Engineer, more frequent intervals and submit within 24 hours written reports to the Engineer in a form to be agreed.

- In the case of uncontrolled flow of water into any excavation, the Engineer reserves

the right to order an immediate cessation of work and to order the Contractor to take immediate action to control the inflow of water. Such actions and remedial works shall be to the Engineer's approval.

2/23.18 Notification of Damage- The Contractor shall notify the Engineer immediately of any

movement or any damage not noted in the pre-construction report, to any structure. The Contractor shall immediately cease his construction operations in the vicinity and shall take immediate action to prevent further movement or damage. The Contractor shall keep the Engineer fully informed of all such action.

2/23.19 Remedial and Preventive Works- Should remedial works be necessary due to damage

caused to the structure or should the Engineer direct the contractor to carry out any works necessary to prevent damage to the structure due to the Contractor's construction works, the Contractor will present, without delay, detailed drawings and specifications, as necessary, showing his proposed remedial or preventive works for the Engineer's approval.

In either case the Contractor will suspend all construction activities in the vicinity of the

structure until such time as the remedial or preventive works are carried out to the Engineer's satisfaction at the Contractor's expense.

2/23.20 Post Construction Inspection- On completion of, but prior to final acceptance of the

works, the Contractor and the Engineer shall re-examine the structure to determine any change from the original conditions. The Contractor shall supply to the Engineer for approval five copies of a report describing measures he proposes to take to correct any damage which resulted from the construction of the works. The approved corrective measures shall be carried out by the Contractor at his expense, to the Engineer's satisfaction before final acceptance of the works.

2/23.21 Utilisation of Excavated Materials- All excavated material determined as suitable by

the Engineer, shall be utilised as backfill or roadway fill. The surplus material, shall be disposed of as specified in sub-section 2/8 para 2. Excavated material shall not be

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deposited, at any time, so as to endanger the partly finished structure or cause an obstruction of any kind. All unsuitable material shall be disposed of to approved tips.

2/23.22 Backfill- Excavated areas around structures shall be backfilled with excavated materials

or imported granular material approved by the Engineer. Backfill materials shall be placed in horizontal layers not exceeding 150mm in depth after compaction to 95% of the maximum dry density as determined by BS 1377 Part 4 latest edition (Method 3.5 or 3.6). The field density shall be determined by BS 1377 Part 9 latest edition (Method 2.1 or 2.2). Each layer of material shall be moistened or dried as required to enable thorough compaction as specified. Backfill shall be placed to the original ground level or as indicated on the drawings.

2/23.23 Backfill or embankment shall not be placed behind the walls of concrete structures or

rigid frame structures until the top slab is placed and cured. Backfill and embankment behind abutments when held at the top of the superstructure shall be carried up simultaneously behind opposite abutments. Backfill shall be carried up equally on either sides of box culverts.

2/23.24 For frequency of testing of backfill material refer to sub-section 2/20.

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3.1 GENERAL The prevailing standard for all concrete work shall be BS 8110 and such

amendments as shall be approved by the Engineer in accordance with the CIRIA Guide to Concrete Construction in the Gulf Region.

Concrete work shall consist of furnishing all materials and constructing structures of the forms, shapes and dimensions shown on the Drawings or as directed, using Portland Cement concrete, in accordance with the details shown on the Drawings and these Specifications. Portland Cement concrete shall consist of a mixture of Portland Cement, fine aggregate, coarse aggregate, water and additives when required. The mixture shall be proportioned, mixed, placed and cured in accordance with the requirements of BS 8110: Part 1. Where an additional clause conflicts or is inconsistent with the requirements of BS 8110 the additional clause shall always prevail. The concrete mixes shall be designed mixes for special or ordinary concrete as defined in BS 8110, the design requirements of which are laid down in this Specification.

3.2 MATERIALS

3.2.1 Cement

3.2.1.1 General

Only Sulphate Resisting Cement as specified in Clause 3.2.1.3 shall be used unless otherwise directed. Unless otherwise approved by the Engineer all cements shall comply with the following requirements:- - The acid soluble alkali level measured as Na2O + 0.658 K2O

shall not exceed 0.6% by weight determined by the test method described in BS EN196-21.

- The specific surface (fineness) shall not be greater than 325

m2/Kg and not less than 225 m2/Kg when tested as described in BS EN196-6.

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The cement shall be of approved manufacture and shall be delivered in bags with seals unbroken, or delivered in bulk in approved containers which shall bear the manufacturer’s name, cement type and the date of manufacture. Test certificates from the manufacturers or suppliers shall be submitted for each consignment and shall indicate the results of the tests for compressive strength, setting time, soundness and fineness carried out in accordance with the requirements of the relevant BS or ASTM standards. Further tests may be required by the Engineer after the cement is delivered and stored on the site. The failure of any sample to satisfy the BS or ASTM requirements shall entitle the Engineer to reject the entire consignment from which it was taken. Cement shall be stored immediately upon receipt at site in such a way to keep it away from water and moisture at all times. The Contractor shall provide a method statement for the storage of cement which shall be approved and implemented before any cement is delivered to site. Consignments shall be used in the order in which they were delivered. Any consignment not used within 2 months from the date of manufacture will not be allowed to be used in the Works. No cement from any consignment shall be used in Permanent Works without the approval of the Engineer. Cement which the Engineer considers to have deteriorated in any way shall not be used and shall be removed from site without delay. One brand only of cement as approved by the Engineer shall be used throughout the Works unless otherwise authorised by the Engineer in writing. Differing types of brands shall not be mixed together for use in the Works.

3.2.1.2 Ordinary Portland Cement

Ordinary portland cement (OPC) shall comply with BS 12 or ASTM C150 Type 1. The tricalcium aluminate content shall lie within the range of 4% to 13%. The heat of hydration shall not exceed 290 Kj/Kg at 7 days when tested in accordance with ASTM C186.

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3.2.1.3 Sulphate Resisting Cement

Sulphate resisting cement (SRC) shall comply with BS 4027 or ASTM C150 Type 5. The heat of hydration shall not exceed 290 Kj/Kg at 7 days when tested in accordance with ASTM C186. The strength class shall be ASTM Type V with average compressive strength (N/mm2) for mortar cubes of 15 and 20 at 7 and 28 days respectively.

3.2.1.4 Moderate Sulphate Resisting Cement Moderate sulphate resisting cement (MSRC) shall comply with ASTM

C150 Type 2 but containing not less than 4% and not more than 8% proportion by weight of tricalcium aluminate. In either case the cement shall not contain more than 2.7% proportion by weight of sulphur trioxide.

3.2.2 Fine Aggregate for Concrete and Mortar Fine aggregate for concrete shall consist of natural screened and washed

sand or crushed sand having hard and durable particles, or of other inert materials with similar characteristics. It shall not contain harmful material such as salts, clay lumps, tree roots, shale, iron pyrites, coal, mica, organic matter or any deleterious matter which may attack the reinforcement, in such a form or in sufficient quantity to affect adversely the strength and durability of the concrete. If necessary, the aggregate shall be washed and sieved to remove the deleterious substances. Beach sand shall not be permitted for use in concrete mixes.

The fine aggregate shall comply in all respects with the requirements of

BS 882 and shall also comply with Dubai Municipality Administrative Order No. 143/91. In addition to the above, fine aggregate for concrete shall meet the requirements in Table 3-1.

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Table 3-1. Limits for Properties of Fine Aggregates for Concrete Type Test Method Permissible Limits

1. Magnesium Sulphate

Soundness (5 Cycles) ASTM C88 Max. 12%

2. Clay Lumps and Friable Particles

ASTM C142 Max. 1% by weight

3. Organic Impurities

ASTM C40 Lighter than standard

4. Material Finer than 0.075 mm

ASTM C117 Max. 3%

5. Acid Soluble Chlorides (Cl)

BS 812: Part 117

For reinforced concrete made with: SRC OPC & MSRC For mass concrete made with: SRC OPC & MSRC For prestressed concrete and heat-cured reinforced concrete

Max. 0.03% Max. 0.03% Max. 0.03% Max. 0.03% Max. 0.03%

6. Acid Soluble Sulphates (SO3)

BS 812: Part 118 Max. 0.3% by weight of fine aggregate

7. Water Absorption

ASTM C128 Max. 2.3%

8. Specific Gravity (apparent)

ASTM C128 Min. 2.6

9. Sand Equivalent (when aggregate other than natural sand is approved)

ASTM D2419 Min. 75

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Fine aggregate of fine grading (BS 882) shall not be used. Fine aggregate shall conform to one of the gradings given in Table 3-2 (reproduced from BS 882).

Table 3-2. Grading of Fine Aggregate for Concrete BS 410 Percentage by Weight Passing BS Sieve

Test Sieve (mm)

Coarse Medium

10 100 100 5 100 100

2.36 60 - 100 65 - 100 1.18 30 - 90 45 - 100 0.60 15 - 54 25 - 80 0.30 5 - 40 5 - 48 0.15 0 - 15 0 - 15

3.2.3 Coarse Aggregate for Concrete

Coarse aggregate for concrete shall consist of natural gravel, crushed gravel, or crushed stone, free from coating of clay or other deleterious substances. It shall not contain harmful materials such as salts, iron pyrites, coal, mica, laminated materials, tree roots, shale, or any materials which may attack the reinforcement, in such a form or in sufficient quantity to affect adversely the strength and durability of the concrete. If necessary, coarse aggregate shall be washed to remove deleterious substances.

The coarse aggregate shall comply in all respect with the requirements of BS 882. The coarse aggregate shall also fulfill the requirements in Table 3-3.

Table 3-3. Limits for Properties of Coarse Aggregate for Concrete

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Type

Test Method Permissible Limits

1. Flakiness Index BS 812: Part 105 Max. 25 2. Elongation Index BS 812: Part 105 Max. 25 3. Ten Percent Fines Value or

Impact Value BS 812: Part 111 BS 812: Part 112

Min. 100KN Max. 30%

4. Los Angeles Abrasion ASTM C131/C535

Max. 30%

5. Shell content BS 812: Part 106 Max. 3% by weight

6. Magnesium Sulphate Soundness (5 Cycles)

ASTM C88

Max. 12%

7. Clay Lumps and Friable Particles

ASTM C142 Max. 1% by weight

8. Material Finer than 0.075 mm

ASTM C117 Max. 1%

9. Acid Soluble Chlorides (Cl) For reinforced concrete made with : SRC OPC & MSRC For mass concrete made with:

SRC OPC & MSRC For prestressed concrete and heat-cured reinforced concrete

BS 812: Part 117 Max. 0.01% Max. 0.02% Max. 0.02% Max. 0.04% Max. 0.01%

10. Acid Soluble Sulphates (SO3)

BS 812: Part 118 Max. 0.3% by weight of coarse

Aggregate 11. Water Absorption ASTM C127 Max. 2% 12. Specific Gravity (apparent) ASTM C127 Min. 2.6 13. Drying Shrinkage BS 812: Part 120 Max. 0.05%

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The coarse aggregate shall conform to the gradings given in Table 3-4 in accordance with the nominal size of aggregate specified (reproduced from BS 882). Table 3-4. Gradings of Single Size for Coarse Aggregate

Sieve Size

Percentage by Weight Passing BS Sieve for Nominal Sizes

(mm) 40 mm 20 mm 14 mm 10 mm 50 100 - - -

37.5 85 - 100 100 - - 20.0 0 - 25 85 - 100 100 - 14.0 - - 85 – 100 100 10.0 0 - 5 0 - 25 0 – 50 85 - 100 5.0 - 0 - 5 0 – 10 0 - 25 2.36 - - - 0 - 5

3.2.4 Combined Aggregate Approved coarse aggregate and fine aggregate in each batch of concrete

shall be combined in proportions as specified in BS 882 and as approved by the Engineer. However, in no case shall materials passing the 0.075 mm sieve exceed three (3) percent by weight of the combined aggregate. The combined concrete aggregate gradation used in the work shall be as specified, except when otherwise approved or directed by the Engineer. Changes from one gradation to another shall not be made during the progress of the work unless approved by the Engineer. Naturally occuring sand/gravel mixtures (all in aggregates) shall not be used unless otherwise directed by the Engineer.

3.2.5 Water 3.2.5.1 General

Water for washing aggregate and for mixing or curing of concrete shall

be fresh, clean and substantially free from oil, acids, alkali, sewage, deleterious mineral or organic matter. Water shall comply in all respects with BS 3148. It shall not contain impurities in sufficient amounts to cause discoloration of the concrete.

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All sources of water for use with cement shall be approved by the Engineer. Sources of water shall be maintained at such depth and the water shall be withdrawn in such a manner as to exclude silt, mud, grass and other foreign matter. If at any time during construction the water from an approved source becomes unsatisfactory, the Contractor will be required to provide satisfactory water from some other source.

3.2.5.2 Specific Requirements

Water for washing aggregate and for mixing or curing of concrete shall be tested in accordance with BS and ASTM standards and shall meet the following requirements:

Table 3-5. Chemical Limitations for Mixing Water Parameter Maximum

Concentration Limit

Test Method

1. Chlorides as C1 250 mg/l ASTM D512 2. Sulphates as SO3 350 mg/l ASTM D516 3. Alkali carbonates and bicarbonates

500 mg/l

ASTM D513

4. Total dissolved ions, including 1, 2 & 3 above

2,000 mg/l

BS 1377: Part 3

5. pH Min. 7/max. 9 ASTM D1293 The temperature of water for concrete should not be less than 5° C nor more than 25°C. Water may be cooled to not less than 5°C by the gradual addition of chilled water or ice but on mixing, no ice particles should be present in the mix. Alternatively, flaked ice may be used. The ice to be used should be crushed and should be the product of frozen water which complies with the above requirements.

3.2.6 Admixtures Unless agreed by the Engineer neither admixtures nor cements containing additives shall be used.

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Where the use of admixture had been agreed by the Engineer, they shall conform to the requirements of Type A, Type D, Type F or Type G as specified in ASTM C494 and shall be used in strict accordance with the manufacturer’s instructions. The Contractor shall be entirely responsible for the use of any approved admixtures. Samples of proposed admixtures shall, if required, be submitted to an approved testing authority by the Contractor in order to ascertain its suitability for use in the Works. Approved methods and equipment shall be used for dispensing and incorporating the admixture into the concrete. The dispensing unit shall be designed so that the discharge of the admixture is visible. The cost of such admixtures shall be included in the cost of concrete and no extra payment shall be made if they are used. The proportions of cement, fine aggregate and water shall be determined by the Contractor before concreting commences and submitted together with such test results as may be required to the Engineer for approval and the Contractor shall not commence concreting before such approval is given nor shall he alter or vary in any way the proportion of mix unless he submits fresh test results and mix proportions to the Engineer for approval. The approval by the Engineer of such mix designs does not in any way absolve the Contractor of any of the requirements of the Specifications.

3.2.7 Concrete Mix Specification

The classes of concrete and their respective minimum cement content, consistencies and the minimum required compressive strengths shall be as shown:

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Table 3-6. Concrete Classification and Mixes

Class of Concrete

Comp. Strength (N/mm2)

Slump (mm)

Min.Cement Content (kg/m3)

Max. Free Water/Ceme

nt Ratio

7 days 28 days

A (30/20/SRC)

20 30 25 - 75 310 0.55

B (25/20/SRC)

16 25 25 - 75 275 0.60

C (15/20/SRC)

10 15 25 - 100

250 0.65

The chloride and sulphate levels in the concrete mix shall comply with the requirements of Table 3-7.

Table 3-7. Maximum Limits of Chloride & Sulphate in Concrete Mix

Type of Concrete Chlorides as

C1* (According to BS 1881:Part

124)

Sulphate as SO3*

(According to BS 1881:Part

124) a. For reinforced concrete if made with OPC/MSRC if made with SRC

0.30% 0.06%

3.70% 3.70%

b. For mass concrete if made with OPC/MSRC if made with SRC

0.60% 0.12%

3.70% 3.70%

c. For prestressed concrete and heat-cured reinforced

concrete

0.10% 3.70%

*Maximum limits of chloride and sulphate content as a percentage by weight of cement in the mix.

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The OPC and MSRC cements can also contain chlorides, the relevant standard BS 12 allows up to 0.1% C1. Therefore any chloride content present in the cement has to be taken into account while computing total C1 in the mix. In case the cement contains the maximum limit of 0.1% Cl, then the aggregates, water and admixtures used for prestressed concrete or heat-cured reinforced concrete should be absolutely free of chlorides.

3.2.8 Cement Mortar and Grout

Unless otherwise specified, mortars and grouts shall be composed of Ordinary Portland Cement (satisfying Clause 3.2.1) and sand (satisfying Clause 3.2.2) in the following proportions:-

NOMINAL PROPORTIONS Quality Portland Cement Sand G 1 1 1 G 2 1 2 G 3 1 3

The amount of water (satisfying Clause 3.2.5) added shall just be sufficient to make the mortar or grout workable consistent with its purpose.

3.3 MIXING AND TESTING

3.3.1 Samples of Aggregates

Before any material from a particular source is used, the Contractor shall obtain representative samples of fine and coarse aggregates and carry out the necessary tests and analyses to show that the samples comply with the Specification. During the progress of the Works, the grading and chemical characteristics may be checked at frequent intervals. Sampling of aggregates shall be carried out in accordance with BS 812: Part 101 and Part 102.

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The results of these tests shall be submitted to the Engineer and his approval shall be obtained before any of the material is used in the Works. Part of each sample will be required for concrete trial mixes and part shall be retained for comparison with subsequent deliveries. No deliveries in bulk are to be commenced until such samples are approved by the Engineer as complying with this Specification.

3.3.2 Trial Mixes for Concrete

Following the Engineer's approval of the materials for each class of concrete, the Contractor shall prepare trial mix of each grade of concrete in the presence of the Engineer's Representative. Each trial mix shall comprise not less than 1/3 of a cubic metre of concrete and shall be mixed in an approved type of concrete mixer similar to that which the Contractor propose to employ on the Works. The quantities of all ingredients of trial mix including water shall be carefully determined by weight according to the approved mix design. Each trial mix shall show no tendency to segregate when handled and compacted by the methods by which the Contractor proposes to handle and compact the grade of concrete in the Works and it shall be capable of adequate compaction by such methods.

3.3.3 Water/Cement Ratio

The quantity of water to be added to the cement and aggregates during mixing shall be just sufficient to produce a workable mix to enable it to be well compacted and worked into corners of formwork and around reinforcement. All mixes shall be designed in respect of the proportioning of water so that the Slump Test as carried out according to BS 1881: Part 102 shall be in accordance with the requirements laid out in Clause 3.2.7. Measurement of water on the Site shall take into account the moisture present in the aggregates, and Slump Tests shall be taken frequently to ensure that variations in the moisture content of the aggregate are fully taken into account in determining the amount of water to be added.

3.3.4 Measurement of Ingredients

The aggregates for the concrete shall be measured by weight but measurement by volume may be allowed in special circumstances with the approval of the Engineer.

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When the aggregates are to be measured by weight the weight batching machines shall be of a type approved by the Engineer's Representative. They shall be kept clean and in good condition and adjustment. At intervals as the Engineer's Representative may require, the Contractor shall check the accuracy of each weight-batching machine. When the aggregates are to be measured by volume, the proportions of fine and coarse aggregates shall be measured in well constructed gauge boxes, of dimensions approved by the Engineer's Representative to guarantee that whole multiples of such gauge boxes will ensure the use of one more whole bags or containers of cement and the capacity of the concrete mixer shall be such as to ensure that no splitting of cement bags or containers is required. Gauge boxes shall be properly filled and struck off level, addition of fine aggregates to allow for bulking due to moisture content being made as required. An efficient water measuring device shall be fitted to each concrete mixer. Any cement container shall be such as to contain an accurately weighed amount of cement.

3.3.5 Mixing Concrete

The concrete shall be mixed in a power driven machine of the batch type, no hand mixing being allowed. The mixer shall be large enough to admit the use of 1cement bag or container or whole multiples of bags or containers at a time. The mixing shall continue until there is a thorough distribution of the materials and the mass is uniform in consistency and colour. The period of mixing, judged from the time that all the ingredients including water are in the mixing drum shall be as ordered by the Engineer's Representative but shall not be less than 2 minutes or 20 revolutions of the drum whichever is the longer. Should there be for any reason a stoppage of greater than 30 minutes, the drum or other containers of the mixer shall be thoroughly washed and cleaned before mixing is resumed. On completion of the mixing the concrete shall be discharged onto clean boards or into clean barrows. The method of discharge from the mixer shall be such as to cause no segregation whether partial or otherwise of the concrete materials.

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3.3.6 Re-Mixing Concrete

Concrete which has commenced to set shall not be remixed either with or without additional water and in no case shall such concrete be used in the Works.

3.3.7 Concrete Testing 3.3.7.1 General

The compression tests shall be performed on cubes 150 x 150 x 150 mm as described in BS1881: Part 116. Sampling, making test cubes and curing of cubes shall be in accordance with BS 1881: Parts 101, 108 and 111 respectively. The following methods of testing shall apply to standard concrete cubes.

3.3.7.2 Preliminary Testing After the materials have been approved and at least 10 days before any

concrete is poured, the Contractor shall make 3 Nos. preliminary sets of test cubes. Each set of test cubes shall comprise of three cubes made from a single sample of concrete taken from the point of final discharge of the wet concrete. Each cube shall be made under the Engineer's Representative supervision. Cubes shall be tested as follows: one set shall be tested 7 days after the date of manufacture and one set 28 days after the date of manufacture. The third set will only be tested if the Engineer's Representative wishes to check the results of the tests on either of the other two cubes and shall otherwise be preserved by the Contractor until the end of the Period of Maintenance. Preliminary test cubes shall be made and tested for all grades of concrete and for all proposed variations of quality, quantity or origin of the aggregates and cement.

Should any of the test cubes crushed at 7 days or that crushed at 28 days

fall below the specified requirements and the failure is confirmed by the testing of the third set, the Contractor shall, on the Engineer's Representative's instructions alter the mix design and/or the source of aggregates, cement or water and/or the method of mixing including alteration of the type of mixer. The compressive strength of the concrete cube at 7 days shall be equal to or more than two thirds the required compressive strength at 28 days.

