Royal Government of Bhutan Ministry of Works and Human Settlement Department of Roads Construction, Operation & Maintenance of Dalbari – Dagapela Secondary National Highway (0.000 - 80.580 km) Volume II PARTICULAR TECHNICAL SPECIFICATIONS FOR BRIDGE WORKS Section A: Dalbari-Odalthang
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Royal Government of Bhutan
Ministry of Works and Human Settlement
Department of Roads
Construction, Operation & Maintenance of Dalbari –
Dagapela Secondary National Highway (0.000 - 80.580
km)
Volume II
PARTICULAR TECHNICAL SPECIFICATIONS FOR BRIDGE
WORKS
Section A: Dalbari-Odalthang
Page 1 of 69
Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
ABBREVIATIONS
AASHTO American Association of State Highway and Transportation Officials AC Asphalt Concrete ACV Aggregate Crushing Value AIV Aggregate Impact Value ALD Average Least Dimension ASTM American Society of Testing and Materials BOQ Bill of Quantities BS British Standards BSCP British Standards Code of Practice BSR Bhutan Schedule of Rates CBR California Bearing Ratio c/c center to center CR Crushing Ratio Cu.m Cubic metre DCP Dynamic Cone Penetrometer DoFS Department of Forestry Services DOR Department of Roads DGM Department of Geology and Mines dia Diameter ECOP Environment Code of Practice for Highways and Roads EMP Environmental Management Plan FI Flakiness Index GCC General Conditions of Contract HMAC Hot mix asphalt concrete HWL High Water Level IRC Indian Road Congress (i.e. Recommended Code of Practice by IRC) IS Indian Standards ISO International Organization for Standardization LAA Los Angeles Abrasion Value LWL Low Water Level MC Moisture Content MDD Maximum Dry Density min Minute MSL Mean Sea Level NEC National Environment Commission no Number (units), as in 6 no. No Number (order) as in No 6 OMC Optimum Moisture Content OPC Ordinary Portland Cement PCC Particular Conditions of Contract PI Plasticity Index PL Plastic Limit PM Plasticity Modulus (PI x % passing 0.425 mm sieve) PVC Polyvinyle Chloride QA Quality Assurance PS Provisional Sum QC Quality Control
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
RGoB Royal Government of Bhutan
RROW Road Right of Way
SE Sand Equivalent
sec Second
SG Specific Gravity
SI International Standard Units of Measurements
SSS Sodium Sulphate Soundness test, loss on 5 cycles
STV Standard Tar Viscosity
Sq.m Square metre
TS Tensile Strength
UC Uniformity Coefficient
UCS Unconfined Compressive Strength
VIM Voids in Mix
w/c Water cement ratio
Wt Weight
% Percent
Page 3 of 69
Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
Table of Contents
1.0 SECTION 1: GENERAL AND SITE ESTABLISHMENTS 9
1.1 General 9
1.1.1 Scope of Work 9
1.1.2 Site Acquaintance 9
1.1.3 Specifications 9
1.1.4 Reference to Bureau of Indian Standards Codes & Other Codes 9
1.1.5 Dimensions & Levels 9
1.1.6 Notice of operation 9
1.1.7 Work program 9
1.1.8 Time Schedule 9
1.1.9 Drawings 10
1.1.10 Sub-Contracting 10
1.1.11 Compliance 10
1.1.12 Supply of Materials 10
1.1.13 Ordering Materials 10
1.1.14 Material Quality 10
1.1.15 Equipment & Facilities 11
1.1.16 Work Site Register (Site Order Book) 11
1.1.17 Area for the Contractor 11
1.1.18 Unit of measurement 11
1.2 Site Installations 11
1.2.1 Establishment of temporary infrastructure and facilities 11
1.2.2 Contractor’s site office 12
1.2.3 Labor Camps 12
1.2.4 Waste Management 12
1.2.5 Material Storage 12
1.2.6 Temporary Drainage System 12
1.2.7 Site Water Supply and Electricity 13
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
1.2.8 Additional facilities to be provided 13
1.2.9 Survey Equipment 13
1.2.10 Sign Boards 13
1.2.11 Testing of Materials 14
1.3 General Contractor’s Obligations 16
1.3.1 Insurance 16
1.3.2 Safety measures and penalties 16
1.3.3 Protection of the Environment 16
1.3.4 Provision and Maintenance of labour Camps, waste management, material storage, temporary drainage system, water supply, electricity and communication facilities 17
1.3.5 As-Built Drawings 17
1.3.6 Maintenance and demobilization 17
1.4 Measurement and Payment 17
2.0 SECTION 2: EARTH WORKS 17
2.1 General 17
2.2 The Definition and Classification of materials for purpose of excavation shall be as follows: 18
2.2.1 Ordinary Soil (Normal Excavation) 18
2.2.2 Hard Soil (Intermediate Excavation) 18
2.2.3 Ordinary Rock (Intermediate Excavation) 18
2.2.4 Hard Rock (Hard Excavation) 18
2.2.5 Hard Rock ( Hard Excavation where blasting prohibited) 18
2.2.6 Marshy Soil 19
2.2.7 All Kinds of Soil 19
2.2.8 Authority for classification 19
2.3 Excavation 20
2.3.1 Setting out 20
2.3.2 Stripping and storing topsoil 20
2.3.3 Methods, tools and equipment 21
2.3.4 Rocks excavation 21
2.3.5 Marsh excavation 21
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
2.3.6 Blasting 21
2.3.7 Cutting 22
2.3.8 Disposal of Excavated Material 22
2.3.9 Pumping and Bailing 22
2.3.10 Foundation Fill Material 23
2.3.11 Backfill Material 23
2.3.12 Backfilling 23
2.4 Measurements and Payments 24
3.0 SECTION 3: STRUCTURRES 25
3.1 Concrete for structures 25
3.1.1 Standards 25
3.2 Description 25
3.3 Materials 25
3.3.1 Specifications for Materials 25
3.3.2 Testing of Materials 28
3.3.3 Composition of Concrete 29
3.3.4 Control of Concrete Quality 32
3.4 Construction Methods 34
3.4.1 General 34
3.4.2 Care and Storage of Concrete Materials 34
3.4.3 Preparations before Casting 35
3.4.4 Measuring Materials 35
3.4.5 Mixing Concrete 35
3.4.6 Handling and Placing Concrete 38
3.4.7 Perforations and Embedment of Special Devices 41
3.4.8 Finishing Concrete Surfaces 41
3.4.9 Construction Joints 42
3.4.10 Curing Concrete 43
3.4.11 Removal of Scaffolding and Formwork 43
3.4.12 Repair of Concrete 43
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
3.4.13 Depositing Concrete under Water 44
3.4.14 Factory Made Precast Concrete Elements 44
3.4.15 Control of Heat in Structures 45
3.4.16