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3.3.7.3 Works Testing During the course of the construction of the Works, the Contractor shall

make test cubes as required by the Engineer's Representative. One set of six cubes will normally be taken from each individual concrete member, e.g. culvert invert, Irish crossings, but additional cubes shall be taken as directed by the Engineer's Representative. Three cubes will be tested at 7 days and three cubes at 28 days as the Engineer's Representative directs. Where the strength of the concrete is shown to be below that specified, the Contractor shall remove and replace at his own expense all concrete from the concerned pour. The Engineer may require the Contractor to cut out defective concrete from the Works at his own expense even though test cubes made from that concrete have not failed.

Durability tests of hardened concrete shall be carried out in addition to

Splitting Tensile Test, Water Absorption Test, ISAT and Depth of Water Penetration test.

3.3.7.4 Workability Testing The Contractor shall carry out slump test in accordance with BS 1881:

Part 102 and/or compacting factor test in accordance with BS 1881: Part 103 at such frequency as the Engineer's Representative considers necessary to ensure that the workability and consistency of the concrete is maintained in accordance with the specified mix or accepted mix design and the trial mix. But in any case workability tests shall be carried out at least once every two hours during which concrete is being mixed.

3.3.8 Frequency of Testing Aggregate and Concrete During the mixing and casting of concrete the frequency of testing for

control purposes shall be as indicated in Table 3-8 or as directed by the Engineer's Representative. No direct payment is made for testing. The price of this work is to be included in the bid prices of concrete.

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Table 3-8. Required Frequency of Testing Aggregates & Concrete Type of Test Frequency

Grading of Fine and Coarse Aggregate; Flakiness and Elongation Index; Aggregate Crushing Value

Once for each source prior to approval and once prior to casting of each lift for any major concrete structure or as directed by the Engineer

Concrete Cube

One set (Min. 6 Cubes) from each mixer for class of concrete and at 10m3. The point of sampling of fresh concrete shall be at delivery into the construction unless otherwise directed by the Engineer. Each set of cubes shall be made from a separate batch.

Compacting Factor Test As directed by the Engineer. Transverse Strength (as per BS 7263 : Part 1)

As directed by the Engineer.

Absorption Requirement(1) (as per BS 1881: Part 122)

As directed by the Engineer.

Slump Test

Once every hour from each mixer or as directed by the Engineer.

Mix Design

Once for each source of aggregate or every combination of sources or as directed by the Engineer.

Portland Cement One 2 Kg sample for quality test shall be taken from each 1,700 bags or equivalent weight. Sampling of cement shall be as per BS EN-7

Water A one gallon sample shall be obtained prior to use from, each source and at least every week for quality testing.

Note: (1) Maximum 2% after 30 minutes

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3.4 TRANSPORTING AND PLACING CONCRETE 3.4.1 General Requirements Concrete shall be taken from the place of mixing to the place of

depositing by approved methods which will prevent the segregation or loss of the ingredients and which are sufficiently rapid to ensure that the concrete does not commence to set before it is compacted in position. The concrete shall be deposited as near as possible to its final position in the Works and shall not be allowed to flow into position. Deposition of the concrete through chutes shall not be permitted and neither shall the concrete be dropped freely from a height exceeding 2.0 m. Pumping concrete through delivery pipes may be permitted but only with the prior approval of the Engineer's Representative.

No concrete shall be placed in a foundation until the extent of excavation and the character of bearing material have been approved and no concrete shall be placed in any structure until the placement of reinforcing steel and the adequacy of the forms and falsework have been approved. The concrete shall be placed in its final positions as soon as possible after it has been mixed, and in any case before the initial set has taken place. The Contractor shall ensure that concrete which has already been placed in position and commenced to set is not disturbed by the placing or compaction of further concrete nearby. All concrete shall be carefully worked around and between reinforcement and all other embedded fittings without such reinforcement or fittings being disturbed. Concrete is to be worked well up against whatever surface it joints. No concrete shall be mixed or placed when the light is insufficient, unless an adequate and approved artificial lighting system is operated and such night work is approved by the Engineer.

3.4.2 Placing Concrete in Hot Weather

Concrete shall only be placed where the general requirements iin regard to ambient and mix temperatures laid down in the CIRIA Guide to Concrete Construction in the Gulf Region are met. The parameters laid down therein shall only be exceeded with the prior written consent of the Engineer.

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Concrete shall not be placed when the shade air temperature exceeds 40° C or during periods of windblown dust or rain. The temperature of batched concrete at time of placing shall not exceed 32°C unless otherwise specified. Measures shall be taken to provide cool concrete and cool concreting conditions in order to reduce workability loss, premature drying of concrete and the development of high temperatures and temperature gradients in placed concrete. Proposed measures must be described in method statements and may include:- (a) Painting white or silver all storage vessels, hoppers, pipes, walls or

roofs which contain or convey aggregates, cement or mixing water. (b) Dampening the forms. (c) Reducing the concrete temperature to the lowest practical level by

procedures such as :- - Shading the aggregate. - Cooling the mixing water before use.

- Screening the mixing plant and transporting vehicles from wind, rain and sun.

(d) Erecting wind breaks and sunshades at the concrete placing

location. (e) Reducing the time between the placing of the concrete and the start

of curing to the minimum possible. (f) Minimizing evaporation (particularly during the first few hours

subsequent to placing the concrete) by suitable means such as applying moisture by fog spraying.

These measures are in addition to those specified for the curing of concrete. In contracts which small structures spread over a large site, such as sewerage contracts, where transportation times could be large, dry mixing of concrete with addition of water immediately prior to placing may be proposed. Method statements for such a proposal must describe methods for accurate batching of water.

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3.4.3 Placing Concrete in Water (Tremie Concrete)

Tremie concrete shall be deposited in water only if specified on the Drawings and/or directed by the Engineer and under the Engineer's supervision. Concrete to be deposited in water shall have the cement content increased by 25% at the Contractor's expense. Concrete shall be carefully placed in a compact mass in the space in which it is to remain by means of a tremie bottom dump bucket or other approved method that does not permit the concrete to fall through the water without adequate protection. The concrete shall not be disturbed after being deposited. No concrete shall be placed in flowing water and forms which are not reasonably watertight shall not be used for holding concrete deposited under water.

3.4.4 Blinding Concrete

Prior to placing any concrete on natural surfaces a blinding layer of Class C concrete shall be laid to a minimum of 75 mm thickness. This blinding shall be suitably curved prior to subsequent concrete placement. The blinding shall be clean and free from any dust or im-purities prior to subsequent concrete placement.

3.5 COMPACTING CONCRETE

3.5.1 Tamping

All concrete shall be thoroughly compacted to the maximum with approved rammers without any segregation in its final position before it commences to set. Care shall be taken to ensure that the use of spade type rammers does not cause segregation of the aggregates and water. Initial compaction of slabs shall be with approved rammers and compaction by a screed board shall be limited to that required for the final shape and finish. During the placing and compaction of reinforced concrete, a competent steel mixer shall be in attendance to adjust and correct if necessary the position of the reinforcement.

3.5.2 Vibrating

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Concrete shall be compacted by vibrating with an approved vibrator. The vibrators shall not be attached to any reinforcement or embedded fitting and where vibrators of the immersion type are used, care shall be taken to ensure that they do not come into contact with the reinforcement or embedded fittings. Freshly placed concrete shall not be vibrated in a manner likely to cause damage to concrete in other parts of the Works which has already taken its initial set. Concrete shall not be vibrated in such a manner and to such an extent as to cause segregation of the constituent materials. If shutter type vibrators are used they shall be augumented by immersion type vibrators if the thickness of the concrete member is more than 15 centimetres.

3.6 CURING OF CONCRETE

All concrete shall be protected from the harmful effects of sunshine, drying winds, rain, flowing water, or other adverse effect. For at least 7 days after placing, the concrete shall be prevented from drying out by being sprayed with fresh clean water and covered with hessian, clean sand or other approved material which shall be kept wet.

Whenever approved by the Engineer, membrane curing of concrete with an approved liquid may be used as an alternative to curing with water except that membrane curing liquid shall not be applied to surfaces of concrete from which the shuttering has been struck, until the concrete has been inspected and approved by the Engineer's Representative.

The concrete curing compound shall comply with the following requirements:

1) Only products which have been proved to be effective through

extensive use shall be proposed and manufacturers’ literature shall include recent test certificates illustrating effective quality control and high curing efficiencies.

2) All materials shall be supplied in the containers marked by the

manufacturer with his name, date of manufacture, shelf life, pot life and instructions for handling and application.

3) The liquid shall contain a white or silver colour pigment in

sufficient quantity to give a uniform colour when applied to the concrete surface.

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4) The liquid shall be of such chemical composition and consistency that it can be applied by an approved mechanical sprayer in fine spray to produce an even, uniform, impervious, continuous film within one hour of application which will not crack, peel or disintegrate within three weeks of application.

The compound shall not be poisonous, odorous or explosive and

shall not react chemically with cement. 5) Curing compounds shall not be applied to surfaces to which further

concrete or a surface finish is subsequently to be bonded unless the approval of the Engineer is obtained to the use of a water soluble type.

The Contractor shall ensure that all concrete is adequately protected

against inclement weather until properly set and shall if necessary provide additional protection to that specified above.

3.7 JOINTS IN CONCRETE

3.7.1 Intervals During Concreting The timetable for the depositing of concrete between construction joints

should be so arranged that no face of concrete shall be left for more than 20 minutes before fresh concrete is deposited against it. Pauses for meals, servicing of machines, changes of shift, etc., and the distribution of concrete among the positions where work may be proceeding simultaneously must be carefully organized to ensure that the above mentioned interval shall not be exceeded.

3.7.2 Construction Joints

Construction joints shall be as shown on the Drawings or as directed by

the Engineer's Representative. If the Contractor wishes to make additional construction joints he shall obtain the prior approval of the Engineer's Representative. Such approval may include the provision and placing of additional reinforcement at the Contractor's expense.

Construction joints shall be formed by inserting temporary vertical stopping-off boards to form tongue and groove joint with the concrete placed subsequently except if separately detailed on the Drawings. Unless otherwise shown on the Drawings construction joints shall be

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located as near as possible to the position of minimum shear and tensile stress in the concrete.

3.7.3 Jointing Fresh to Set Concrete

At a construction joint, the face of the previously placed concrete shall

be cleaned of any skin or laitance or loose material by brushing with a wire brush or other approved method and washing with clean water. Insecurely held aggregate shall be removed. Excess water shall be removed and the surface while still wet shall be covered with 1:2 cement mortar which must be vigorously stippled into the surface by means of a suitable stiff brush, the depositing of the fresh concrete following closely.

3.7.4 Expansion Joints

Expansion joints shall be constructed at positions shown on the

Drawings or as directed by the Engineer and shall be formed according to the instruction and dimensions shown on the Drawings.

Filled expansion joints shall be provided at every 6 m or as shown in

the drawings and/or directed by the Engineer for the kerb and concrete backing. Any excavated surface for the concrete bedding should be watered and compacted to a minimum 95% of optimum density.

3.7.5 Expansion Joint Filler Expansion joint filler shall be composed of approved durable

non-extruding fibrous material suitably impregnated to prevent deterioration. Sheet bitumen fillers will not be accepted. Preformed strips of expansion joint filler shall be of such a nature as not to be permanently deformed or broken by twisting, bending or other normal handling on site. Samples shall be submitted for approval before ordering. The vertical expansion joints in kerbs and parapets shall be formed with approved vertical seal. Such vertical seal shall adhere to the vertical face sealed and shall not flow under maximum local sun temperature nor shall it be sticky to the touch.

1) Expansion joints for precast upstand kerbs shall be at 6 m. 2) For flush kerbs cast in-situ, at 2 m max. 3) For precast slabs, every 4 m min.

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3.7.6 Expansion Joint Sealing Compound

The sealing compound shall be of an approved polysulphide compound,

non-pouring grade for vertical application and pouring grade for horizontal application, as specified in Clause 9.2.1.2 (1) or it may be a rubber-bitumen compound.

The rubber-bitumen compound shall be a flexible weather resistant seal,

slump resistant unaffected by permanent immersion in water, or by alkalis or sulphates. The material shall have a minimum storage life of 12 months in original containers stored in cool dry conditions and a density of 1.30 kg/litre.

The sealing compound shall adhere firmly to the concrete in all weather

conditions. The sealing compound shall not flow either along or down the joint during hot weather. The sealing compound shall be durable and shall not weather beyond the forming of a thin surface skin.

Samples shall be submitted for approval before ordering. Vertical sealer

shall be used with an approved priming compound. Application of the sealing compound shall be strictly in accordance with the Manufacturer's instructions.

3.7.7 Waterstop Across Joints in Concrete Structures Seepage of water through any joints in a water retaining or water

excluding concrete structure shall be prevented by the use of PVC Waterstop or other material as directed and approved by the Engineer. They shall be placed centrally as a water barrier across the designated joint in in-situ concrete structures and cast centrally into the edges of adjacent concrete components.

Waterstop shall be used at all Expansion and Contraction Joints in

concrete structures below water table. For a Construction Joint, requirement of a waterstop shall be indicated in the drawing. The Engineer may also require the Contractor to provide waterstop at any additional Construction Joint approved at his request.

Waterstop shall be extruded from high grade grey PVC Compound. Flat Dumbell plain web waterstop shall be used for a Construction Joint while for an Expansion Joint or a Contraction Joint, a centre bulb waterstop shall be used. The width of the waterstop shall depend upon

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the concrete thickness, the aggregate size and the position of reinforcement. In general, the following shall be taken as a guide to select the width, w, of a waterstop:-

w < t, but w > (6a+j) where, t = concrete thickness a = largest aggregate size j = width of Expansion Joint The following Technical Data shall apply :

Hardness : 42 - 52 BS Softness degrees at 25° C. Tensile strength : 13.8 N/mm2 minimum at 25° C. Elongation at break : 285 % minimum at 25° C.

3.8 INSPECTION OF CONCRETE

The Contractor shall not proceed with the surface finish or making good

of concrete surfaces until he has received the Engineer's Representative's permission to do so and he shall not apply cement slurry or mortar or any other coating to the concrete surfaces from which the shuttering has been struck until the concrete has been inspected and approved by the Engineer's Representative.

3.9 FAULTY CONCRETE WORK

The Contractor shall on the written instruction of the Engineer's

Representative remove and reconstruct any such portion of the work which in the opinion of the Engineer's Representative is unsatisfactory as regards quality of concrete, incorrect dimension of the cast portion, badly placed or insufficient reinforcement, honeycombing or other such cause as shall render the construction not up to the standard required and which in the opinion of the Engineer may affect the strength or durability of the construction.

3.10 REPAIRS TO CONCRETE

The method of repairing and replacing defective concrete which the Contractor proposes to adopt shall be submitted to the Engineer's

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Representative for prior approval and the repair shall be carried out in such manner as the Engineer may direct or approve.

3.11 SUPERVISION OF CONCRETE WORK

Throughout the progress of the concrete work the Contractor shall

employ and provide such supervision as is necessary to ensure

(a) the day to day control of the quality of the concrete and

(b) the mixing, transporting, placing, compacting, curing and protection of the concrete, and

(c) the carrying out of all testing as specified herein and any further

testing which the Engineer's Representative may require, and

(d) the conducting of investigations as the Engineer's Representative may require, and

(e) the preparation of reports and the keeping of such records as the

Engineer's Representative may require.

3.12 FINISHING OF CONCRETE

All concrete surfaces (except top faces of culvert decks) not requiring shuttering shall be trowelled to a smooth dense surface with the minimum of cement and fine particles being brought to the surface and shall be free from irregularities. Top faces of culvert decks shall be carefully screeded and tamped to the required shape and to a dense surface with the minimum amount of cement and fine particles being brought to the surface and should be free from irregularities greater than 3 mm in height or depth. Shuttered surfaces of concrete which will always be in contact with the ground may be cast against sawn timber. All other exposed shuttered surfaces including precast concrete shall be cast against steel, plywood or planed timber formwork and shall be carefully rubbed down with carborundum to remove all imperfections and irregularities. Surfaces which are honeycombed, porous or irregular and which in the opinion of the Engineer's Representative do not comply with the Specification shall be cut out and replaced with sound concrete as directed by the Engineer's Representative. The cost of all normal surface finishes and

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making good shall be deemed to be included in the tendered rate for the concrete.

3.13 DESIGN AND CONSTRUCTION OF FORMWORK

3.13.1 General

Formwork shall in every respect be adapted to the structure and the

required surface finish of the concrete. It shall include all temporary moulds for forming the concrete to the required shape and finish and for the support of such moulds. It shall be fixed in perfect alignment and securely ledged and braced so as to be able to withstand, without displacement deflection or movement of any kind, the weight of the construction and the movement of persons materials and plant. Joints shall be close enough to prevent the leakage of liquid and fine materials from the concrete.

The Engineer's Representative may at any time require the prior submission for approval of the Contractor's proposals for design and construction of formwork including supports. The formwork shall be constructed so as to permit its removal without damage to the concrete.

3.13.2 Spacing Blocks and Temporary Construction Ties

Internal spacing blocks and construction ties shall be avoided as far as,

in the Engineer's Representative opinion, possible and practicable. Where it is intended that the spacing blocks or construction ties shall be removed whether before or after the concrete has set, the making good of the concrete shall be subject to the Engineer's Representative's approval. The removal of the blocks or ties must not jeopardise the stability of the construction. If, with the approval of the Engineer's Representative, the spacing blocks and construction ties are allowed to remain in the concrete then they shall be of such material and of such quality that they do not prejudice the strength of the work. Concrete spacing blocks shall be made of concrete at least equal in quality to the main concrete. Metal ties shall be positioned such that they do not come into contact with any of the reinforcement or fittings and no part of the tie shall be permanently embedded in the concrete nearer than 5 cm to the exterior surface of the concrete.

All holes shall be filled with 1:2 cement mortar.

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3.13.3 Slab Forms

Where timber is used for the soffits of slabs, the boards shall be placed and laid perfectly true with close joints to prevent the percolation of liquid or fines from the concrete. Tongue and groove planks shall be used if specified. All requisite bearer and struts shall be adjusted in position and placed where necessary on bearers as specified in the case of beam forms.

3.13.4 Type of Formwork

3.13.4.1 Exposed Concrete Faces for Bridges

All concrete faces shall be left as struck with a fair face, true to line finish.

In order to have the finish as it will be formed, approved by the Engineer, test pieces of 1 sq.m vertical panel 25 cm thick shall be cast. After approval they shall be retained in position until the concrete works have been completed then they shall be demolished and removed from the Works. After careful inspection, all superfluous fines and similar projections shall be carefully removed. No render or other applied finish shall be used to obtain a fair face to the concrete. All concrete faces to be exposed in the finished works shall be adequately protected against damage and surface staining during the execution of the Works.

3.13.4.2 Sawn Formwork

Shall be used for all culverts.

3.13.5 Preparation of Formwork for Concreting

Immediately before the concrete is deposited, the formwork shall be thoroughly cleaned out and freed from sawdust, shavings, wire cuttings, dust, sand, clay and all other deleterious and extraneous materials.

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Temporary openings shall be provided in the formwork to facilitate this work. The inside surfaces of the formwork shall, immediately prior to final erection, be coated with mould oil. The mould oil shall be of approved type and shall be applied uniformly and the quantities used shall be the minimum consistent with its purposes. The Contractor shall ensure that all steel reinforcement and adjoining concrete surfaces are kept free of mould oil. All formwork and reinforcement shall be clean and free from standing water immediately before placing concrete.

3.13.6 Approval of Formwork Before Concreting

The Contractor shall in all cases request the approval of the formwork by the Engineer's Representative in sufficient time to allow an inspection to be made and shall not commence concreting until such approval is obtained. The period between the Contractor's request for approval and his intention to commence concreting shall be not less than one clear normal working day and the Engineer's Representative may require a longer period if, in his opinion, the formwork is of such complexity as to require it.

Such approval shall not absolve the Contractor of his responsibilities under the Contract.

3.13.7 Removal of Formwork

All formworks shall be struck without jarring the concrete or subjecting the same to sudden shock.

Before striking any formwork, the Contractor shall satisfy himself that

the concrete is sufficiently hardened to bear its own load and any other loads that may be placed on it.

No formwork is to be removed, if in the opinion of the Engineer's

Representative, the concrete has not set sufficiently. approval of the Engineer's Representative shall not absolve the Contractor of his responsibilities under the Contract.

Subject to the above and the concrete test cube results, the minimum periods for the removal of formwork generally are as follows:

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Sides of beams, walls and columns - 2 days Soffits of beams and slabs (props left in) - 7 days Removal of props (beams and slabs) - 14 days Soffits of precast beams - 7 days

(These times may be reduced only with the written approval of the

Engineer)

In the case of the special types of formwork, striking times are to be approved by the Engineer.

If a beam slab is required to support a construction load in excess of its design load, the beam or slab is to be propped until the supported construction has reached the age when the propping may be removed. No supports for the shuttering may be left in the finished concrete without the written permission of the Engineer.

3.13.8 Concrete Below Ground

All concrete placed below ground level shall have a minimum

protection to its outside faces with a bituminous membrane as per Clause 9.2.1.2 of this Specification.

3.14 READY MIXED CONCRETE

3.14.1 Compliance with Specification The use of concrete delivered to the Site in a plastic condition and ready

for placing in its final position shall be permitted subject to the following conditions:-

(a) The constituent materials and the concrete mix shall comply with

the requirements of this Specification.

(b) The concrete shall be produced in accordance with the standards laid down in the current edition of the "Authorisation Scheme for Ready Mixed Concrete", published by the British Ready Mixed Concrete Association (B.R.M.C.A.), except that

(i) Para. 11.1 (i) of the above publication shall be replaced by

item (d) below.

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(ii) Water shall be added to the mix under the control of the

central batching plant.

(iii) Dry batching with water added on site will not be permitted.

(c) The concrete shall be supplied by a depot approved by the Engineer and Dubai Municipality.

d) The concrete shall be placed in its final position and left

undisturbed within 1-1/2 hours maximum of the time when the cement first comes into contact with wetted aggregates, ie. the time when hydration of the cement commences. If the temperature is less than 4°C or if the temperature is above 21°C, this period shall be reduced to one hour.

e) The drum of the agitator truck shall be placed in its final position

and left undisturbed within 1.5 hours maximum of the time when the cement first comes in contact with wetted aggregates, ie. The time when hydration of the cement commences. If the temperature is less than 4 °C or if the temperature is above 21 °C, this period should be reduced to one hour.

f) the truck mixer should discharge concrete at approximately 0.5

m3 per minute. If this rate is not possible, it is advantageous for the concrete to be discharged as quickly as possible especially during high ambient temperature conditions. The concrete shall be delivered and completely discharged within 1.5 hours or before the drum has revolved 300 times after the introduction of water to the cement and aggregates.

g) In order to ensure the uniformity of mixing the following test,

from ASTM Standard C94, shall be carried out: (i) Samples of concrete shall be taken from about 1/6 and 5/6

points of a batch, and the differences in the properties of the two samples should not exceed any of the following:

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Density of concrete calculated to an air-free basis – 16 kg/m3 Air content, volume % of concrete – 1%

Slump = 25mm when the average is 100 mm, sand 40 mm when the average is 100 mm to 150 mm

Percentage retained on 5 mm sieve – 6% Density of air-free mortar – 1.6% Compressive strength, average 7-day strength – 7.5%

h) All the material for the concrete shall pass the specification

requirements and concrete shall be verified with DM-DCL

3.14.2 Pumping Concrete

Pumped concrete is defined as concrete that is conveyed under pressure either through rigid or flexible hose, and discharged directly into the desired area. Pumping may be used for almost all concrete construction but is especially useful where there is inadequate space for other concrete placing equipment to be operated.

A steady supply of pumpable concrete is necessary for satisfactory pumping. Pumpable concrete, like conventional mixes, requires good quality control; ie, properly graded uniform aggregates, and materials uniformity and consistently batched and thoroughly mixed.

3.14.3 Field Control

Quality concrete in the field is the ultimate objective to be attained; a high level of quality control must be maintained. The locations at which samples for testing the concrete are taken is extremely important. Sampling according to ASTM C94, is for the acceptability of the ready-mixed concrete. However, the quality of the concrete being placed in the structure can only be measured at the placement end of the pipeline. Where appropriate, sampling at both the truck discharge and point of final placement should be employed to determine if any changes in the slump, air content, and other significant mixture characteristics occur. When sampling at the end of the placement line, great care should be taken to ensure that the sample is representative of the concrete going into the placement. Changing the rate of placing and/or the boom configuration can result in erroneous test results.

3.14.4 Remixing

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Fresh concrete that is left to agitate in the truck mixer tends to stiffen before initial set develops. This concrete shall not be used if the following conditions apply; (1) the maximum water to cement ratio will be exceeded, (2) the maximum slump will be exceeded, and (3) the maximum number of revolutions or mixing time to placement time will be exceeded.

3.14.5 Documentation

The Engineer shall receive copies of the delivery tickets for each batch of concrete, and have access to a site record book maintained by the Contractor in which the following information is recorded for each batch of concrete delivered:-

(i) Delivery ticket number.

(ii) Slump of the concrete, testing on site immediately prior to placing.

(iii) Time when concrete is placed in position and left undisturbed. (iv) Location that the concrete is placed. (v) Works test cube reference.

3.15 REINFORCEMENT STEEL

3.15.1 General

This work shall consist of furnishing, fabricating and placing steel

reinforcement bars of the grade, type, quality, size, shape and quantity

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designated, all in accordance with these Specifications and the details shown on the Drawings.

The Contractor shall be responsible for furnishing reinforcing steel in

sufficient quantity and of the proper sizes, lengths and shapes shown on the Drawings for any given structure.

3.15.2 Material Specifications

All reinforcement bars shall be of a deformed type in accordance with

BS 4449, except that plain bars may be used where specifically indicated on the Drawings. Plain bars shall be in accordance with BS 4449.

All steel reinforcement shall conform to the requirements of the

Specifications for Deformed High Yield Steel Bars, Grade 460 Type 2, unless otherwise shown on the Drawings or specified by the Engineer.

Mild steel where specified or called for shall be either deformed or plain

bars complying with ASTM A615 structural grade or BS 4449 or any equivalent National Standard as directed and approved by the Engineer.

Tying wire shall be No.16 gauge soft annealed iron wire or No. 18

gauge stainless steel wire or the equivalent AASHTO specification for tying wire.

Welded wire fabric shall be used as reinforcement for concrete where

shown on the Drawings and as directed. Welded wire fabric shall conform to the requirements of AASHTO M55 or to BS 4483.

All reinforcement shall be protected against corrosion with a fusion-

bonded epoxy coating in accordance with the requirements of ASTM A775/A775M and BS 7295.

The Contractor shall be responsible for obtaining the Engineer’s

approval to the steel bars prior to coating commencing. Such approval will in no way relieve the Contractor of his responsibilities under the Contract.

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The frequency of sampling and method of quality control shall be in accordance with BS 4449 latest edition.

For steel reinforcement, please refer to clause 4/8 “Reinforcing Bars” of

Section 4 – Concrete Works of DM Roads Dept. General Specification. The Contractor shall furnish to the Engineer a certificate of compliance

for each shipment of coated steel bars. The certificate of compliance shall state that representative samples of the coated bars have been tested and that the test results comply with the requirements of the Specifications.

3.15.3 Construction of Reinforcement

Steel reinforcing shall be stored on timber packing clear of the ground.

The steel bars shall be free from sharp deformations, rolled-in silvers, deep recesses or surface faults/blemishes which could result in inefficient or inadequate coating. When fixed in the work and immediately prior to concreting, steel reinforcing shall be entirely free from loose mill scale, loose rust, oil, grease, paint, mould oil, and all other deleterious and extraneous material. All hooks, bends, etc., unless otherwise shown on the Drawings shall be to BS 4466.

Before ordering reinforcing steel, the Contractor shall prepare bar

bending schedules at his own cost and submit them to the Engineer for his approval. Bar schedules shall show the weight of each bar, the total weight of each bar size and the total weight of bars, and bending diagrams for bars in accordance with BS 4466. The length of each bar shall be calculated in accordance with BS 4466 except that the minimum internal bending radius shall be four times the bar diameter.

The Contractor shall also provide and submit to the Engineer for approval any working drawings additional to the Contract Drawings which may be found necessary for the production of bar bending schedules or for the completion of the Works.

The Engineer’s approval of the Contractor’s working drawings and bar

bending schedules shall in no way relieve the Contractor of responsibility for the correctness of such drawings or schedules.

Steel reinforcement shall be bent accurately to the shapes and

dimensions shown on the approved bar bending lists or drawings. Bars shall be bent round mandrels of the requisite diameter.

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Steel reinforcement shall be cut and bent in accordance with BS 4466.

Cutting or bending by the application of heat is not permitted. Welding of reinforcement shall only be permitted when approved in writing by the Engineer. If such approval is given then the workmanship shall be in accordance with BS 5135. The Contractor shall submit full technical details of his proposed procedures prior to seeking approval.

Hot rolled high yield bars shall not be straightened or bent again, having

once been bent. If the Engineer gives approval to bend mild steel reinforcement projecting from the concrete, the internal radius of bend shall not be less than four times the nominal size of the bar.

Links, hoops, stirrups are generally to be bent round pins of the same

diameter as the bars they are to embrace. Where however, such bars are less in diameter than twice the diameter of the link, the radius of the bend shall be equal to the diameter of the link.

3.15.3.1 Placing Reinforcement

The number, size, form and position of all reinforcement shall, unless

otherwise directed or authorized by the Engineer, be strictly in accordance with the Drawings. Nothing shall be allowed to interfere with the disposition of the reinforcing bars. Bars generally must be of the required lengths. Welding of the bars will not be permitted. Lapping of the bars other than the lap splices shown on the Drawings should be avoided. The Engineer may approve certain lappings under special conditions. All lappings should comply strictly with the AASHTO specifications, namely Article 1.5.6. Clause "c".

The steel reinforcement shall be firmly held in position by wire ties and

concrete blocks or other approved spacers designed to maintain the correct clear cover of concrete over steel reinforcement. They shall be as small as possible consistent with their purpose, and of a shape acceptable to the Engineer. Minimum cover to reinforcement shall be 50 mm unless otherwise detailed. The position of spacers and their method of use shall be approved by the Engineer. The steel reinforcement shall be so connected as to form a rigid cage.

All intersecting bars shall be bound together with No.16 gauge soft iron

wire with the ends of the wire turned into the main body of the concrete.

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3.15.3.2 Maintaining Reinforcement in Position Concrete distance blocks shall, unless otherwise directed, be used

between the reinforcement and the bottom and sides of the forms to ensure correct placing and cover of the bars. The strength of such concrete distance blocks shall be not less than that of the main concrete. The greatest care shall be taken to prevent any displacement or bending of the members of the reinforcement adjusted and temporarily fixed in position before commencement of the concreting. Reinforcement temporarily left projecting from the concrete at construction of other joints shall be adequately protected against displacement both during concreting and afterwards and shall not be bent out of position unless agreed by the Engineer's Representative. During the concreting competent steel fixer shall be in attendance to re-set any reinforcement inadvertently displaced.

3.15.3.3 Approval of Reinforcement Before Concreting

The Contractor shall in all cases request the approval of the Steelwork

by the Engineer's Representative in sufficient time to allow an inspection to be made and shall not commence concreting until such approval is obtained. The period between the Contractor's request for approval and his intention to commence concreting shall not be less than one clear normal working day and the Engineer's Representative may require a longer period if, in his opinion, the reinforcement is of such complexity as to require it.

Such approval shall not absolve the Contractor of his responsibilities

under the Contract. 3.16 PRECAST CONCRETE KERBS, EDGINGS & QUADRANTS

Precast concrete kerbs and edgings shall be hydraulically pressed and they and precast concrete quadrants shall comply with the requirements of BS 7263: Part 1 and to the dimensions and shapes shown on the Drawings and/or as directed by the Engineer. They shall be Class B concrete with sulphate resisting cement as indicated in Clause 3.2.7 of

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this Specification. They shall be uniform in colour free from cracks, flaws or other defects with well defined arises. The kerbstones shall be 900 mm long or as directed by the Engineer's Representative. Samples of kerbstones proposed to be used shall be submitted to the Engineer for his approval prior to order or manufacture. Kerbstones shall not be used before they have been inspected and approved by the Engineer. They shall be fully cured when delivered to site (28 days min.). Kerbstones shall be laid on concrete Class C bedded on 1:3 sand cement mortar as specified and/or as directed by the Engineer. All kerbstones shall be well bedded and settled in place true to line and level with a suitable wooden mould. Before kerbstones shall be approved it should be ensured that their top surfaces are in a uniform plane and their front faces are in correct alignment. Any kerbstones not satisfying these requirements or having cracked or broken arises or faces shall be removed and replaced or reset as instructed by the Engineer. Joints between kerbstones shall be not less than 3 mm nor greater than 5 mm in width and shall be uniform from top to bottom. Joints shall be left open. Where precast kerbs of straight section are laid to form radii, joints should be filled with non-shrinkage mortar, and expansion joints (using flexel or similar joint filler) shall be provided at 3 m centres. For radii of 10 m or less quadrants shall be used. Kerbs of a reduced size shall only be used for this condition where approved by the Engineer. Tolerance in top level of kerbstones and horizontal alignment shall be ± 3 mm. All kerbstones shall be painted alternately black and white. The paint shall be an approved concrete paint giving a nominal thickness of 100 microns in two applied coats. Tranverse strength and Water Absorption shall be in accordance with BS 7263 : Part 1.

3.17 IN-SITU CONCRETE EDGING

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In-Situ concrete edge strips shall be to the cross section shown on the drawings and the class of concrete made with sulphate resisting cement indicated thereon in accordance with Clause 3.2 of this Specification. The edge strip shall be formed in as long lengths as possible and the form work shall be set on the top surface of the sub-base, set to produce the line and level in accordance with the requirements of this Specification. Care must be taken to ensure that the top surface is carefully finished to achieve these requirements and to provide the control of the wearing course. Expansion joints will be provided with an approved joint filler at maximum 3 m centres as shown on the drawing and/or as directed by the Engineer. The kerb shall be protected against covering or splashing by bitumen or cement.

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3.1 GENERAL The prevailing standard for all concrete work shall be BS 8110 and such

amendments as shall be approved by the Engineer in accordance with the CIRIA Guide to Concrete Construction in the Gulf Region.

Concrete work shall consist of furnishing all materials and constructing structures of the forms, shapes and dimensions shown on the Drawings or as directed, using Portland Cement concrete, in accordance with the details shown on the Drawings and these Specifications. Portland Cement concrete shall consist of a mixture of Portland Cement, fine aggregate, coarse aggregate, water and additives when required. The mixture shall be proportioned, mixed, placed and cured in accordance with the requirements of BS 8110: Part 1. Where an additional clause conflicts or is inconsistent with the requirements of BS 8110 the additional clause shall always prevail. The concrete mixes shall be designed mixes for special or ordinary concrete as defined in BS 8110, the design requirements of which are laid down in this Specification.

3.2 MATERIALS

3.2.1 Cement

3.2.1.1 General

Only Sulphate Resisting Cement as specified in Clause 3.2.1.3 shall be used unless otherwise directed. Unless otherwise approved by the Engineer all cements shall comply with the following requirements:- - The acid soluble alkali level measured as Na2O + 0.658 K2O

shall not exceed 0.6% by weight determined by the test method described in BS EN196-21.

- The specific surface (fineness) shall not be greater than 325

m2/Kg and not less than 225 m2/Kg when tested as described in BS EN196-6.

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The cement shall be of approved manufacture and shall be delivered in bags with seals unbroken, or delivered in bulk in approved containers which shall bear the manufacturer’s name, cement type and the date of manufacture. Test certificates from the manufacturers or suppliers shall be submitted for each consignment and shall indicate the results of the tests for compressive strength, setting time, soundness and fineness carried out in accordance with the requirements of the relevant BS or ASTM standards. Further tests may be required by the Engineer after the cement is delivered and stored on the site. The failure of any sample to satisfy the BS or ASTM requirements shall entitle the Engineer to reject the entire consignment from which it was taken. Cement shall be stored immediately upon receipt at site in such a way to keep it away from water and moisture at all times. The Contractor shall provide a method statement for the storage of cement which shall be approved and implemented before any cement is delivered to site. Consignments shall be used in the order in which they were delivered. Any consignment not used within 2 months from the date of manufacture will not be allowed to be used in the Works. No cement from any consignment shall be used in Permanent Works without the approval of the Engineer. Cement which the Engineer considers to have deteriorated in any way shall not be used and shall be removed from site without delay. One brand only of cement as approved by the Engineer shall be used throughout the Works unless otherwise authorised by the Engineer in writing. Differing types of brands shall not be mixed together for use in the Works.

3.2.1.2 Ordinary Portland Cement

Ordinary portland cement (OPC) shall comply with BS 12 or ASTM C150 Type 1. The tricalcium aluminate content shall lie within the range of 4% to 13%. The heat of hydration shall not exceed 290 Kj/Kg at 7 days when tested in accordance with ASTM C186.

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3.2.1.3 Sulphate Resisting Cement

Sulphate resisting cement (SRC) shall comply with BS 4027 or ASTM C150 Type 5. The heat of hydration shall not exceed 290 Kj/Kg at 7 days when tested in accordance with ASTM C186. The strength class shall be ASTM Type V with average compressive strength (N/mm2) for mortar cubes of 15 and 20 at 7 and 28 days respectively.

3.2.1.4 Moderate Sulphate Resisting Cement Moderate sulphate resisting cement (MSRC) shall comply with ASTM

C150 Type 2 but containing not less than 4% and not more than 8% proportion by weight of tricalcium aluminate. In either case the cement shall not contain more than 2.7% proportion by weight of sulphur trioxide.

3.2.2 Fine Aggregate for Concrete and Mortar Fine aggregate for concrete shall consist of natural screened and washed

sand or crushed sand having hard and durable particles, or of other inert materials with similar characteristics. It shall not contain harmful material such as salts, clay lumps, tree roots, shale, iron pyrites, coal, mica, organic matter or any deleterious matter which may attack the reinforcement, in such a form or in sufficient quantity to affect adversely the strength and durability of the concrete. If necessary, the aggregate shall be washed and sieved to remove the deleterious substances. Beach sand shall not be permitted for use in concrete mixes.

The fine aggregate shall comply in all respects with the requirements of

BS 882 and shall also comply with Dubai Municipality Administrative Order No. 143/91. In addition to the above, fine aggregate for concrete shall meet the requirements in Table 3-1.

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Table 3-1. Limits for Properties of Fine Aggregates for Concrete Type Test Method Permissible Limits

1. Magnesium Sulphate

Soundness (5 Cycles) ASTM C88 Max. 12%

2. Clay Lumps and Friable Particles

ASTM C142 Max. 1% by weight

3. Organic Impurities

ASTM C40 Lighter than standard

4. Material Finer than 0.075 mm

ASTM C117 Max. 3%

5. Acid Soluble Chlorides (Cl)

BS 812: Part 117

For reinforced concrete made with: SRC OPC & MSRC For mass concrete made with: SRC OPC & MSRC For prestressed concrete and heat-cured reinforced concrete

Max. 0.03% Max. 0.03% Max. 0.03% Max. 0.03% Max. 0.03%

6. Acid Soluble Sulphates (SO3)

BS 812: Part 118 Max. 0.3% by weight of fine aggregate

7. Water Absorption

ASTM C128 Max. 2.3%

8. Specific Gravity (apparent)

ASTM C128 Min. 2.6

9. Sand Equivalent (when aggregate other than natural sand is approved)

ASTM D2419 Min. 75

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Fine aggregate of fine grading (BS 882) shall not be used. Fine aggregate shall conform to one of the gradings given in Table 3-2 (reproduced from BS 882).

Table 3-2. Grading of Fine Aggregate for Concrete BS 410 Percentage by Weight Passing BS Sieve

Test Sieve (mm)

Coarse Medium

10 100 100 5 100 100

2.36 60 - 100 65 - 100 1.18 30 - 90 45 - 100 0.60 15 - 54 25 - 80 0.30 5 - 40 5 - 48 0.15 0 - 15 0 - 15

3.2.3 Coarse Aggregate for Concrete

Coarse aggregate for concrete shall consist of natural gravel, crushed gravel, or crushed stone, free from coating of clay or other deleterious substances. It shall not contain harmful materials such as salts, iron pyrites, coal, mica, laminated materials, tree roots, shale, or any materials which may attack the reinforcement, in such a form or in sufficient quantity to affect adversely the strength and durability of the concrete. If necessary, coarse aggregate shall be washed to remove deleterious substances.

The coarse aggregate shall comply in all respect with the requirements of BS 882. The coarse aggregate shall also fulfill the requirements in Table 3-3.

Table 3-3. Limits for Properties of Coarse Aggregate for Concrete

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Type

Test Method Permissible Limits

1. Flakiness Index BS 812: Part 105 Max. 25 2. Elongation Index BS 812: Part 105 Max. 25 3. Ten Percent Fines Value or

Impact Value BS 812: Part 111 BS 812: Part 112

Min. 100KN Max. 30%

4. Los Angeles Abrasion ASTM C131/C535

Max. 30%

5. Shell content BS 812: Part 106 Max. 3% by weight

6. Magnesium Sulphate Soundness (5 Cycles)

ASTM C88

Max. 12%

7. Clay Lumps and Friable Particles

ASTM C142 Max. 1% by weight

8. Material Finer than 0.075 mm

ASTM C117 Max. 1%

9. Acid Soluble Chlorides (Cl) For reinforced concrete made with : SRC OPC & MSRC For mass concrete made with:

SRC OPC & MSRC For prestressed concrete and heat-cured reinforced concrete

BS 812: Part 117 Max. 0.01% Max. 0.02% Max. 0.02% Max. 0.04% Max. 0.01%

10. Acid Soluble Sulphates (SO3)

BS 812: Part 118 Max. 0.3% by weight of coarse

Aggregate 11. Water Absorption ASTM C127 Max. 2% 12. Specific Gravity (apparent) ASTM C127 Min. 2.6 13. Drying Shrinkage BS 812: Part 120 Max. 0.05%

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The coarse aggregate shall conform to the gradings given in Table 3-4 in accordance with the nominal size of aggregate specified (reproduced from BS 882). Table 3-4. Gradings of Single Size for Coarse Aggregate

Sieve Size

Percentage by Weight Passing BS Sieve for Nominal Sizes

(mm) 40 mm 20 mm 14 mm 10 mm 50 100 - - -

37.5 85 - 100 100 - - 20.0 0 - 25 85 - 100 100 - 14.0 - - 85 – 100 100 10.0 0 - 5 0 - 25 0 – 50 85 - 100 5.0 - 0 - 5 0 – 10 0 - 25 2.36 - - - 0 - 5

3.2.4 Combined Aggregate Approved coarse aggregate and fine aggregate in each batch of concrete

shall be combined in proportions as specified in BS 882 and as approved by the Engineer. However, in no case shall materials passing the 0.075 mm sieve exceed three (3) percent by weight of the combined aggregate. The combined concrete aggregate gradation used in the work shall be as specified, except when otherwise approved or directed by the Engineer. Changes from one gradation to another shall not be made during the progress of the work unless approved by the Engineer. Naturally occuring sand/gravel mixtures (all in aggregates) shall not be used unless otherwise directed by the Engineer.

3.2.5 Water 3.2.5.1 General

Water for washing aggregate and for mixing or curing of concrete shall

be fresh, clean and substantially free from oil, acids, alkali, sewage, deleterious mineral or organic matter. Water shall comply in all respects with BS 3148. It shall not contain impurities in sufficient amounts to cause discoloration of the concrete.

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All sources of water for use with cement shall be approved by the Engineer. Sources of water shall be maintained at such depth and the water shall be withdrawn in such a manner as to exclude silt, mud, grass and other foreign matter. If at any time during construction the water from an approved source becomes unsatisfactory, the Contractor will be required to provide satisfactory water from some other source.

3.2.5.2 Specific Requirements

Water for washing aggregate and for mixing or curing of concrete shall be tested in accordance with BS and ASTM standards and shall meet the following requirements:

Table 3-5. Chemical Limitations for Mixing Water Parameter Maximum

Concentration Limit

Test Method

1. Chlorides as C1 250 mg/l ASTM D512 2. Sulphates as SO3 350 mg/l ASTM D516 3. Alkali carbonates and bicarbonates

500 mg/l

ASTM D513

4. Total dissolved ions, including 1, 2 & 3 above

2,000 mg/l

BS 1377: Part 3

5. pH Min. 7/max. 9 ASTM D1293 The temperature of water for concrete should not be less than 5° C nor more than 25°C. Water may be cooled to not less than 5°C by the gradual addition of chilled water or ice but on mixing, no ice particles should be present in the mix. Alternatively, flaked ice may be used. The ice to be used should be crushed and should be the product of frozen water which complies with the above requirements.

3.2.6 Admixtures Unless agreed by the Engineer neither admixtures nor cements containing additives shall be used.

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Where the use of admixture had been agreed by the Engineer, they shall conform to the requirements of Type A, Type D, Type F or Type G as specified in ASTM C494 and shall be used in strict accordance with the manufacturer’s instructions. The Contractor shall be entirely responsible for the use of any approved admixtures. Samples of proposed admixtures shall, if required, be submitted to an approved testing authority by the Contractor in order to ascertain its suitability for use in the Works. Approved methods and equipment shall be used for dispensing and incorporating the admixture into the concrete. The dispensing unit shall be designed so that the discharge of the admixture is visible. The cost of such admixtures shall be included in the cost of concrete and no extra payment shall be made if they are used. The proportions of cement, fine aggregate and water shall be determined by the Contractor before concreting commences and submitted together with such test results as may be required to the Engineer for approval and the Contractor shall not commence concreting before such approval is given nor shall he alter or vary in any way the proportion of mix unless he submits fresh test results and mix proportions to the Engineer for approval. The approval by the Engineer of such mix designs does not in any way absolve the Contractor of any of the requirements of the Specifications.

3.2.7 Concrete Mix Specification

The classes of concrete and their respective minimum cement content, consistencies and the minimum required compressive strengths shall be as shown:

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Table 3-6. Concrete Classification and Mixes

Class of Concrete

Comp. Strength (N/mm2)

Slump (mm)

Min.Cement Content (kg/m3)

Max. Free Water/Ceme

nt Ratio

7 days 28 days

A (30/20/SRC)

20 30 25 - 75 310 0.55

B (25/20/SRC)

16 25 25 - 75 275 0.60

C (15/20/SRC)

10 15 25 - 100

250 0.65

The chloride and sulphate levels in the concrete mix shall comply with the requirements of Table 3-7.

Table 3-7. Maximum Limits of Chloride & Sulphate in Concrete Mix

Type of Concrete Chlorides as

C1* (According to BS 1881:Part

124)

Sulphate as SO3*

(According to BS 1881:Part

124) a. For reinforced concrete if made with OPC/MSRC if made with SRC

0.30% 0.06%

3.70% 3.70%

b. For mass concrete if made with OPC/MSRC if made with SRC

0.60% 0.12%

3.70% 3.70%

c. For prestressed concrete and heat-cured reinforced

concrete

0.10% 3.70%

*Maximum limits of chloride and sulphate content as a percentage by weight of cement in the mix.

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The OPC and MSRC cements can also contain chlorides, the relevant standard BS 12 allows up to 0.1% C1. Therefore any chloride content present in the cement has to be taken into account while computing total C1 in the mix. In case the cement contains the maximum limit of 0.1% Cl, then the aggregates, water and admixtures used for prestressed concrete or heat-cured reinforced concrete should be absolutely free of chlorides.

3.2.8 Cement Mortar and Grout

Unless otherwise specified, mortars and grouts shall be composed of Ordinary Portland Cement (satisfying Clause 3.2.1) and sand (satisfying Clause 3.2.2) in the following proportions:-

NOMINAL PROPORTIONS Quality Portland Cement Sand G 1 1 1 G 2 1 2 G 3 1 3

The amount of water (satisfying Clause 3.2.5) added shall just be sufficient to make the mortar or grout workable consistent with its purpose.

3.3 MIXING AND TESTING

3.3.1 Samples of Aggregates

Before any material from a particular source is used, the Contractor shall obtain representative samples of fine and coarse aggregates and carry out the necessary tests and analyses to show that the samples comply with the Specification. During the progress of the Works, the grading and chemical characteristics may be checked at frequent intervals. Sampling of aggregates shall be carried out in accordance with BS 812: Part 101 and Part 102.

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The results of these tests shall be submitted to the Engineer and his approval shall be obtained before any of the material is used in the Works. Part of each sample will be required for concrete trial mixes and part shall be retained for comparison with subsequent deliveries. No deliveries in bulk are to be commenced until such samples are approved by the Engineer as complying with this Specification.

3.3.2 Trial Mixes for Concrete

Following the Engineer's approval of the materials for each class of concrete, the Contractor shall prepare trial mix of each grade of concrete in the presence of the Engineer's Representative. Each trial mix shall comprise not less than 1/3 of a cubic metre of concrete and shall be mixed in an approved type of concrete mixer similar to that which the Contractor propose to employ on the Works. The quantities of all ingredients of trial mix including water shall be carefully determined by weight according to the approved mix design. Each trial mix shall show no tendency to segregate when handled and compacted by the methods by which the Contractor proposes to handle and compact the grade of concrete in the Works and it shall be capable of adequate compaction by such methods.

3.3.3 Water/Cement Ratio

The quantity of water to be added to the cement and aggregates during mixing shall be just sufficient to produce a workable mix to enable it to be well compacted and worked into corners of formwork and around reinforcement. All mixes shall be designed in respect of the proportioning of water so that the Slump Test as carried out according to BS 1881: Part 102 shall be in accordance with the requirements laid out in Clause 3.2.7. Measurement of water on the Site shall take into account the moisture present in the aggregates, and Slump Tests shall be taken frequently to ensure that variations in the moisture content of the aggregate are fully taken into account in determining the amount of water to be added.

3.3.4 Measurement of Ingredients

The aggregates for the concrete shall be measured by weight but measurement by volume may be allowed in special circumstances with the approval of the Engineer.

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When the aggregates are to be measured by weight the weight batching machines shall be of a type approved by the Engineer's Representative. They shall be kept clean and in good condition and adjustment. At intervals as the Engineer's Representative may require, the Contractor shall check the accuracy of each weight-batching machine. When the aggregates are to be measured by volume, the proportions of fine and coarse aggregates shall be measured in well constructed gauge boxes, of dimensions approved by the Engineer's Representative to guarantee that whole multiples of such gauge boxes will ensure the use of one more whole bags or containers of cement and the capacity of the concrete mixer shall be such as to ensure that no splitting of cement bags or containers is required. Gauge boxes shall be properly filled and struck off level, addition of fine aggregates to allow for bulking due to moisture content being made as required. An efficient water measuring device shall be fitted to each concrete mixer. Any cement container shall be such as to contain an accurately weighed amount of cement.

3.3.5 Mixing Concrete

The concrete shall be mixed in a power driven machine of the batch type, no hand mixing being allowed. The mixer shall be large enough to admit the use of 1cement bag or container or whole multiples of bags or containers at a time. The mixing shall continue until there is a thorough distribution of the materials and the mass is uniform in consistency and colour. The period of mixing, judged from the time that all the ingredients including water are in the mixing drum shall be as ordered by the Engineer's Representative but shall not be less than 2 minutes or 20 revolutions of the drum whichever is the longer. Should there be for any reason a stoppage of greater than 30 minutes, the drum or other containers of the mixer shall be thoroughly washed and cleaned before mixing is resumed. On completion of the mixing the concrete shall be discharged onto clean boards or into clean barrows. The method of discharge from the mixer shall be such as to cause no segregation whether partial or otherwise of the concrete materials.

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3.3.6 Re-Mixing Concrete

Concrete which has commenced to set shall not be remixed either with or without additional water and in no case shall such concrete be used in the Works.

3.3.7 Concrete Testing 3.3.7.1 General

The compression tests shall be performed on cubes 150 x 150 x 150 mm as described in BS1881: Part 116. Sampling, making test cubes and curing of cubes shall be in accordance with BS 1881: Parts 101, 108 and 111 respectively. The following methods of testing shall apply to standard concrete cubes.

3.3.7.2 Preliminary Testing After the materials have been approved and at least 10 days before any

concrete is poured, the Contractor shall make 3 Nos. preliminary sets of test cubes. Each set of test cubes shall comprise of three cubes made from a single sample of concrete taken from the point of final discharge of the wet concrete. Each cube shall be made under the Engineer's Representative supervision. Cubes shall be tested as follows: one set shall be tested 7 days after the date of manufacture and one set 28 days after the date of manufacture. The third set will only be tested if the Engineer's Representative wishes to check the results of the tests on either of the other two cubes and shall otherwise be preserved by the Contractor until the end of the Period of Maintenance. Preliminary test cubes shall be made and tested for all grades of concrete and for all proposed variations of quality, quantity or origin of the aggregates and cement.

Should any of the test cubes crushed at 7 days or that crushed at 28 days

fall below the specified requirements and the failure is confirmed by the testing of the third set, the Contractor shall, on the Engineer's Representative's instructions alter the mix design and/or the source of aggregates, cement or water and/or the method of mixing including alteration of the type of mixer. The compressive strength of the concrete cube at 7 days shall be equal to or more than two thirds the required compressive strength at 28 days.

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3.3.7.3 Works Testing During the course of the construction of the Works, the Contractor shall

make test cubes as required by the Engineer's Representative. One set of six cubes will normally be taken from each individual concrete member, e.g. culvert invert, Irish crossings, but additional cubes shall be taken as directed by the Engineer's Representative. Three cubes will be tested at 7 days and three cubes at 28 days as the Engineer's Representative directs. Where the strength of the concrete is shown to be below that specified, the Contractor shall remove and replace at his own expense all concrete from the concerned pour. The Engineer may require the Contractor to cut out defective concrete from the Works at his own expense even though test cubes made from that concrete have not failed.

Durability tests of hardened concrete shall be carried out in addition to

Splitting Tensile Test, Water Absorption Test, ISAT and Depth of Water Penetration test.

3.3.7.4 Workability Testing The Contractor shall carry out slump test in accordance with BS 1881:

Part 102 and/or compacting factor test in accordance with BS 1881: Part 103 at such frequency as the Engineer's Representative considers necessary to ensure that the workability and consistency of the concrete is maintained in accordance with the specified mix or accepted mix design and the trial mix. But in any case workability tests shall be carried out at least once every two hours during which concrete is being mixed.

3.3.8 Frequency of Testing Aggregate and Concrete During the mixing and casting of concrete the frequency of testing for

control purposes shall be as indicated in Table 3-8 or as directed by the Engineer's Representative. No direct payment is made for testing. The price of this work is to be included in the bid prices of concrete.

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Table 3-8. Required Frequency of Testing Aggregates & Concrete Type of Test Frequency

Grading of Fine and Coarse Aggregate; Flakiness and Elongation Index; Aggregate Crushing Value

Once for each source prior to approval and once prior to casting of each lift for any major concrete structure or as directed by the Engineer

Concrete Cube

One set (Min. 6 Cubes) from each mixer for class of concrete and at 10m3. The point of sampling of fresh concrete shall be at delivery into the construction unless otherwise directed by the Engineer. Each set of cubes shall be made from a separate batch.

Compacting Factor Test As directed by the Engineer. Transverse Strength (as per BS 7263 : Part 1)

As directed by the Engineer.

Absorption Requirement(1) (as per BS 1881: Part 122)

As directed by the Engineer.

Slump Test

Once every hour from each mixer or as directed by the Engineer.

Mix Design

Once for each source of aggregate or every combination of sources or as directed by the Engineer.

Portland Cement One 2 Kg sample for quality test shall be taken from each 1,700 bags or equivalent weight. Sampling of cement shall be as per BS EN-7

Water A one gallon sample shall be obtained prior to use from, each source and at least every week for quality testing.

Note: (1) Maximum 2% after 30 minutes

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3.4 TRANSPORTING AND PLACING CONCRETE 3.4.1 General Requirements Concrete shall be taken from the place of mixing to the place of

depositing by approved methods which will prevent the segregation or loss of the ingredients and which are sufficiently rapid to ensure that the concrete does not commence to set before it is compacted in position. The concrete shall be deposited as near as possible to its final position in the Works and shall not be allowed to flow into position. Deposition of the concrete through chutes shall not be permitted and neither shall the concrete be dropped freely from a height exceeding 2.0 m. Pumping concrete through delivery pipes may be permitted but only with the prior approval of the Engineer's Representative.

No concrete shall be placed in a foundation until the extent of excavation and the character of bearing material have been approved and no concrete shall be placed in any structure until the placement of reinforcing steel and the adequacy of the forms and falsework have been approved. The concrete shall be placed in its final positions as soon as possible after it has been mixed, and in any case before the initial set has taken place. The Contractor shall ensure that concrete which has already been placed in position and commenced to set is not disturbed by the placing or compaction of further concrete nearby. All concrete shall be carefully worked around and between reinforcement and all other embedded fittings without such reinforcement or fittings being disturbed. Concrete is to be worked well up against whatever surface it joints. No concrete shall be mixed or placed when the light is insufficient, unless an adequate and approved artificial lighting system is operated and such night work is approved by the Engineer.

3.4.2 Placing Concrete in Hot Weather

Concrete shall only be placed where the general requirements iin regard to ambient and mix temperatures laid down in the CIRIA Guide to Concrete Construction in the Gulf Region are met. The parameters laid down therein shall only be exceeded with the prior written consent of the Engineer.

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Concrete shall not be placed when the shade air temperature exceeds 40° C or during periods of windblown dust or rain. The temperature of batched concrete at time of placing shall not exceed 32°C unless otherwise specified. Measures shall be taken to provide cool concrete and cool concreting conditions in order to reduce workability loss, premature drying of concrete and the development of high temperatures and temperature gradients in placed concrete. Proposed measures must be described in method statements and may include:- (a) Painting white or silver all storage vessels, hoppers, pipes, walls or

roofs which contain or convey aggregates, cement or mixing water. (b) Dampening the forms. (c) Reducing the concrete temperature to the lowest practical level by

procedures such as :- - Shading the aggregate. - Cooling the mixing water before use.

- Screening the mixing plant and transporting vehicles from wind, rain and sun.

(d) Erecting wind breaks and sunshades at the concrete placing

location. (e) Reducing the time between the placing of the concrete and the start

of curing to the minimum possible. (f) Minimizing evaporation (particularly during the first few hours

subsequent to placing the concrete) by suitable means such as applying moisture by fog spraying.

These measures are in addition to those specified for the curing of concrete. In contracts which small structures spread over a large site, such as sewerage contracts, where transportation times could be large, dry mixing of concrete with addition of water immediately prior to placing may be proposed. Method statements for such a proposal must describe methods for accurate batching of water.

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3.4.3 Placing Concrete in Water (Tremie Concrete)

Tremie concrete shall be deposited in water only if specified on the Drawings and/or directed by the Engineer and under the Engineer's supervision. Concrete to be deposited in water shall have the cement content increased by 25% at the Contractor's expense. Concrete shall be carefully placed in a compact mass in the space in which it is to remain by means of a tremie bottom dump bucket or other approved method that does not permit the concrete to fall through the water without adequate protection. The concrete shall not be disturbed after being deposited. No concrete shall be placed in flowing water and forms which are not reasonably watertight shall not be used for holding concrete deposited under water.

3.4.4 Blinding Concrete

Prior to placing any concrete on natural surfaces a blinding layer of Class C concrete shall be laid to a minimum of 75 mm thickness. This blinding shall be suitably curved prior to subsequent concrete placement. The blinding shall be clean and free from any dust or im-purities prior to subsequent concrete placement.

3.5 COMPACTING CONCRETE

3.5.1 Tamping

All concrete shall be thoroughly compacted to the maximum with approved rammers without any segregation in its final position before it commences to set. Care shall be taken to ensure that the use of spade type rammers does not cause segregation of the aggregates and water. Initial compaction of slabs shall be with approved rammers and compaction by a screed board shall be limited to that required for the final shape and finish. During the placing and compaction of reinforced concrete, a competent steel mixer shall be in attendance to adjust and correct if necessary the position of the reinforcement.

3.5.2 Vibrating

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Concrete shall be compacted by vibrating with an approved vibrator. The vibrators shall not be attached to any reinforcement or embedded fitting and where vibrators of the immersion type are used, care shall be taken to ensure that they do not come into contact with the reinforcement or embedded fittings. Freshly placed concrete shall not be vibrated in a manner likely to cause damage to concrete in other parts of the Works which has already taken its initial set. Concrete shall not be vibrated in such a manner and to such an extent as to cause segregation of the constituent materials. If shutter type vibrators are used they shall be augumented by immersion type vibrators if the thickness of the concrete member is more than 15 centimetres.

3.6 CURING OF CONCRETE

All concrete shall be protected from the harmful effects of sunshine, drying winds, rain, flowing water, or other adverse effect. For at least 7 days after placing, the concrete shall be prevented from drying out by being sprayed with fresh clean water and covered with hessian, clean sand or other approved material which shall be kept wet.

Whenever approved by the Engineer, membrane curing of concrete with an approved liquid may be used as an alternative to curing with water except that membrane curing liquid shall not be applied to surfaces of concrete from which the shuttering has been struck, until the concrete has been inspected and approved by the Engineer's Representative.

The concrete curing compound shall comply with the following requirements:

1) Only products which have been proved to be effective through

extensive use shall be proposed and manufacturers’ literature shall include recent test certificates illustrating effective quality control and high curing efficiencies.

2) All materials shall be supplied in the containers marked by the

manufacturer with his name, date of manufacture, shelf life, pot life and instructions for handling and application.

3) The liquid shall contain a white or silver colour pigment in

sufficient quantity to give a uniform colour when applied to the concrete surface.

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4) The liquid shall be of such chemical composition and consistency that it can be applied by an approved mechanical sprayer in fine spray to produce an even, uniform, impervious, continuous film within one hour of application which will not crack, peel or disintegrate within three weeks of application.

The compound shall not be poisonous, odorous or explosive and

shall not react chemically with cement. 5) Curing compounds shall not be applied to surfaces to which further

concrete or a surface finish is subsequently to be bonded unless the approval of the Engineer is obtained to the use of a water soluble type.

The Contractor shall ensure that all concrete is adequately protected

against inclement weather until properly set and shall if necessary provide additional protection to that specified above.

3.7 JOINTS IN CONCRETE

3.7.1 Intervals During Concreting The timetable for the depositing of concrete between construction joints

should be so arranged that no face of concrete shall be left for more than 20 minutes before fresh concrete is deposited against it. Pauses for meals, servicing of machines, changes of shift, etc., and the distribution of concrete among the positions where work may be proceeding simultaneously must be carefully organized to ensure that the above mentioned interval shall not be exceeded.

3.7.2 Construction Joints

Construction joints shall be as shown on the Drawings or as directed by

the Engineer's Representative. If the Contractor wishes to make additional construction joints he shall obtain the prior approval of the Engineer's Representative. Such approval may include the provision and placing of additional reinforcement at the Contractor's expense.

Construction joints shall be formed by inserting temporary vertical stopping-off boards to form tongue and groove joint with the concrete placed subsequently except if separately detailed on the Drawings. Unless otherwise shown on the Drawings construction joints shall be

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located as near as possible to the position of minimum shear and tensile stress in the concrete.

3.7.3 Jointing Fresh to Set Concrete

At a construction joint, the face of the previously placed concrete shall

be cleaned of any skin or laitance or loose material by brushing with a wire brush or other approved method and washing with clean water. Insecurely held aggregate shall be removed. Excess water shall be removed and the surface while still wet shall be covered with 1:2 cement mortar which must be vigorously stippled into the surface by means of a suitable stiff brush, the depositing of the fresh concrete following closely.

3.7.4 Expansion Joints

Expansion joints shall be constructed at positions shown on the

Drawings or as directed by the Engineer and shall be formed according to the instruction and dimensions shown on the Drawings.

Filled expansion joints shall be provided at every 6 m or as shown in

the drawings and/or directed by the Engineer for the kerb and concrete backing. Any excavated surface for the concrete bedding should be watered and compacted to a minimum 95% of optimum density.

3.7.5 Expansion Joint Filler Expansion joint filler shall be composed of approved durable

non-extruding fibrous material suitably impregnated to prevent deterioration. Sheet bitumen fillers will not be accepted. Preformed strips of expansion joint filler shall be of such a nature as not to be permanently deformed or broken by twisting, bending or other normal handling on site. Samples shall be submitted for approval before ordering. The vertical expansion joints in kerbs and parapets shall be formed with approved vertical seal. Such vertical seal shall adhere to the vertical face sealed and shall not flow under maximum local sun temperature nor shall it be sticky to the touch.

1) Expansion joints for precast upstand kerbs shall be at 6 m. 2) For flush kerbs cast in-situ, at 2 m max. 3) For precast slabs, every 4 m min.

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3.7.6 Expansion Joint Sealing Compound

The sealing compound shall be of an approved polysulphide compound,

non-pouring grade for vertical application and pouring grade for horizontal application, as specified in Clause 9.2.1.2 (1) or it may be a rubber-bitumen compound.

The rubber-bitumen compound shall be a flexible weather resistant seal,

slump resistant unaffected by permanent immersion in water, or by alkalis or sulphates. The material shall have a minimum storage life of 12 months in original containers stored in cool dry conditions and a density of 1.30 kg/litre.

The sealing compound shall adhere firmly to the concrete in all weather

conditions. The sealing compound shall not flow either along or down the joint during hot weather. The sealing compound shall be durable and shall not weather beyond the forming of a thin surface skin.

Samples shall be submitted for approval before ordering. Vertical sealer

shall be used with an approved priming compound. Application of the sealing compound shall be strictly in accordance with the Manufacturer's instructions.

3.7.7 Waterstop Across Joints in Concrete Structures Seepage of water through any joints in a water retaining or water

excluding concrete structure shall be prevented by the use of PVC Waterstop or other material as directed and approved by the Engineer. They shall be placed centrally as a water barrier across the designated joint in in-situ concrete structures and cast centrally into the edges of adjacent concrete components.

Waterstop shall be used at all Expansion and Contraction Joints in

concrete structures below water table. For a Construction Joint, requirement of a waterstop shall be indicated in the drawing. The Engineer may also require the Contractor to provide waterstop at any additional Construction Joint approved at his request.

Waterstop shall be extruded from high grade grey PVC Compound. Flat Dumbell plain web waterstop shall be used for a Construction Joint while for an Expansion Joint or a Contraction Joint, a centre bulb waterstop shall be used. The width of the waterstop shall depend upon

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the concrete thickness, the aggregate size and the position of reinforcement. In general, the following shall be taken as a guide to select the width, w, of a waterstop:-

w < t, but w > (6a+j) where, t = concrete thickness a = largest aggregate size j = width of Expansion Joint The following Technical Data shall apply :

Hardness : 42 - 52 BS Softness degrees at 25° C. Tensile strength : 13.8 N/mm2 minimum at 25° C. Elongation at break : 285 % minimum at 25° C.

3.8 INSPECTION OF CONCRETE

The Contractor shall not proceed with the surface finish or making good

of concrete surfaces until he has received the Engineer's Representative's permission to do so and he shall not apply cement slurry or mortar or any other coating to the concrete surfaces from which the shuttering has been struck until the concrete has been inspected and approved by the Engineer's Representative.

3.9 FAULTY CONCRETE WORK

The Contractor shall on the written instruction of the Engineer's

Representative remove and reconstruct any such portion of the work which in the opinion of the Engineer's Representative is unsatisfactory as regards quality of concrete, incorrect dimension of the cast portion, badly placed or insufficient reinforcement, honeycombing or other such cause as shall render the construction not up to the standard required and which in the opinion of the Engineer may affect the strength or durability of the construction.

3.10 REPAIRS TO CONCRETE

The method of repairing and replacing defective concrete which the Contractor proposes to adopt shall be submitted to the Engineer's

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Representative for prior approval and the repair shall be carried out in such manner as the Engineer may direct or approve.

3.11 SUPERVISION OF CONCRETE WORK

Throughout the progress of the concrete work the Contractor shall

employ and provide such supervision as is necessary to ensure

(a) the day to day control of the quality of the concrete and

(b) the mixing, transporting, placing, compacting, curing and protection of the concrete, and

(c) the carrying out of all testing as specified herein and any further

testing which the Engineer's Representative may require, and

(d) the conducting of investigations as the Engineer's Representative may require, and

(e) the preparation of reports and the keeping of such records as the

Engineer's Representative may require.

3.12 FINISHING OF CONCRETE

All concrete surfaces (except top faces of culvert decks) not requiring shuttering shall be trowelled to a smooth dense surface with the minimum of cement and fine particles being brought to the surface and shall be free from irregularities. Top faces of culvert decks shall be carefully screeded and tamped to the required shape and to a dense surface with the minimum amount of cement and fine particles being brought to the surface and should be free from irregularities greater than 3 mm in height or depth. Shuttered surfaces of concrete which will always be in contact with the ground may be cast against sawn timber. All other exposed shuttered surfaces including precast concrete shall be cast against steel, plywood or planed timber formwork and shall be carefully rubbed down with carborundum to remove all imperfections and irregularities. Surfaces which are honeycombed, porous or irregular and which in the opinion of the Engineer's Representative do not comply with the Specification shall be cut out and replaced with sound concrete as directed by the Engineer's Representative. The cost of all normal surface finishes and

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making good shall be deemed to be included in the tendered rate for the concrete.

3.13 DESIGN AND CONSTRUCTION OF FORMWORK

3.13.1 General

Formwork shall in every respect be adapted to the structure and the

required surface finish of the concrete. It shall include all temporary moulds for forming the concrete to the required shape and finish and for the support of such moulds. It shall be fixed in perfect alignment and securely ledged and braced so as to be able to withstand, without displacement deflection or movement of any kind, the weight of the construction and the movement of persons materials and plant. Joints shall be close enough to prevent the leakage of liquid and fine materials from the concrete.

The Engineer's Representative may at any time require the prior submission for approval of the Contractor's proposals for design and construction of formwork including supports. The formwork shall be constructed so as to permit its removal without damage to the concrete.

3.13.2 Spacing Blocks and Temporary Construction Ties

Internal spacing blocks and construction ties shall be avoided as far as,

in the Engineer's Representative opinion, possible and practicable. Where it is intended that the spacing blocks or construction ties shall be removed whether before or after the concrete has set, the making good of the concrete shall be subject to the Engineer's Representative's approval. The removal of the blocks or ties must not jeopardise the stability of the construction. If, with the approval of the Engineer's Representative, the spacing blocks and construction ties are allowed to remain in the concrete then they shall be of such material and of such quality that they do not prejudice the strength of the work. Concrete spacing blocks shall be made of concrete at least equal in quality to the main concrete. Metal ties shall be positioned such that they do not come into contact with any of the reinforcement or fittings and no part of the tie shall be permanently embedded in the concrete nearer than 5 cm to the exterior surface of the concrete.

All holes shall be filled with 1:2 cement mortar.

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3.13.3 Slab Forms

Where timber is used for the soffits of slabs, the boards shall be placed and laid perfectly true with close joints to prevent the percolation of liquid or fines from the concrete. Tongue and groove planks shall be used if specified. All requisite bearer and struts shall be adjusted in position and placed where necessary on bearers as specified in the case of beam forms.

3.13.4 Type of Formwork

3.13.4.1 Exposed Concrete Faces for Bridges

All concrete faces shall be left as struck with a fair face, true to line finish.

In order to have the finish as it will be formed, approved by the Engineer, test pieces of 1 sq.m vertical panel 25 cm thick shall be cast. After approval they shall be retained in position until the concrete works have been completed then they shall be demolished and removed from the Works. After careful inspection, all superfluous fines and similar projections shall be carefully removed. No render or other applied finish shall be used to obtain a fair face to the concrete. All concrete faces to be exposed in the finished works shall be adequately protected against damage and surface staining during the execution of the Works.

3.13.4.2 Sawn Formwork

Shall be used for all culverts.

3.13.5 Preparation of Formwork for Concreting

Immediately before the concrete is deposited, the formwork shall be thoroughly cleaned out and freed from sawdust, shavings, wire cuttings, dust, sand, clay and all other deleterious and extraneous materials.

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Temporary openings shall be provided in the formwork to facilitate this work. The inside surfaces of the formwork shall, immediately prior to final erection, be coated with mould oil. The mould oil shall be of approved type and shall be applied uniformly and the quantities used shall be the minimum consistent with its purposes. The Contractor shall ensure that all steel reinforcement and adjoining concrete surfaces are kept free of mould oil. All formwork and reinforcement shall be clean and free from standing water immediately before placing concrete.

3.13.6 Approval of Formwork Before Concreting

The Contractor shall in all cases request the approval of the formwork by the Engineer's Representative in sufficient time to allow an inspection to be made and shall not commence concreting until such approval is obtained. The period between the Contractor's request for approval and his intention to commence concreting shall be not less than one clear normal working day and the Engineer's Representative may require a longer period if, in his opinion, the formwork is of such complexity as to require it.

Such approval shall not absolve the Contractor of his responsibilities under the Contract.

3.13.7 Removal of Formwork

All formworks shall be struck without jarring the concrete or subjecting the same to sudden shock.

Before striking any formwork, the Contractor shall satisfy himself that

the concrete is sufficiently hardened to bear its own load and any other loads that may be placed on it.

No formwork is to be removed, if in the opinion of the Engineer's

Representative, the concrete has not set sufficiently. approval of the Engineer's Representative shall not absolve the Contractor of his responsibilities under the Contract.

Subject to the above and the concrete test cube results, the minimum periods for the removal of formwork generally are as follows:

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Sides of beams, walls and columns - 2 days Soffits of beams and slabs (props left in) - 7 days Removal of props (beams and slabs) - 14 days Soffits of precast beams - 7 days

(These times may be reduced only with the written approval of the

Engineer)

In the case of the special types of formwork, striking times are to be approved by the Engineer.

If a beam slab is required to support a construction load in excess of its design load, the beam or slab is to be propped until the supported construction has reached the age when the propping may be removed. No supports for the shuttering may be left in the finished concrete without the written permission of the Engineer.

3.13.8 Concrete Below Ground

All concrete placed below ground level shall have a minimum

protection to its outside faces with a bituminous membrane as per Clause 9.2.1.2 of this Specification.

3.14 READY MIXED CONCRETE

3.14.1 Compliance with Specification The use of concrete delivered to the Site in a plastic condition and ready

for placing in its final position shall be permitted subject to the following conditions:-

(a) The constituent materials and the concrete mix shall comply with

the requirements of this Specification.

(b) The concrete shall be produced in accordance with the standards laid down in the current edition of the "Authorisation Scheme for Ready Mixed Concrete", published by the British Ready Mixed Concrete Association (B.R.M.C.A.), except that

(i) Para. 11.1 (i) of the above publication shall be replaced by

item (d) below.

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(ii) Water shall be added to the mix under the control of the

central batching plant.

(iii) Dry batching with water added on site will not be permitted.

(c) The concrete shall be supplied by a depot approved by the Engineer and Dubai Municipality.

d) The concrete shall be placed in its final position and left

undisturbed within 1-1/2 hours maximum of the time when the cement first comes into contact with wetted aggregates, ie. the time when hydration of the cement commences. If the temperature is less than 4°C or if the temperature is above 21°C, this period shall be reduced to one hour.

e) The drum of the agitator truck shall be placed in its final position

and left undisturbed within 1.5 hours maximum of the time when the cement first comes in contact with wetted aggregates, ie. The time when hydration of the cement commences. If the temperature is less than 4 °C or if the temperature is above 21 °C, this period should be reduced to one hour.

f) the truck mixer should discharge concrete at approximately 0.5

m3 per minute. If this rate is not possible, it is advantageous for the concrete to be discharged as quickly as possible especially during high ambient temperature conditions. The concrete shall be delivered and completely discharged within 1.5 hours or before the drum has revolved 300 times after the introduction of water to the cement and aggregates.

g) In order to ensure the uniformity of mixing the following test,

from ASTM Standard C94, shall be carried out: (i) Samples of concrete shall be taken from about 1/6 and 5/6

points of a batch, and the differences in the properties of the two samples should not exceed any of the following:

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Density of concrete calculated to an air-free basis – 16 kg/m3 Air content, volume % of concrete – 1%

Slump = 25mm when the average is 100 mm, sand 40 mm when the average is 100 mm to 150 mm

Percentage retained on 5 mm sieve – 6% Density of air-free mortar – 1.6% Compressive strength, average 7-day strength – 7.5%

h) All the material for the concrete shall pass the specification

requirements and concrete shall be verified with DM-DCL

3.14.2 Pumping Concrete

Pumped concrete is defined as concrete that is conveyed under pressure either through rigid or flexible hose, and discharged directly into the desired area. Pumping may be used for almost all concrete construction but is especially useful where there is inadequate space for other concrete placing equipment to be operated.

A steady supply of pumpable concrete is necessary for satisfactory pumping. Pumpable concrete, like conventional mixes, requires good quality control; ie, properly graded uniform aggregates, and materials uniformity and consistently batched and thoroughly mixed.

3.14.3 Field Control

Quality concrete in the field is the ultimate objective to be attained; a high level of quality control must be maintained. The locations at which samples for testing the concrete are taken is extremely important. Sampling according to ASTM C94, is for the acceptability of the ready-mixed concrete. However, the quality of the concrete being placed in the structure can only be measured at the placement end of the pipeline. Where appropriate, sampling at both the truck discharge and point of final placement should be employed to determine if any changes in the slump, air content, and other significant mixture characteristics occur. When sampling at the end of the placement line, great care should be taken to ensure that the sample is representative of the concrete going into the placement. Changing the rate of placing and/or the boom configuration can result in erroneous test results.

3.14.4 Remixing

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Fresh concrete that is left to agitate in the truck mixer tends to stiffen before initial set develops. This concrete shall not be used if the following conditions apply; (1) the maximum water to cement ratio will be exceeded, (2) the maximum slump will be exceeded, and (3) the maximum number of revolutions or mixing time to placement time will be exceeded.

3.14.5 Documentation

The Engineer shall receive copies of the delivery tickets for each batch of concrete, and have access to a site record book maintained by the Contractor in which the following information is recorded for each batch of concrete delivered:-

(i) Delivery ticket number.

(ii) Slump of the concrete, testing on site immediately prior to placing.

(iii) Time when concrete is placed in position and left undisturbed. (iv) Location that the concrete is placed. (v) Works test cube reference.

3.15 REINFORCEMENT STEEL

3.15.1 General

This work shall consist of furnishing, fabricating and placing steel

reinforcement bars of the grade, type, quality, size, shape and quantity

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designated, all in accordance with these Specifications and the details shown on the Drawings.

The Contractor shall be responsible for furnishing reinforcing steel in

sufficient quantity and of the proper sizes, lengths and shapes shown on the Drawings for any given structure.

3.15.2 Material Specifications

All reinforcement bars shall be of a deformed type in accordance with

BS 4449, except that plain bars may be used where specifically indicated on the Drawings. Plain bars shall be in accordance with BS 4449.

All steel reinforcement shall conform to the requirements of the

Specifications for Deformed High Yield Steel Bars, Grade 460 Type 2, unless otherwise shown on the Drawings or specified by the Engineer.

Mild steel where specified or called for shall be either deformed or plain

bars complying with ASTM A615 structural grade or BS 4449 or any equivalent National Standard as directed and approved by the Engineer.

Tying wire shall be No.16 gauge soft annealed iron wire or No. 18

gauge stainless steel wire or the equivalent AASHTO specification for tying wire.

Welded wire fabric shall be used as reinforcement for concrete where

shown on the Drawings and as directed. Welded wire fabric shall conform to the requirements of AASHTO M55 or to BS 4483.

All reinforcement shall be protected against corrosion with a fusion-

bonded epoxy coating in accordance with the requirements of ASTM A775/A775M and BS 7295.

The Contractor shall be responsible for obtaining the Engineer’s

approval to the steel bars prior to coating commencing. Such approval will in no way relieve the Contractor of his responsibilities under the Contract.

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The frequency of sampling and method of quality control shall be in accordance with BS 4449 latest edition.

For steel reinforcement, please refer to clause 4/8 “Reinforcing Bars” of

Section 4 – Concrete Works of DM Roads Dept. General Specification. The Contractor shall furnish to the Engineer a certificate of compliance

for each shipment of coated steel bars. The certificate of compliance shall state that representative samples of the coated bars have been tested and that the test results comply with the requirements of the Specifications.

3.15.3 Construction of Reinforcement

Steel reinforcing shall be stored on timber packing clear of the ground.

The steel bars shall be free from sharp deformations, rolled-in silvers, deep recesses or surface faults/blemishes which could result in inefficient or inadequate coating. When fixed in the work and immediately prior to concreting, steel reinforcing shall be entirely free from loose mill scale, loose rust, oil, grease, paint, mould oil, and all other deleterious and extraneous material. All hooks, bends, etc., unless otherwise shown on the Drawings shall be to BS 4466.

Before ordering reinforcing steel, the Contractor shall prepare bar

bending schedules at his own cost and submit them to the Engineer for his approval. Bar schedules shall show the weight of each bar, the total weight of each bar size and the total weight of bars, and bending diagrams for bars in accordance with BS 4466. The length of each bar shall be calculated in accordance with BS 4466 except that the minimum internal bending radius shall be four times the bar diameter.

The Contractor shall also provide and submit to the Engineer for approval any working drawings additional to the Contract Drawings which may be found necessary for the production of bar bending schedules or for the completion of the Works.

The Engineer’s approval of the Contractor’s working drawings and bar

bending schedules shall in no way relieve the Contractor of responsibility for the correctness of such drawings or schedules.

Steel reinforcement shall be bent accurately to the shapes and

dimensions shown on the approved bar bending lists or drawings. Bars shall be bent round mandrels of the requisite diameter.

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Steel reinforcement shall be cut and bent in accordance with BS 4466.

Cutting or bending by the application of heat is not permitted. Welding of reinforcement shall only be permitted when approved in writing by the Engineer. If such approval is given then the workmanship shall be in accordance with BS 5135. The Contractor shall submit full technical details of his proposed procedures prior to seeking approval.

Hot rolled high yield bars shall not be straightened or bent again, having

once been bent. If the Engineer gives approval to bend mild steel reinforcement projecting from the concrete, the internal radius of bend shall not be less than four times the nominal size of the bar.

Links, hoops, stirrups are generally to be bent round pins of the same

diameter as the bars they are to embrace. Where however, such bars are less in diameter than twice the diameter of the link, the radius of the bend shall be equal to the diameter of the link.

3.15.3.1 Placing Reinforcement

The number, size, form and position of all reinforcement shall, unless

otherwise directed or authorized by the Engineer, be strictly in accordance with the Drawings. Nothing shall be allowed to interfere with the disposition of the reinforcing bars. Bars generally must be of the required lengths. Welding of the bars will not be permitted. Lapping of the bars other than the lap splices shown on the Drawings should be avoided. The Engineer may approve certain lappings under special conditions. All lappings should comply strictly with the AASHTO specifications, namely Article 1.5.6. Clause "c".

The steel reinforcement shall be firmly held in position by wire ties and

concrete blocks or other approved spacers designed to maintain the correct clear cover of concrete over steel reinforcement. They shall be as small as possible consistent with their purpose, and of a shape acceptable to the Engineer. Minimum cover to reinforcement shall be 50 mm unless otherwise detailed. The position of spacers and their method of use shall be approved by the Engineer. The steel reinforcement shall be so connected as to form a rigid cage.

All intersecting bars shall be bound together with No.16 gauge soft iron

wire with the ends of the wire turned into the main body of the concrete.

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3.15.3.2 Maintaining Reinforcement in Position Concrete distance blocks shall, unless otherwise directed, be used

between the reinforcement and the bottom and sides of the forms to ensure correct placing and cover of the bars. The strength of such concrete distance blocks shall be not less than that of the main concrete. The greatest care shall be taken to prevent any displacement or bending of the members of the reinforcement adjusted and temporarily fixed in position before commencement of the concreting. Reinforcement temporarily left projecting from the concrete at construction of other joints shall be adequately protected against displacement both during concreting and afterwards and shall not be bent out of position unless agreed by the Engineer's Representative. During the concreting competent steel fixer shall be in attendance to re-set any reinforcement inadvertently displaced.

3.15.3.3 Approval of Reinforcement Before Concreting

The Contractor shall in all cases request the approval of the Steelwork

by the Engineer's Representative in sufficient time to allow an inspection to be made and shall not commence concreting until such approval is obtained. The period between the Contractor's request for approval and his intention to commence concreting shall not be less than one clear normal working day and the Engineer's Representative may require a longer period if, in his opinion, the reinforcement is of such complexity as to require it.

Such approval shall not absolve the Contractor of his responsibilities

under the Contract. 3.16 PRECAST CONCRETE KERBS, EDGINGS & QUADRANTS

Precast concrete kerbs and edgings shall be hydraulically pressed and they and precast concrete quadrants shall comply with the requirements of BS 7263: Part 1 and to the dimensions and shapes shown on the Drawings and/or as directed by the Engineer. They shall be Class B concrete with sulphate resisting cement as indicated in Clause 3.2.7 of

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this Specification. They shall be uniform in colour free from cracks, flaws or other defects with well defined arises. The kerbstones shall be 900 mm long or as directed by the Engineer's Representative. Samples of kerbstones proposed to be used shall be submitted to the Engineer for his approval prior to order or manufacture. Kerbstones shall not be used before they have been inspected and approved by the Engineer. They shall be fully cured when delivered to site (28 days min.). Kerbstones shall be laid on concrete Class C bedded on 1:3 sand cement mortar as specified and/or as directed by the Engineer. All kerbstones shall be well bedded and settled in place true to line and level with a suitable wooden mould. Before kerbstones shall be approved it should be ensured that their top surfaces are in a uniform plane and their front faces are in correct alignment. Any kerbstones not satisfying these requirements or having cracked or broken arises or faces shall be removed and replaced or reset as instructed by the Engineer. Joints between kerbstones shall be not less than 3 mm nor greater than 5 mm in width and shall be uniform from top to bottom. Joints shall be left open. Where precast kerbs of straight section are laid to form radii, joints should be filled with non-shrinkage mortar, and expansion joints (using flexel or similar joint filler) shall be provided at 3 m centres. For radii of 10 m or less quadrants shall be used. Kerbs of a reduced size shall only be used for this condition where approved by the Engineer. Tolerance in top level of kerbstones and horizontal alignment shall be ± 3 mm. All kerbstones shall be painted alternately black and white. The paint shall be an approved concrete paint giving a nominal thickness of 100 microns in two applied coats. Tranverse strength and Water Absorption shall be in accordance with BS 7263 : Part 1.

3.17 IN-SITU CONCRETE EDGING

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In-Situ concrete edge strips shall be to the cross section shown on the drawings and the class of concrete made with sulphate resisting cement indicated thereon in accordance with Clause 3.2 of this Specification. The edge strip shall be formed in as long lengths as possible and the form work shall be set on the top surface of the sub-base, set to produce the line and level in accordance with the requirements of this Specification. Care must be taken to ensure that the top surface is carefully finished to achieve these requirements and to provide the control of the wearing course. Expansion joints will be provided with an approved joint filler at maximum 3 m centres as shown on the drawing and/or as directed by the Engineer. The kerb shall be protected against covering or splashing by bitumen or cement.

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SECTION 5

BRICKWORK AND BLOCKWORK

5.1 MATERIALS 5.1.1 Concrete Bricks and Blocks

Concrete bricks and blocks shall be constructed from Class B (sulphate resisting Portland Cement) concrete but the coarse aggregate shall be 10 mm to 5 mm. The blocks shall be cast in clean oiled moulds.

They shall be free from cracks, uniform in size, true to shape, free from

deleterious matter, clean, hard, impervious with smooth faces in appearance similar to normal Class B concrete and with well defined arises.

Bricks and blocks shall not be incorporated into the Works until they have

matured under suitable conditions for 28 days.

5.1.2 Bricks Engineering bricks and special purpose bricks such as radial bricks, weir

bricks, copings and bull nosed bricks shall have an average compressive strength of at least 69 N/mm2 and an average absorption not exceeding 4.5 percent by weight measured by a standard boiling or vacuum method.

Faces of engineering bricks to be exposed to the weather or liquids shall not

be wire cut. Bricks for arches and circular work of 1.5 metres and less in diameter shall

be purpose made radial bricks.

5.1.3 Sand for Mortar Sand for mortar shall comply with the following table:-

Table 5-1. Sand for Mortar Percentage by mass passing sieve

Sieve Size Rendering Brickwork/General Purposes 5.00 mm 100 100 2.36 mm 90 - 100 90 - 100 1.18 mm 70 - 100 70 - 100

600 microns 40 - 80 40 - 100 300 microns 5 - 40 5 - 70 150 microns 0 - 10 0 - 15

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5.1.4 Lime for Mortar Lime for cement-lime and lime-sand mortar shall be the hydrated type to the

approved standard.

5.2 CONSTRUCTION

5.2.1 General Bricks and blocks shall be properly stacked on level hardstanding. Broken

blocks shall be removed from the site. Bricks shall be adequately protected from inclement weather. During hot and dry weather bricks and blocks shall be wetted as necessary

and the tops of walls shall be wetted before a course is laid All faces of brickwork or blockwork will be kept clean and no rubbing

down of exposed faces will be permitted. Vertical faces of all bricks shall be well buttered before being laid and the

whole well grouted at each course. Brickwork and blockwork should be built in a uniform manner. Corners and

other advanced work should be raked back and not raised above the general level more than 1.0 m at one lift.

All blocks shall be laid on even full beds of mortar; vertical faces of all

blocks shall be well buttered before being laid and the whole well grouted at each course.

The overall dimensions of four blocks laid in mortar shall not exceed by

more than 25 mm the overall dimensions of the same blocks laid dry. 5.2.2 Engineering Brickwork

Unless otherwise specified or ordered all engineering brickwork shall be

built in English bond. In all engineering brickwork the overall dimensions of four bricks laid in

mortar shall not exceed by more than 25 mm the overall dimensions of the same bricks laid dry.

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When concrete is to be faced with brickwork, header bricks shall be built into every fourth course and at intervals of 2 bricks horizontally so as to project 1/2 brick into the concrete. Headers in successive courses shall be staggered.

5.2.3 Blockwork All blockwork shall be built level, plumb and true to line with all perpends

in line vertically. Blockwork shall be built in stretcher bond and alternate courses shall be bonded in at all junctions. All blockwork shall be set in gauged mortar as described to the lengths, heights and thicknesses shown on the drawings. Fair and fair-faced work shall be kept perfectly clean and no rubbing down of blockwork will be allowed. Blockwork to be plastered shall have joints struck off flush and left rough.

5.2.4 Cement Mortar

Mortar for precast concrete units, brickwork and blockwork shall be gauged

in the proportions of one part of cement to three parts of sand. Lime shall only be added if specifically ordered.

Cement mortar shall be mixed on a clean surface in small quantities

sufficient only for 30 minutes work and shall not be remixed or worked up again after setting or hardening; any mortar that has become set or hard shall be rejected and removed from the site.

Ingredients shall be measured in proper boxes and shall be turned over and

thoroughly mixed on a wooden platform.

5.2.5 Cement Lime Mortar Cement lime (gauged) mortar shall consist of one part Portland Cement, one

part of lime and six parts of sand by volume (1:1:6). All materials shall be accurately gauged using gauge boxes and shall be thoroughly mechanically mixed. Mortar that has begun to set shall not be revived or re-used.

5.2.6 Cement Mortar Rendering

Cement mortar rendering shall consist of two or more coats; the undercoat

shall be 13 mm thickness and scored to form a key for the final coat which shall be not less than 6 mm in thickness. The finished coat shall be worked with proper metal floats, and the face left with an even and polished surface. The mortar for the undercoat of the rendering shall be gauged in the

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proportion of one part of cement to three parts of sand, and the finished coat shall be in the proportion of one part of cement to two parts of sand.

For at least 24 hours before rendering is applied the concrete or brickwork

face or previous coat of rendering shall be thoroughly soaked with water, and the finished rendering shall be watered at least four times a day and kept damp for a period of a least fourteen days after completion. Not more than three days shall elapse between the application of one coat and its being covered up with a second or finishing coat. All arises shall be sharp and linear.

When rendering is to be applied to brickwork, the joints shall be raked and

cleaned out to a depth of 13 mm.

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6.1 CLEANING AND INSPECTION OF PIPELINES

The Contractor shall ensure during and after construction that the pipes remain

clean and free of all silt, mortar, debris and other obstructions, and if required by the Engineer, the pipelines shall be cleaned out using approved methods and equipment which do not damage the internal lining of the pipes and manholes. When work is not in progress the open ends of the pipeline shall be securely plugged with an approved watertight plug or stopper to prevent the ingress of deleterious matter into pipelines.

After backfilling pipe trenches and completing chambers, hatch boxes, etc.,

and before the trench surfaces are reinstated, the interior of pipelines shall be cleaned of silt and debris by approved methods for inspection by the Engineer's Representative as follows:-

All newly constructed pipelines of 600 mm (nom.) internal diameter and

smaller shall have a loose plug passed through them to show that they are clear of obstruction and free from deflection. The loose plug shall be dimensioned to suit the permissible minimum deflected diameter of the pipe. Alternately, a deflectometer capable of measuring diametric dimensions both vertically and horizontally may be used as specified in Clause 4.4.8.

All newly constructed pipelines greater than 600 mm (nom.) internal diameter

will after cleaning be inspected from the inside and the Contractor shall provide a suitable trolley for this purpose.

All renovated or replaced pipeline shall after cleaning, be inspected from the

inside using CCTV inspection as specified in Section 13. In addition gravity pipelines or sewers shown as straight lines between

manholes on the drawings shall be subjected to a light sighting test as detailed in the pipelaying specification Clause 4.4.3.

Pipelines, manholes, chambers/structures will be inspected again before being

put in service or taking over (whichever is sooner) and if required by the Engineer's Representative shall be cleaned again in whole or in part by suitable means which may include, if directed, flushing with clean water.

6.2 TESTING OF PIPELINES

6.2.1 General

The Contractor shall make his own arrangements for the supply of water used

for testing and cleaning of pipelines which shall be obtained from a source approved by the Engineer. All water required for testing and cleaning shall be provided by the Contractor at his cost.

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Prior to commencement of flushing or testing, approval shall be obtained to the methods and programme for testing and to the method of disposal of all fluids used for flushing or testing purposes. Under no circumstances will permission be given for the discharge of such fluids into the existing sewerage system.

If permission is given to use new or existing pipelines or culverts which are not

part of a live system, they shall be thoroughly cleaned of all silt and any resulting damage made good after use.

If lagoons for the storage of such fluids are permitted, they must be suitably protected with fencing and attended by day and night to prevent access by the general public and will not be sited adjacent to buildings. Approved means of preventing the formation of mosquito larvae on the surface of the lagoons will be employed.

Testing of pipelines shall in all cases be applied in the presence of the

Engineer's Representative. The Contractor shall notify the Engineer at least 48 hours before hand of his intention to test a section of pipeline. The Contractor, at his own expense, shall provide complete plant and all struts, thrust blocks, etc., as may be necessary for effectively testing the pipelines to the specified pressures.

Pipelines shall be properly completed and supported before being put under

test. No testing will be permitted until seven days after thrust blocks and other holding down works have been completed.

For both gravity and pressure pipelines only testing of new, renovated, or

replaced sections of pipelines and fittings will be required under the Contract, in accordance with this Specification, unless detailed otherwise. Such testing will be carried out before making final connections to the existing network. However where tees or other fittings are inserted into existing pipelines and where lengths of pipeline are replaced no backfilling will be allowed at the tees or fittings or at the joints between new and existing pipework until the pipeline has been returned to service and a visual inspection of all such fittings and joints made at the network pressure.

Should any inspection be unsatisfactory or any test fail the Contractor shall

replace defective pipes, leaking joints or otherwise re-execute defective work as instructed following which cleaning and testing will be repeated until the Engineer's Representative certifies the pipeline to be satisfactory.

6.2.2 Testing of Non-Pressure Pipelines

All non-pressure pipelines of 600 mm nominal diameter or smaller shall be

given a preliminary air test when the pipeline is bedded and jointed before backfilling and a final water test after backfilling in the presence and to the satisfaction of the Engineer.

Unless otherwise instructed non-pressure pipelines shall be tested in sections

between manholes.

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Preliminary and final air and water tests will not normally be applied to pipelines greater than 600 mm (nom.) internal diameter and acceptance of these pipelines will be dependent on satisfactory visual inspection of the pipes and joints.

Air Test (Preliminary Test)

After a length of pipeline is bedded and jointed, and before backfilling, it shall

be given a preliminary test as detailed below:

1. The Contractor shall plug all pipe outlets with suitable plugs, and brace each plug securely where needed.

2. Air shall be pumped in slowly to the pipe until a pressure of 100 mm head of water is indicated on a manometer connected to the system.

3. After the internal pressure of 100 mm is obtained, two minutes shall be allowed for the air temperature to stabilize within the pipe.

4. Air may be added to restore the pressure to 100 mm. 5. During a further period of 5 minutes (without further pumping of air) the

pressure should not fall below 75 mm. 6. Release of the air pressure shall be carried out by removal of the stopper at

the end of the pipeline away from the manometer which will remain connected. Failure to carry out the air pressure release in this manner shall render the test invalid.

7. The Contractor will not be permitted to commence testing later than 4 hours after sunrise or earlier than 4 hours before sunset during the summer period unless otherwise directed by the Engineer.

Water Test (Final Test)

After backfilling the length of pipeline under test, it shall be given the

following final test: 1. All branches and open ends shall be closed with suitable stoppers, secured

with longitudinal braces before testing commences. 2. Water shall be filled from the lowest point and air allowed to escape. No

entrapped air shall remain in the pipeline while testing. 3. An internal pressure equivalent to a head of water of depth to invert of the

pipeline plus 1.25 m, or 4 m head whichever is greater shall be maintained for 30 minutes to allow for initial absorption of water.

4. After that, the test pressure shall be maintained for 60 minutes and water added shall be measured.

5. Pipeline shall be treated as passed if water consumption in 60 minutes does not exceed 7.5 litres per metre of diameter per 30 m of length of pipeline under test.

Where in the opinion of the Engineer's Representative the above test is not sufficiently indicative of water tightness by reason of high ground water levels the test will not be applied. Acceptance of the pipelines will then depend on satisfactory inspection or testing for infiltration as referred to below, and air test of the pipeline in manhole lengths.

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The Engineer may require any length of pipe suspected of being damaged to be retested by the water test at any time during the contract period.

Infiltration Test

After completion of backfilling and restoration of normal subsoil conditions, all gravity pipelines and manholes shall be examined for infiltration as follows:

1. All inlets to the system shall be closed to prevent the entrance of water. 2. Pumping of groundwater shall be discontinued for at least 3 days prior to

the test for infiltration. 3. The section of the pipeline under test, including manholes, shall be

accepted as satisfactory if the infiltration does not exceed 1.00 litre per hour per metre of pipe line per metre of nominal internal diameter.

Notwithstanding the satisfactory completion of the infiltration test, if there is any discernible flow of water entering the pipeline at a point which can be located either by visual or closed circuit television inspection, appropriate measures shall be taken to stop such infiltration.

6.2.3 Testing of Pressure Pipelines

All pressure pipelines of 675 mm or more internal diameter shall have each

joint individually tested by means of an approved joint testing apparatus.

Pipelines of less than 675mm shall be subjected to a preliminary air test as soon as a length of pipe has been laid and before backfilling. Pressure pipelines shall then be given a final test using water after they have been backfilled, cleaned and inspected.

Preliminary pressure testing of pipelines may be carried out if so required by

the Engineer with partial backfill only and exposed joints, but the stability and safety of the Works must be ensured at all times.

Each test shall be restricted to pipes of one class. Pipelines shall be tested in

sections not exceeding 500m or between valve positions. In addition the whole pipeline shall be tested upon completion. Particular care must be taken to isolate air valves, etc., not to apply higher pressure than specified at any point on the pipelines and to ensure that the pipelines are adequately anchored before any test is carried out.

Gauges used for testing pressure pipelines shall be capable of reading

increments of 0.1m head. Before any pressure gauge is used, the Contractor shall arrange for it to be checked independently and a dated certificate of its accuracy shall be provided to the Engineer. Calibration of pressure gauges shall be carried out at regular intervals as required by the Engineer

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Air Test (Preliminary Test)

As soon as a length of pressure pipe has been laid and before backfilling, when applicable and when ordered it shall be subjected to the following preliminary test:

1. The Contractor shall plug all pipe outlets with suitable plugs, and brace

each plug securely where needed. 2. Air shall be pumped in slowly to the pipe until a pressure of 300 mm head

of water is indicated on a manometer connected to the system. 3. After the internal pressure of 300 mm is obtained, two minutes shall be

allowed for the air temperature to stabilize within the pipe. 4. Air may be added to restore the pressure to 300 mm. 5. The test will not be satisfactory if the air pressure falls to less than 275 mm

during a period of 5 minutes without further pumping of air. Water Test (Final Test)

Pressure pipelines shall be given the following final test using water after they have been backfilled, cleaned and inspected:

1. All the joints of the pipeline shall be left open for the purpose of inspection

for leakage if any, where practicable or instructed by the Engineer. 2. Pipe ends shall be closed with suitable stoppers, secured with longitudinal

braces/thrust block, before testing commences. 3. Water shall be filled slowly (to prevent possible water hammer) from the

lowest points and air allowed to escape through an air vent fixed for the purpose at the highest points of the pipeline section under test. No entrapped air shall remain in the pipeline while testing.

4. Pressure in the pipeline shall then be raised steadily upto and maintained at the rated pressure for a period of 30 minutes to allow for absorption and achieve conditions as stable as possible for testing.

5. If no leakage has been observed, pumping shall then be resumed and the pressure slowly raised to the specified test pressure.

6. Unless specified elsewhere or directed otherwise by the Engineer, the test pressure shall be 900 KN per square metre (91.8 m head of water).

7. Test pressure shall be continuously maintained by the use of the pump for a period of 60 minutes and the amount of makeup water required to maintain the pressure shall be accurately measured (to the nearest 1/8 litre).

8. Pipeline shall be deemed to have passed the test if all the following conditions are satisfied:

i. No water is visible coming out of the pipe or joints at any point; ii. Amount of make-up water required does not exceed 1 litre per hour

per 100 mm diameter per kilometer of pipeline under test; iii. The loss of the pressure during the test period does not exceed 70KN

per square metre. 6.3 TESTING OF VALVES

Valves and all pipelines appurtenances shall be hydraulically tested together with the pipeline in which they are installed. Valves shall be tested for

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operation under working pressure and shall be adjusted so that they operate smoothly, seat properly and are installed to tolerances recommended by the manufacturer.

6.4 TESTING OF RENOVATED AND REPLACED PIPELINES

All non-pressure pipelines renovated or replaced by slip lining, soft lining, or pipe bursting methods shall be given an air test or water test per Clause 6.2.2 in the presence and to the satisfaction of the Engineer.

6.5 TESTING OF WATER RETAINING STRUCTURES

All water retaining structures shall be visually inspected to confirm that there is no infiltration. Where it is required by the Engineer, water retaining structures shall be tested for watertightness. The structure shall be filled with water and shall stand for a period of three days, to allow for absorption. The structure shall be considered satisfactory if, subsequent to this period, there shall be no fall in level over a period of 24 hours (after making the allowance for rainfall and evaporation) and there shall be no visible leaks, or damp surface areas. This shall be carried out before any backfilling and before the application of any external concrete protection has taken place. Any damages revealed as a result of such tests shall be made good to the satisfaction of the Engineer.

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9.1 MATERIALS 9.1.1 Corrosive Environments Corrosion protection systems and surface coatings shall in all cases be suitable

for exposure to their contact with environmental conditions which may include any or all of the following :-

(1) The climatic conditions prevailing in the project area with particular

emphasis on temperature variations, high surface temperatures and high humidities.

(2) Septic sewage with a pH value of less than one. (3) Sulfuric acid solution in sewage slimes in concentrations up to 15 % by

weight. (4) Hydrogen sulfide and other gases emanating from sewage, septic sewage

and sewage sludges. (5) Saline groundwater with high chloride or sulphate contents both below

the water table and in soil zones above the water table where capillary action and the presence of oxygen may cause extremely severe conditions.

(6) Wind blown chlorides. (7) Wind blown abrasive sands.

9.1.2 Paint

Protective and decorative paint systems including primers and undercoats shall be obtained ready mixed for use. All containers of paints and other coating systems shall show date of manufacture, shelf life and pot life where applicable. Paint shall be applied as per Clause 9.2.2 (refer to Clause 19.4 for schedules of protective coatings and surface preparations). The Contractor shall only be allowed to use paints which are delivered to the site in sealed cans or drums bearing the name of the manufacturer and properly labeled. Tints and shades of final coats shall be advised by the Engineer or his Representative.

9.1.3 Impervious Tanking Membrane

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Membrane used for tanking to concrete structures shall be impervious, self-adhesive and covered with a release agent. Rubber bitumen/PVC membrane shall have a minimum bitumen thickness of 2.0 mm and PVC thickness of 0.3 mm.

9.1.4 PVC Sheet Lining Materials

PVC sheet materials to be used for lining concrete structures and pipelines internally shall be manufactured from polyvinyl chloride, plasticisers and pigments to make permanently flexible sheets. The colour of the sheet shall be approved on site. The PVC sheet shall have a minimum thickness of 1.5 mm and shall be formed by extrusion to have on one side locking keys or ribs of either ‘T’ or diamond section at centers not greater than 75 mm. It shall be capable of forming a continuous 100% effective seal with the use of welding strips or other approved method and shall be supplied with all materials and tools for making the joints. The tensile strength of the material shall be not less than 17000 kN/m2. All weld strips, patches and other sheets used in the permanent fixing of the ribbed sheet shall be of a material having the same composition as the ribbed sheet.

9.1.5 Reinforced Plastic Liners Reinforced plastic liners to be used for lining pumping stations and manholes shall be manufactured (as per Clause 19.1.4) to the dimensions given on the Drawings, within the following tolerances :- (1) The work size, which is defined as the internal diameter as specified by

the manufacturer, shall be declared and shall not differ from the normal diameter by more than ± 1%.

A manufacturing tolerance on the work size of 10 mm will be allowed

provided that a tight fit is achieved between the liner and the slab liner. (2) Liners shall be supplied in lengths to suit requirements with a resin-rich

finish to internal surfaces.

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(3) Minimum thickness shall be 7 mm for sewerage work and 5 mm where approved for drainage work.

(4) The out of squareness shall not be greater than 10 mm. (5) The deviation from straightness of the bore of the liner shall not exceed

20 mm. Although the liners are not designed to be structural, they shall have a sufficient stiffness to withstand :- (1) Buckling or distortion in transit or storage. (2) A hydrostatic head of 8 metres without distortion damage, leakage or

permeation. (3) Grouting pressures. Prior to grouting of the manhole liner at least 24 hours shall be allowed for temperature equalization between the manhole structure and the reinforced plastic liner. The manufacturer shall provide shop drawings of the proposed top slab liners prior to manufacture for approval. The manufacturer shall stipulate the maximum deflection of the slab liner permitted without causing surface cracking to the gel coat. The Contractor must take care not to exceed this limit, and any surface cracking that occurs will be repaired.

9.1.6 In-Situ Laminations The Contractor shall apply either of the following systems of laminations to renovate the manholes: (1) Epoxy resin mortars and laminating systems. (2) Lamination using glass chopped strand mats impregnated with

isophthalic resin and with vinylester resin. (3) Bisphenol polyester resin with heavy duty glass cloth inclusion.

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Epoxy Resin System A mortar consisting of an epoxy resin and hardener shall be mixed with a filler material to produce a thixotropic dense trowel suited mix. The mortar shall be manually applied to all internal surfaces and left at least 15 minutes. A minimum of 7 mm of GRP laminate shall then be applied in two layers. The benching laminate shall be sealed on to the in-situ channel liner with an approved compatible material. The top surface of the benching shall be treated to produce a non-slip finish. Isophthalic and Vinylester Resin System Firstly the surface of the manhole walls and the surface of the cover slab soft, benching and channel (concrete) shall be coated with isophthalic resin. Three layers of 600 gm/m2 glass chopped strand mat shall then be applied and impregnated with isophthalic resin to provide an approximate thickness of 5 mm. Next one layer of 600 gm/m2 and one layer of 300 gm/m2 glass chopped strand mat shall be applied and impregnated with vinylester resin. Following this two layers of glass veil shall be applied and impregnated with vinylester resin. Finally a coating of vinylester resin with paraffin wax shall be applied to provide a total minimum thickness of 7 mm. Bisphenol Polyester Resin with Heavy Duty Glass Cloth Inclusion System All cleaned surfaces shall be primed with a polyester based primer to seal the surface and aid the application of the lining. The base coat of resin reinforced with filler shall be trowel applied to approximately 1.5 mm thick. The reinforcing cloth shall be consolidated into the first trowel coat with particular attention being paid to ensure that the cloth is fully wetted out. This application shall be allowed to cure overnight before applying the top coat of resin. This resin reinforced with the same filler shall be troweled on and dressed with a rolling aid.

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9.1.7 Epoxy Mortar

Where indicated on the drawings or specified to use epoxy mortar for benching and channels in any manhole or any other structure such as chambers, pump station wet-well, etc., they shall be formed to have a min. of 10 mm thickness of an approved epoxy-resin mortar system.

The epoxy mortar system shall be a trowellable, two component epoxy resin

system consisting of a prefilled base and unfilled reactor which when mixed shall produce a high strength, impermeable and chemically resistant mortar.

The epoxy mortar system shall have excellent chemical resistance to sodium

chloride and sulphuric acid (shall pass the relevant chemical resistence test), and shall have high impact resistance. Typical properties are given in the following table:

Table 3-7. Properties of Two Component Epoxy Mortar

Property

Test Method Limit

Sag at 10 mm thickness - None Working Time ASTM C308 > 90 min. at 25°C Full Cure at 25°C - 3 to 7 days Setting Time at 25°C - 30 to 45 min. Water Absorption ASTM C413 < 0.07 % Compressive Strength BS 6319:Part 2 > 40 N/mm2 at 25°C,

7 days cure Flexural Strength BS 6319:Part 3 > 3 N/mm2 at 25°C,

7 days cure Tensile Strength BS 6319:Part 7 > 8 N/mm2 Bond Strength BS 6319:Part 4 > 30 N/mm2 Density BS 6319:Part 1 1750 kg/m3

When placed on a concrete substrate the epoxy mortar system shall have an

adhesive strength of not less than the internal cohesive strength of concrete. To achieve the necessary adhesion to the substrate an epoxy primer compatible

for use with the mortar and the substrate shall be applied. The epoxy mortar, or the primer where required, shall be suitable for application

onto a substrate with a moisture content of 4% or less as measured by the "wet-check" Moisture Meter or other instruments approved by the Engineer.

The pot-life of the mixed mortar shall not be less than one hour at the temperature at the place of application at the time of mixing. The Engineer may

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restrict application to such time as the ambient temperature is sufficiently low for the specified pot-life to be ensured.

There shall be strict control of surface cleanliness between primer and epoxy

mortar and between coats of the same. Vacuum removal of dust and sand shall be employed and water soluble contamination shall be removed as specified above. Where dirt or dust has become trapped in the primed surface it shall be removed with suitable abrasive paper. The surface being primed shall be free of visible moisture throughout these operations.

The mortar manufacturer shall stipulate primer and epoxy re-coat intervals for

all curing temperatures likely to be encountered and these shall be adopted with a maximum tolerance of +4 hours. Where this is exceeded the surfaces to be re-coated shall be suitably abraded to remove gloss.

Mixing of the components shall be strictly in accordance with the

Manufacturer's recommendations and care shall be taken to avoid the entrainment of air in the mixes.

Wet thickness gauge shall be used by the mortar applicators continually to

check that sufficient mortar is being applied to achieve the required dry thickness.

9.1.8 Bituminous Emulsion

Bituminous emulsion shall be to the approved standard and shall not contain less than 53 % of bitumen.

9.1.9 Waterproof Paper Waterproof building paper shall be to the approved standard. For roadworks it shall be Class B.

9.1.10 Protective Materials for Wrapping Pipeline Components

The protective materials for wrapping pipeline components shall comprise a rust inhibiting compound for the bolts, a mastic or comparable filler which will not harden for moulding over the assembly, and a waterproof tape for wrapping.

9.1.11 Approved Paint Suppliers

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The following paint systems have been successfully used in sewage environments in Dubai. Reference to these systems in no way precludes the use of similar or superior systems by other suppliers. Supplier Paint System 1. Colebrand Limited Epoxy Prefabrication Primer: CXL 100. Colebrand House Epoxy Resin Solvent Free Coating : CXL 115. 20 Warwick Street High Build Epoxy Airless Spray Coatings. Regent Street CXL 141 for temperate climates applications. London WIR 6BE CXL 140 for hot climates applications. England 2. Corroless International Limited Corroless T. Berk House, Basings View Corroless Epoxy. Basingstoke Hampshire RG 21 2HW England

9.2 INSTALLATION OF PROTECTIVE COATINGS AND LINERS TO CONCRETE

9.2.1 General Concrete structures shall be protected both internally and externally where indicated on the Drawings and by the methods detailed.

9.2.2 Protective Coatings/PVC Liners All protection systems shall be applied strictly in accordance with the manufacturer's instructions, two copies of which shall be included with the Contractor's application for the approval of the material, and when approved will be deemed to be part of this specification unless stated otherwise. The permissible rate of permeation of all protection systems shall not exceed 0.0027 per inches (ASTM, 1 per inch = 1 gramme of water per hour per square foot (0.0929 m2) per mil (0.0254 mm) of thickness for a 1 inch (25.4 mm) difference in Hg vapour pressure on each side of a membrane. Coatings shall not be applied at expansion, contraction or construction joints which incorporate a sealant. (1) External Buried Surfaces

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The external surfaces of concrete substructures shall be protected or "tanked" by one of the following methods which will be indicated on the Drawings. a) An approved impervious bituminous waterproof membrane:

The membrane shall be tropical grade, cross laminated to have high tear strength; and puncture and impact resistance and shall be chemically resistant for protection against aggressive soils and contaminated groundwater.

The membrane shall comply with the following :-

Property

Test Method Typical Results

Tape Strength

ASTM D638

Long 4.2 N/mm2

2

Trans 4.8 N/mm2 Tensile Strength

ASTM D638

Long 42 N/mm2 Trans 48 N/mm2

Elongation Film

ASTM D638

Long 210 % Trans 160 %

Tear Resistance

ASTM D1004

Long 340 N/mm2

2

Trans 310 N/mm22

Adhesion to Self Concrete

ASTM D1000

1.8 N/mm2

Puncture Resistance

ASTM E154

220 N 65 mm2

2

Water Resistance : After 24 hours After 35 days

ASTM D570

0.14 % 0.95 %

Environmental Resistance

ASTM D543

Conforms

Moisture Vapour Transmission Rate

ASTM E96

0.3 g/m2

2/24 hrs.

The membrane shall be laid on to smooth concrete blinding surface free

from sharp edges and projections and on to walls primed with an approved primer and applying the performed membrane, sticky side downwards, laid strictly in accordance with the manufacturer's instructions. The minimum over laps shall be 50 mm side and end.

During the backfilling operation around all tanked structures, the waterproof membrane shall be protected from damage by the use of an

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approved protection board. The board shall be manufactured from graded and selected kork granules bound with modified bitumen and encased between two layers of tough asphalt paper. The board shall be light weight and capable of providing protection against abrasive backfilling. The board may be stored outside, but shall be kept flat on original pallets.

b) A brush applied bituminous emulsion: The surface shall first be wire brushed and all dust and loose scale

removed. Three coats of bituminous rubber emulsion paint shall then be applied. The second coat shall not be the same colour as either the 1st or 3rd. Both methods of protection shall totally enclose the substructure within a waterproof membrane to the limits shown on the Drawings.

(2) Internal and External Exposed Surfaces Where exposed surfaces of concrete structures are not protected by reinforced plastic liners one of the following systems will be indicated on the Drawings where required. a) An epoxy resin, acrylic, polyester or latex paint system: The surface shall first be wire brushed and all dust and loose scale

removed (refer to Clause 19.4 for schedule of surface preparations). An epoxy resin or other primer/sealer (for concrete and allied substrates) shall then be applied followed by coats of high build epoxy airless spray or other coatings to give a minimum dry film thickness (dft) of 300 microns. Freedom from pinholes shall be established by use of a spark tester. The approved paint system must have adequate flexibility to suit the thermal movements of the concrete without cracking whilst maintaining an effective bond.

b) A PVC sheet lining system : The PVC sheet lining shall be fixed such that the keys or ribs are cast

into the concrete surface. The lining shall be capable of taking up the same profile as the concrete substrate as indicated on the Drawings.

Site operatives for employment on this work shall be certified by the

manufacturer as trained to a satisfactory standard in fixing and welding techniques.

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After completion of either of the linings or systems as described in sub-clauses (a) and (b) above they shall be offered for inspection and testing. Two sets of testing equipment, e.g. feeler probes and spark testing, shall be provided and be maintained and available at all times for the sole use of the Engineer's Representatives. Only linings or systems completely free from pinholes will be accepted.

9.2.3 Reinforced Plastic Liners The construction methods employed shall be so as to ensure that a completely water and gastight seal is made preventing any exposure of the concrete surround to the corrosive liquids and gases present as detailed below and in Clauses 15.5.4 and 15.5.5. In particular:- Reinforced plastic liners shall be handled in the same manner as reinforced plastic pipes. In addition, extra care shall be taken to avoid damage to the liners which are not designed to carry loads. The manufacturer shall visit the site to demonstrate to the Contractor in the presence of the Engineer's Representative the methods of handling and lifting, including formation of the joints between the chamber liner. The Contractor is reminded that these liners are not designed to withstand pressure exerted by the concrete during construction.

9.2.4 Cutting and Sealing of Reinforced Liners Where the Contractor is required for any reason to cut reinforced plastic liners, he shall seal the exposed ends with an approved resin before incorporating the cut reinforced plastic in the work. No cut reinforced plastic shall be used until the resin has cured. The resin shall be as recommended by the manufacturer of the reinforced plastic item and shall be pigmented so that the areas where it has been applied are easily identifiable. It shall be delivered to site in sealed containers bearing the name of the manufacturer and properly labelled as to its content and shelf life.

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9.3 ODOR CONTROL FACILITIES

9.3.1 General The Contractor shall provide the labor, materials and equipment necessary to install and test the odor control facilities as shown on the Contract Drawings and as specified herein. The odor control units shall be either of the activated carbon filter types or of the natural soil filter bed types as indicated in the Drawings.

9.3.2 Soil Moisture and pH Probes Moisture and pH probes shall be able to continuously measure percent moisture and pH in the soil. All components shall be highly resistant to corrosion due to sewage and very high concentration of hydrogen sulfide and other gases. Soil moisture probes shall measure moisture on a percentage basis in the full range of soil moisture (0-100 percent). pH probes shall at a minimum be accurate within the 4-10 standard unit range. All probes shall be designed for maintenance and replacement with minimum soil disturbance.

9.3.3 Activated Carbon Odor Control Filter The activated carbon odor control filter shall be furnished and installed in accordance with Clause 17.2.48. The air blowers for the odor control unit shall be as specified in Clause 17.2.17.

9.3.4 Natural Soil Odor Control Filter

9.3.4.1 Materials

HDPE (High Density Polyethylene) Liner The HDPE liner shall be furnished and installed in accordance with Clauses 19.3.4 and 19.2.13 and as shown on the Contract Drawings. Washed Stone Stone for the air plenum shall be washed, rounded, uncrushed, well graded in size from 20 mm to 25 mm and consisting of clean, and durable particles free from dirt, vegetation or other objectionable matter and free from an excess of

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soft, thin elongated, laminated or disintegrated pieces. The Contractor shall submit a sample of the stone to the Engineer for approval prior to placement. Wood Chips Wood chips shall be obtainefrom hardwood and shall be of 10 mm to 50 mm diameter. Not more than 2 percent shall consist of leaves, twigs or shavings. They shall be free of extraneous materials, stone and debris. The Contractor shall submit a wood chip sample to the Engineer for approval prior to placement. Soil Filter The soil filter shall be a mixture of approved natural sand or sandy loam and treated compost. The compacted soil/compost mix shall have a 50 percent porosity. The compost shall be a product of thermophilic aerobic stabilization. It shall be adequately stabilized, so as to be completely free of any odors. The compost shall be friable, pass through a 13 mm mesh screen, and be free of stones, stocks and all objectionable debris. Compost shall have a pH of 5.5 to 8.0 and no less than 25 percent volatile solids. The compost source is subject to the review of the Engineer. All compost shall be "cured" to the point that it is no longer self heating.

9.3.4.2 Installation The Contractor shall place the stone, wood chips, soil and compost in layers of uniform thickness as indicated on the Contract Drawing(s) or as directed by the Engineer. The stone, wood ships, soil and compost shall be placed so as not to damage the aeration piping. Damaged piping is to be replaced by the Contractor at no additional cost to the owner.

9.3.4.3 Monitoring

The Contractor shall perform the following selected soil and atmospheric analyses at the direction of the Engineer, but not more than once per week with the exception of soil moisture and pH, for the length of the natural soil filter maintenance period. The results of the analyses shall be recorded and presented to the Engineer at the end of each month. Soil samples must be taken so as not to disrupt the even distribution of air through the odor control filter. Atmospheric Hydrogen Sulfide

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Hydrogen sulfide (H2S) gas concentrations shall be measured in the atmosphere directly over the filter bed with a probe placed immediately above the surface of the natural soil filter. The H2S levels shall be monitored and recorded continuously. Soil Moisture and pH Soil moisture and pH shall be monitored and recorded continuously at a depth of 0.75 meters from the natural soil filter surface using the soil moisture and pH probes as specified in Clause 9.3.2. Chlorides, Sulfides and Biological Analysis Chloride and sulfide concentration shall be measured from soil sample collected at a depth of approximately 0.75 meter from the natural soil filter surface. A biological analysis shall be performed on the same soil samples to identify biological organism in the filter media. The samples for these analyses shall be taken once per month unless otherwise directed by the Engineer.

9.3.4.4 Maintenance Where excessive settling or discontinuities have occurred in the soil filter media, the Contractor shall replace the entire soil/compost media or add additional soil/compost mixture at the direction of the Engineer.

9.3.4.5 Acceptance Test The Contractor shall test the porosity of the compacted soil/compost mixture before placement and provide the results of the test to the Engineer.

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10.1 CONCRETE 10.1.1 Tolerance

Floor and roof slabs shall be level to a point within ± 5 mm of the level shown on the drawings. Columns and beams shall have no irregularities exceeding 3 mm in a 3m length. The position of the face of columns, beams and walls at any point shall be within 5 mm of its position derived from the drawings.

10.1.2 Concrete Finish

All exposed concrete beams, columns and slab surface described as fair-faced shall be Type f.f. as follows:-

Type f.f. shall be an as struck finish entirely free from honeycombing, stains, pins, clippings, lining joint marks, nail and screw marks, raised grain marks, air holes and surface defects and shall be uniform in colour tone and surface texture with clean true faces and arises.

10.1.3 Construction Bays

The Contractor shall submit to the Engineer for his approval prior to concreting his proposals for the sequence of placing concrete and the position of horizontal and vertical construction joints.

10.1.4 Small Precast Items

Small precast items such as lintels, sills and padstones shall be built in as the work proceeds and have a fair-faced Type f.f. finish where exposed to view and hacked surfaces where plastered.

Lintels shall have a minimum bearing of 100 mm or larger if indicated on the drawings and shall have inserts for fixing windows and/or doors cast-in.

Sills shall be weathered and have a throat as described, if projecting, and shall have inserts for fixing windows and/or doors cast-in.

10.1.5 Cast-in Fixings

Cast-in fixings shall be securely fixed to formwork ready for casting and shall be

true to line in the positions shown on the drawings.

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10.1.6 Timber Cast-in Fixings

Timber cast-in fixings shall be made from 38 mm x 38 mm dovetailed shaped softwood battens pressure impregnated with preservative.

10.2 BRICKWORK AND BLOCKWORK

10.2.1 Damp-Proof Course

Horizontal and vertical damp-proof courses shall be hessian based lead cored bituminous damp-proof course weighing not less than 4.4 kg/m2 to accepted standards and approved by the Engineer.

Horizontal damp-proof courses shall be laid on an even level bed of fresh mortar

and shall be lapped for the full width of the sheet at corners and junctions. Stepped damp-proof courses shall be wide enough to be built in to both skins of the wall and to cross the cavity in one piece.

Vertical damp-proof courses shall be continuous and shall be the width of the

block closing the reveal. Damp-proof courses shall not be bridged with mortar.

10.2.2 Wall Ties Wall ties shall be 18/8 stainless steel vertical twist type 200 mm long.

Wall ties shall be built in the mortar beds as the work proceeds and shall be

spaced at a maximum of 900 mm horizontally and 450 mm vertically and shall be staggered. Each door and window opening shall have wall ties at each joint at 225 mm centres vertically.

10.2.3 Door and Window Frame Ties

As described for Joinery Fixing Accessories. Door and window frame ties shall be fixed as described under Joinery Work. 10.2.4 Mastic

Mastic for pointing door and window frames shall be one part gun-grade

polysulphide mastic to accepted standards and approved by the Engineer.

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Mastic seals to windows or door frames shall be neatly gun applied to clean, solid and dry backgrounds in one operation. The mastic shall be a triangular seal across the whole joint and any surplus shall be cleaned off when set.

10.2.5 Brickwork and Blockwork

Brickwork and blockwork shall be as specified in Section 5.

10.2.6 Cement Mortar Cement Mortar shall be as specified in Section 5.

10.2.7 Pointing

All pointing shall be done as the work proceeds and shall be flush with face of blockwork.

10.2.8 Hollow Walls

Hollow walls shall be constructed with an outer skin of blockwork and an inner

skin of blockwork leaving a cavity of the widths shown. The two walls shall be tied together with wall ties as described and the cavity shall be kept and left clear of all droppings. Openings shall be left at intervals in the blockwork at the bottom of the cavities and all debris shall be cleared out and the openings bricked up on completion. Cavities shall be closed at opening reveals with either brick or block to match the surrounding material and a continuous vertical damp-proof course shall be built in.

10.3 ROOFING

10.3.1 Roof Screed

Roof screed shall be laid to fall over the concrete roof slab and have a minimum

thickness of 35 mm and maximum thickness of 75 mm. The screed shall be thoroughly mixed 1:4 cement/sharp sand mix with very little water added. The screed shall be laid and compacted and shall be levelled off and finished with a steel trowel. Precautions must be taken to prevent rapid or excessive drying out.

10.3.2 Roof Primer

Primer for concrete shall be suitable for use with the waterproofing membrane

and shall be applied in accordance with the manufacturer's instructions.

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10.3.3 Waterproofing Membrane Flexible waterproofing membrane for roofing shall be bitumen based to accepted

standards and approved by the Engineer. Surfaces to receive the membrane shall be smooth, dry and free from dust. The

membrane shall be laid on a primed surface and in accordance with the manufacturer's recommendations.

10.3.4 Roof Insulation

Roof insulation shall be 75 mm thick closed cell non-absorbent rigid polystyrene

insulation board. The insulation boards shall be placed immediately after the membrane has been laid.

10.3.5 Roof Surface

Roof surface shall be 50 mm thick 450 mm x 450 mm precast concrete paving

slabs laid dry. 10.3.6 Roof Decking

The roof decking shall be aluminium profiled sandwich sheeting fixed to Metsec ‘Z’ section purlins all in accordance with the manufacturer’s instructions. The Contractor shall provide working drawings and manufacturer’s literature for approval before ordering the same.

10.3.7 Fascia Cladding The fascia cladding shall be of single skin construction formed from profiled

aluminium sheeting with matching aluminium profiled flashings. The Contractor shall provide working drawings and manufacturer’s literature for approval before ordering the same.

10.4 JOINERY

10.4.1 Timber-General

Timber for joinery shall be air dried and the moisture content be allowed to

reduce until it reaches a level in equilibrium with local conditions. It will be deemed to have reached equilibrium when the moisture content is 12% + 2%.

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10.4.2 Timber Sizes Timber shall be 3 mm less per wrought or finished face than the sawn size.

10.4.3 Hardwood

Hardwood for joinery shall be sound, well conditioned and seasoned Mahogany or Meranti with an average density of 529 Kg/m

3 and a moisture content of 12% +

2%. Exposed surfaces of joinery shall comply with the following requirements.

Knots : Pin knots up to 6 mm diameter will be permitted. Checks & Shakes : Checks up to 3 mm width and 300 mm long will be

permitted. Pitch Pockets : Not permitted unless cut out and filled. Plugs and Inserts : Not permitted. Joints and Lamination Glue Lines : Not permitted.

Rate of Growth : Not fewer that 8 growth rings per 25 mm at any point on any cross section.

Slope of Grain : Not greater than 1 in 8.

Species & Character : Same on all surfaces and matched as far as possible. Pinholes : Permitted if filled. A sample of each representative section for use in the work shall be previously submitted for approval by the Engineer's Representative.

10.4.4 Timber Fixing Accessories

Nails for fixing joinery shall be aluminium or sheradised mild steel. Screws for fixing joinery shall be sheradised mild steel. Bolts shall be stainless steel. Adhesives for exterior use shall be synthetic resin types, weather and boil-proof, complying with the approved standard. Adhesives for interior use shall be synthetic resin types, moisture resistant and moderately weather resistant, complying with the approved standard.

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Door frame and lining fixing cramps shall be of 25 mm wide x 14 swg thick x 250 mm girth stainless steel, one end turned up 50 mm and twice drilled and the end fishtailed for building-in.

Dowels for fixing door frames shall be 10 mm dia. x 100 mm long stainless steel.

10.4.5 Timber Preservative

Timber preservative shall be water repellent and protect the timber from all wood destroying fungi and insects particularly termites. The preservative shall be applied in accordance with the manufacturer's instructions including treatment to all ends, notches and joints in treated timber out on site.

10.4.6 Ironmongery

Ironmongery shall be as shown on the drawings.

10.4.7 Workmanship

All exposed faces of joiners work shall have wrought faces.

All arises shall be rounded to a 1.5 mm minimum radius unless specified or drawn to a greater radius.

Where the term 'framing or framed' is used it shall mean all halvings, dovetails,

tenons and hardwood pins and the best known means of putting this work together.

10.4.8 Storage

All joinery shall be protected from the weather during transit and shall be stored

under cover, clear of the ground in clean, dry ventilated conditions so as to maintain the specified moisture content.

All framework shall be put together loosely and stored as described and shall not

be wedged and glued together until required for fixing. 10.4.9 Door Frames

External door frames shall be built-in as work proceeds with fixing cramps as

described. The fixing cramps shall be screwed to the back of the frames at 450 mm maximum centres with two sheradised screws 25 mm long. The fishtail ends

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shall be built-in to the brickwork or blockwork mortar joints as the work proceeds.

10.4.10 Doors

External doors shall be hung on one and a half pairs of hinges unless otherwise

detailed, to give a maximum tolerance all round of 2 mm.

10.5 METALWORK

10.5.1 Aluminium Aluminium alloy sections for aluminium shall be type H59 TF box sections.

10.5.2 Aluminium Louvers

Aluminium louvers shall be made from NS 4 H3 aluminium and have a natural or

bronze anodised finish. Sizes to be as shown on the drawings. 10.5.3 Aluminium Windows

Aluminium windows shall be manufactured by an approved specialist window

manufacturer from extruded aluminium sections mechanically cleated and sealed. Glazing to be fixed into opening with clip on aluminium beads and gasket sealed.

Finish to windows to be natural anodised 25 microns in thickness. Windows are

to be fixed into openings with stainless steel screws and sealed all round in mastic bedding.

10.5.4 Ironmongery

Rates for supplying and fixing ironmongery shall include for all boring, cutting,

mortising, sinking, making good, replacing damaged screws, oiling, adjusting, leaving in good working order and mastering all locks.

Screws shall be of suitable gauge and material for the purpose and shall match the

item to be fixed. 10.6 PLUMBING

10.6.1 Copper Tubes

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Copper tubes shall be half hard copper tube of accepted standard approved by the Engineer.

10.6.2 Copper Fittings, Waste Pipes, Ball Valves etc.

All fittings shall be of an accepted standard approved by the Engineer and as

described on the drawings.

10.6.3 uPVC Pressure Pipes and Fittings

uPVC pressure pipes and fittings for water supply shall be of an accepted standard approved by the Engineer.

10.6.4 Workmanship

The plumbing installation shall be carried out to the satisfaction and in

accordance with the Acts and By-laws of the Dubai Electricity and Water Authority.

10.6.5 Pipework

All pipework shall be neatly executed in long lengths to avoid unnecessary

jointing. Horizontal pipes shall be fixed with a slight fall to prevent airlocks and to enable the system to be easily drained down.

10.6.6 Copper Tube Fixing

Copper tube shall be fixed clear of walls and ceilings with two piece copper

spacing clips or with proprietary plastic pipe clips. Clips shall be at 1.20m horizontally and 1.50m vertically for 15mm diameter pipes and at 1.80m and 2.40m respectively for 22mm and 28mm diameter pipes. Capillary joints shall be neatly made with all surplus solder removed.

Screw threads on compression joints shall be wrapped with PTFE tape prior to

tightening.

10.6.7 Waste Pipes uPVC waste pipes for sinks and urinals shall be fixed and jointed in accordance

with the manufacturer's instructions. Fixing clips shall be at 0.50m horizontally and 1.20 m vertically and joints shall be by 'O' rings, seals or solvent cement. Care shall be taken to allow for expansion in accordance with manufacturer's instructions.

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10.6.8 Sleeves

uPVC sleeves shall be provided through walls and ceilings for pipes and shall be

internally 3 mm minimum larger than the pipes.

10.6.9 Testing Soil and waste pipes shall be air tested for leaks to a pressure of 38 mm water

gauge, constant for three minutes. Rainwater pipes shall be tested for leaks as above and gutters shall be tested by

filling with water to overflow level. Testing shall be undertaken to hidden sections of pipework before they are

built-in. All leaks found shall be rectified and retested. 10.6.10 Storage Tanks GRP cold water storage tanks shall be placed on 2 nos. galvanised mild steel

brackets bolted to the wall. 10.7 PLASTERWORK & OTHER WALL, FLOOR & CEILING FINISHES 10.7.1 Cement Cement shall be Portland Cement as described in Section 3. 10.7.2 Lime Lime shall be the hydrated type to the approved standard. 10.7.3 Sand Sand for plasterwork with gypsum plasters shall be suitable for use with the brand

of gypsum plaster used. Sand for rendering, internally and externally, and floor screeds shall comply with Clause 5.1.3.

10.7.4 Gypsum Plasters Gypsum plaster shall be of an accepted standard approved by the Engineer.

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10.7.5 Plaster Trims Metal angle beads and plaster stops for plasterwork and plasterboard shall be

manufactured from galvanised mild steel. 10.7.6 Metal Lathing Metal lathing shall be manufactured from galvanised mild steel having a

minimum shortway aperture of 6 mm. 10.7.7 Plasticizers Plasticizers shall be an approved vinyl resin type and used in the manner and

proportions recommended by the manufacturer. 10.7.8 Bonding Agents Bonding agents generally shall be an approved polyvinyl acetate (PVA) type and

used in the manner and proportions recommended by the manufacturer. 10.7.9 Storage Plaster shall be stored in a building in dry condition on timber platforms and shall

be used within two months of manufacture. Plasterboards shall be stored in a building in dry condition and shall be laid flat

and stacked on a sheet of polythene. 10.7.10 Floor Tiles Vitrified and fully vitrified floor tiles shall be as detailed on the drawings. Floor tiling shall be laid with a proprietary tile adhesive (approved by the

Engineer) either directly onto a clean, dry and level concrete sub-floor, or on a cement/sand screed laid over the sub-floor. The sub-floor surface shall be scabbled to remove all surface laitance prior to tiling or screeding. The screed shall be mixed semi-dry by hand or in a pan mixer and shall be a 1:4 cement/sharp sand mix with just enough water to enable it to hold together when squeezed in the hand. The sub-floor shall be kept damp for 24 hours and the screed shall be laid and well compacted to a thickness of 56mm and brought to the required levels using a draw float. The finished floor screed shall be kept damp for a period of 7 days prior to commencement of tiling. The tile adhesive shall be spread evenly by steel trowel to a thickness of 3mm onto which the clean,

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dry tiles shall be laid to give a 3mm minimum joint width. The tiles shall be grouted with a proprietary and approved tile grout within a minimum period of 24 hours after laying.

10.7.11 Wall Tiles (Internal) Coloured wall tiles shall be 152 x 152 x 5.5mm thick glazed tiles approved by the

Engineer. 10.7.12 Wall Tiles (External) External wall tiles shall be as detailed on the drawings. The concrete surface to receive tiling shall be prepared as follows :-

1) Concrete surface to be 100% keyed by either bush hammering, hacking or water scabbling of smooth surface.

2) Concrete surface shall be thoroughly moistened and a concrete slurry mix

of one part cement to two parts of medium sharp sand applied as splatterdash thrown onto concrete surface.

3) While the surface is wet apply 1:3.5 mix sand/cement render to a thickness

of 12mm in two coats to a plumb and level finish and with wood float finish.

The completed rendering is to be protected and allowed to dry slowly with

damping as necessary. After curing, the surface is to be allowed to dry completely before the fixing of tiles.

Tiles shall be fixed with proprietary tile adhesive (approved by the Engineer). The

tiles are to be bedded strictly in accordance with the manufacturer's instructions with 10mm joints between tiles.

At least 24 hours after fixing tiles are to be jointed using approved mortar. Movement joints are to be formed between tiles in positions shown on the

drawings to the full depth of the tiles, bedding and render. Joints are to be 10mm wide and are to be filled to within 8mm of surface with inert filler and finished with 2 part polysulphide pointing in colour to match tile jointing.

10.7.13 Tile Adhesive

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Tile adhesive for floor and wall tiling shall be as recommended by the Tile

Manufacturer and used in accordance with the adhesive manufacturer's instructions.

10.7.14 Tile Grout Tile grout for floor or wall tiles shall be as recommended by the manufacturers of

the ceramic tiles and used in accordance with the manufacturer's instructions. 10.7.15 Expansion Joints Expansion joints in floor and wall tiling shall be 6.5 mm wide Polyethylene

backing strip with 6.5 mm wide approved silicone sealant, gun applied on the face in accordance with the manufacturer's instructions.

Expansion joints in floor tiling shall be at 6 m maximum centres in both

directions and around the perimeter of rooms, over structural joints and around machine bases and holes in the floor. The joints shall be the full depth of the floor tiles, bedding and screed x 6.5 mm minimum width. The joints shall be primed with two coats of approved primer and when dry, filled up to within 6 mm of the tile finish with polyethylene compressible foam strip. An approved joint sealant shall then be gun applied and tooled to a slightly concave smooth even finish.

10.7.16 Backgrounds All backgrounds shall be clean, dry, free from efflorescence, paint, oil and dust

and adequately prepared to provide a good key. All loose, flaking and unsound material shall be completely removed and all mortar joints shall be raked out, if required, to a minimum depth of 10 mm. Concrete surfaces shall be well wetted five minutes prior to plastering or rendering.

10.7.17 Dissimilar Materials Joints between dissimilar materials such as blockwork and concrete shall be

covered with a 300 mm wide continuous strip of expanded metal lathing fixed to both sides with masonry nails or plugs and screws at 200 mm centres.

10.7.18 Hacking Concrete surfaces shall be well hacked to expose the aggregate thus providing a

firm coarse textured background.

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10.7.19 Dubbing Out Dubbing out of all areas to receive plaster or render shall be in the same mix as

the subsequent coat, not exceeding 10 mm thickness in one application, and shall be allowed to harden.

10.7.20 Splatterdash or Stipple Coat Splatterdash or stipple coats shall consist of 1:1.5 cement/sharp sand mixed with

50% water/50% PVA bonding agent to form a thick slurry. The mixture shall be vigorously brushed onto the background and stippled to give a close textured key. The resulting finish shall be kept damp to prevent rapid drying out and allowed to harden for seven days minimum before subsequent coats are applied.

10.7.21 Internal Finishes-General All internal finishes shall not commence until the building is watertight, including

glazing, and reasonably dried out. 10.7.22 Internal Render Internal render shall be applied to concrete blocks as follows :- The render shall be two coat work comprising a stipple coat as described

previously and a finishing coat giving a maximum thickness of 12 mm. The mix shall be in the proportion 1:1:6 cement/lime/sand. The render shall be kept damp for a minimum of three days. All window and door openings must be closed to prevent through draughts causing rapid drying out.

10.7.23 Stucco A PVA copolymer based putty for concrete and plaster shall be applied, in

accordance with the manufacturer's instructions, to the surface of the internal render after curing has taken place. The stucco shall only be applied in sufficient thickness to seal the surface of the render and remove minor surface irregularities to give a smooth surface ready to receive the decorative finish.

10.7.24 External Render External render shall be applied to concrete, concrete blocks and clay bricks as

follows :-

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The render shall be three coat work comprising a stipple coat as described previously, an undercoat and a finish coat giving a maximum thickness of 16 mm. The mixes shall be in the proportions shown on the schedule of mixes. The undercoat shall be level, true and of sufficient thickness to prevent the background joints showing through and shall be kept damp for three days before applying the final coat.

Where shown on the drawings the final coat shall be approximately 5 mm thick

coloured Tyrolean open honeycombed texture machine applied render. A key for the final coat shall be provided by combing the undercoat prior to

setting with wavy lines 20 mm apart and 5 mm deep. The final coat shall be 6 mm minimum thickness and worked to a level and smooth finish with a wooden float with clean, true and level arises. The whole shall be protected from rapid drying out in hot, dry and windy weather.

Table 10-1. Schedule of Mixes for External Render

Mix Type

Concrete,Concrete Blocks or Engineering Bricks

Aerated Concrete Blocks of Soft Clay Bricks

Undercoat Finish Undercoat Finish

Cement:Lime:Sand 1:1.5:4 1:1:5 1:2:8 1:2:8 to 4.5 to 6 to 9 to 9 Cement:Ready-Mixed Lime / Sand

1:4 to 4.5

1:5 to 6

1:8 to 9

1:8 to 9

Cement:Sand with Plasticizers

1:3 to 4

1:5 to 6

1:7 to 8

1:7 to 8

10.8 GLAZING 10.8.1 Glass Glass for glazing shall be the best of its respective kind and free from blemishes

and imperfections. Glass shall be as shown on the drawings. 10.8.2 Bedding Compound The bedding compound for external glazing shall be an approved non-setting

butyl rubber based proprietary compound and sufficiently elastic to allow for thermal or other movement of the glass and timber, compatible with the approved decorative wood stain.

The bedding compound shall show no sign of separation after bedding.

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10.9 PAINTING AND DECORATING 10.9.1 Painting-General All primers, oil bound undercoats and finishes, emulsions and polyurethane

interior varnishes shall be used in strict accordance with the manufacturer's recommendations and shall be obtained from an approved manufacturer.

Only fresh paint delivered to site in original sealed containers shall be used. Each

container shall be labelled with the manufacturer's name, contents, colour, quantity, batch number and date and instruction on method of application.

10.9.2 Exterior Stain Pigmented stain shall be PX 65 as manufactured by Sadolin's Ltd., and used in

accordance with their recommendations, or other equal and approved, two coats before fixing and one coat after fixing.

10.9.3 Workmanship All painting shall be carefully executed with clean brushes and in the best manner

and applied strictly in accordance with the manufacturer's instructions. All paints, stains and varnishes shall be well stirred before use and thinned only in

accordance with the manufacturer's recommendations. Painting of exterior work shall not be carried out in wet, dusty or foggy weather

and interior work shall not proceed in dusty conditions. All woodwork shall be prepared to a fine clean finish by scraping or sanding all

made dust free immediately before painting and coating. 10.9.4 Stopping to Plaster Plaster shall be clean and dry and free from loose material. Holes and cracks shall

be cut back and solidly filled, allowed to dry and rubbed down smooth. 10.9.5 Steel Priming

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Mild steel shall be blast cleaned and primed with two coats of primer within four

hours of cleaning. Galvanised mild steel shall be degreased with white spirit and primed with two

coats of primer. 10.9.6 Oil-Based Paint Interior primed softwood and all primed mild steel shall be painted with two

undercoats and one gloss or semi-matt finish coat of oil-based paint to give a smooth, even and solid finish, all as instructed. Each coat shall dry overnight before applying further coats.

10.9.7 Internal Finish to Walls The paint finish to internal walls shall be PVA copolymer matt emulsion paint or

as detailed on the drawings. 10.9.8 Ironmongery All fixed ironmongery except hinges shall be removed before painting and refixed

on completion.

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12.1 GENERAL

The Contractor shall be responsible for the safety of personnel and the public during the contract period and compliance with safety requirements stated herein shall not relieve the Contractor of his responsibility or liability under the Contract. Prior to the commencement of the Works, the Contractor shall submit a safety policy for the Contract detailing all proposed specific safety arrangements for the agreement of the Engineer. This shall include but not be limited to the requirements set out in this section. If at any time safety requirements are not being met by the Contractor, the Engineer shall have the right to instruct the Contractor on the necessary safety provisions and the Contractor shall comply with such instructions forthwith. The Contractor shall notify the Engineer immediately of any accident that occurs whether on or off site in which the Contractor is directly involved which results in any injury to any person whether directly concerned with the site or whether a third party. Such initial notification may be verbal and shall be followed by a written comprehensive report within 24 hours of the accident.

12.2 FAMILIARISATION WITH SAFETY PROBLEMS

The Contractor shall make himself familiar with the condition of the site before tendering in order to assess the nature of safety problems he is likely to encounter and the safety requirements.

12.3 SAFETY OFFICER The Contractor shall appoint a Safety Officer who shall be responsible for all aspects

of safety. He shall be conversant with and experienced in all general civil engineering construction and sewer safety techniques and emergency procedures, and shall be on site at all times operatives are working. He shall enforce and supervise the safety procedures at all places of works and make sure that adequate safety equipment, required under Clause 12.5, is available in good working condition and at all places of works at the time works are on-going.

The Safety Officer shall also be responsible for organizing, implementing and

maintaining any road closures, traffic diversions, removal of parked cars causing an obstruction, etc., in adequate time to ensure compliance with the Contract programme.

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12.4 SAFE WORKING CONDITIONS AT THE SITE

The Contractor shall provide Method Statements detailing proposed safe methods of work with the Tender. The methods should generally follow the recommendations of the following publications: 1) Code of Construction Safety Practice as published by the Dubai Municipality.

2) Administrative Order No. 330 in connection with Safety Manual of Dubai

Municipality. 3) Health and Safety Guideline No. 2, Safe Working in Sewers and at Sewage

Works as published in the United Kingdom. Accident procedures and emergency procedures shall be fully detailed.

No persons shall be allowed to enter a confined space until the safe methods of work have been agreed upon and fully implemented to the satisfaction of the Engineer.

12.5 SAFETY EQUIPMENT

The Contractor shall make sure, prior to commencement of works on site, that adequate safety equipment, apparatus and devices are available, and that as a minimum the following equipment and devices are available at each entry point to a confined space:- Type of Equipment No. Required

a. Safety harness and ropes 2 b. Lifting frame and tackle for safety harness 1 c. Gas detector (suitable for H2S) 2 d. Approved mechanical air blower and power supply 1 e. Emergency breathing apparatus 2 f. Atmosphere monitoring device, capable

of monitoring oxygen levels, and levels of toxic and flammable gas 1

g. Washing facilities with disinfectants, toiletries As Required h. Communication facilities As Required i. Lighting (explosion proof) As Required

All personnel working on, visiting or inspecting any part of the Works shall be

provided with and be required to wear appropriate protective clothing or apparatus. This may include:-

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Safety helmets, coats, gloves, footwear, goggles, ear muffs, breathing apparatus and

any other protective apparel or any other equipment deemed necessary by the Engineer.

Every hoist, lift, sling, chain, rope, pulley block and any other lifting tackle, used in

the Works shall be thoroughly examined by a competent person at least once every 6 months and shall be test loaded to 150% of the safe working load and shall then be tagged with the safe working load and the date of successful testing by an authorised testing authority.

All parts and working gear whether fixed or movable, including the anchoring and

fixing appliances of every crane and lifting machine shall be of good construction, sound material, adequate strength and shall be properly maintained. All parts and gear shall be examined at least once every twelve months.

A register of all such equipment and examinations shall be kept up to date by the

Contractor and be available for inspection by the Engineer. 12.6 SAFETY PROCEDURES 12.6.1 General

All excavation shall be adequately supported against collapse and provided with protective safety barriers and appropriate warning signs and bunting. Suitable and sufficient scaffolds shall be provided and properly maintained for all work that cannot safely be carried out from the ground or from part of the structure or from a ladder. Every scaffold shall be of good construction, of suitable and sound material and of adequate strength for the purpose for which it is used. Unless designed as an independent structure, every scaffold shall be rigidly connected to a part of the structure which is of sufficent strength to afford safe support. Protective headgear shall always be worn. All manufacturer’s instructions and recommendations for the use, application, erection or construction of any material or item of equipment or plant shall be followed precisely. Special care shall be taken to protect all employees when using power tools or materials which will produce a fine dust and in particular all asbestos based products. The operator should stand upwind of the operation and wear an approved respirator and goggles. Wherever possible overalls should be worn and should consist of 60% polyester fibre and 40% cotton. Transportation of any material by the Contractor shall be in suitable vehicles which when loaded do not cause spillage and all loads shall be suitably secured. The

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Engineer shall have the right to instruct the withdrawal from the site of any vehicle which does not comply with these requirements or any of the Dubai or UAE traffic regulations and laws. The Contractor shall adopt the safety procedures as proposed by him as per Clause 12.4 for entry into a manhole or other confined space. However, the following safety procedures are outlined as a guide only. The Contractor shall, where appropriate, use these procedures in addition to his proposed procedures while entering into a manhole or a confined space. Also included are additional information on safety procedures for manhole entry in Appendix 3 contained in Part 3 of 3 of these Specifications for his guidance and use where appropriate. It shall be explicitly understood that safety is the responsibility of the Contractor and use of any of these procedures as outlined under this clause or in Appendix 3 shall not relieve him of any of his contractual responsibilities. a) The manhole or confined space shall be thoroughly vented by mechanical air

blower prior to entry. b) A full gas check is to be undertaken prior to entry. If the level of toxic or

explosive gases is above the safe level (maximum acceptable for hydrogen sulphide is 10 ppm) or the level of oxygen is below a safe level (18%) then entry is not permitted without the use of full breathing apparatus.

c) All persons entering a manhole or a confined space shall wear a safety harness

properly rigged to the lifting frame. d) The mechanical air blower shall be kept close by the manhole or confined space

which has been entered. e) The hydrogen sulphide level in the manhole or confined space shall be

continuously monitored. If the level rises above 10 ppm then the manhole or confined space shall be evacuated immediately.

f) At least two people shall be available close to the point of entry to operate the

air blower and lifting tackle in the event of an emergency and who shall note the location of the nearest telephone in working order and the telephone number of the nearest hospital before entry is permitted.

g) No smoking shall be permitted and ‘no spark’ tools shall be used.

12.6.2 Atmosphere Monitoring

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When any person is in a confined space, the atmosphere at the work place and at the base of the access manhole or pit shall be continuously monitored by a Monitoring Device to detect oxygen deficiency, flammable gas and toxic gases. The monitoring equipment shall be designed to be lowered into the work place or access manhole and shall not depend on a sample draw tube from the surface. The monitoring equipment shall be the first piece of equipment to be lowered into the place of work and shall be the last piece of equipment removed. The Contractor shall provide, maintain and calibrate the approved monitoring equipment in accordance with the manufacturer's instructions. The Contractor shall provide adequate numbers of monitoring devices to fully cover all proposed work places and open manholes or access pits with adequate spare devices, parts and batteries as needed to ensure complete monitoring of all sites of work at all times throughout the construction period. No entry into a confined space shall be allowed until the monitoring devices have been properly placed at the work place or access site and the readings indicate that the atmosphere is safe. Operatives are to be fully trained in the use of the monitoring equipment and in the necessary response to alarm conditions.

12.6.3 Atmosphere Ventilation

Before any person is allowed to enter a confined space, the atmosphere shall be adequately ventilated. As a minimum, both ends of the sewer section or work place shall be opened to the atmosphere either by removing the manhole covers or through open access pits. Positive ventilation shall be provided at all times when a person is in a confined space, even if the atmosphere monitoring equipment indicates that the atmosphere is safe for access.

12.6.4 Safety Harness

Each person entering a confined space shall wear a harness at all times. The harness shall be designed such that it will enable an unconscious person to be lifted to the surface in a vertical posture.

12.6.5 Emergency Breathing Apparatus

Each person in a confined space shall have emergency breathing apparatus available and ready for use within the confined space. The breathing apparatus shall have a minimum capacity of 2 litres and a working pressure of 200 bar and shall be tested daily, prior to starting work.

12.6.6 Active Confined Space Entry

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Before any person is allowed to enter a confined space that is in active service, the Contractor shall ascertain the schedule of sewage flows which can be anticipated over the duration of the work. This shall include average and peak gravity sewage flows and the discharge flows from all upstream pumping stations. Should the combined gravity and pumped flows exceed safe working conditions at the work place, then the Contractor shall prepare a plan for the control and diversion of flows around or away from the work place. The method of flow diversion shall be as approved by the Engineer and by the Dubai Municipality. A "permit to work" system shall be employed for work on sewers where incoming flows (from pumping or diversion) are controlled by people remote from the work site.

12.6.7 Washing Facilities

Every work place where persons are entering a confined space, shall be provided with facilities for washing.

12.6.8 Communication The Contractor shall provide a means of communication, appropriate to the safe

system of work, between ground level and any work place within the confined space.

12.6.9 Lighting

When permanent works are being constructed or inspected, the confined space shall be adequately lit. The lighting apparatus shall operate at a voltage not exceeding 50 Volts. The circuit shall be protected against overload. No transformers, switches, fuses, contact breakers, etc., shall be taken into the confined space. Bulbs shall be protected against damage.

12.7 TRAFFIC CONTROL

Prior to initiating any work at a site, the Contractor shall prepare, for the approval of the Engineer, a plan for the diversion and control of traffic around the work site. The approved traffic control plan shall be submitted to the Dubai Municipality Roads Department and Dubai Traffic Police for review. Work at the Site may not commence until the traffic control plan has been approved by the Dubai Municipality Roads Department and Dubai Traffic Police. The traffic control plan shall include a street plan of the work site showing all traffic lanes and building access drives that will be affected by the work. The proposed system of traffic diversions and the manner of control shall be clearly illustrated, including the location and types of traffic cones, warning signs and warning lights to be used. The plan should indicate the anticipated schedule of works for which traffic

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must be diverted. Road diversions and road signs shall conform to Clause 1.3.4 and to Appendix 1 contained in Part 3 of 3 of the Specifications. The traffic control plan shall take into consideration the requirements of the work crew for access to the work site, for positioning and parking of vehicles needed for the work and for the temporary storage of equipment and materials.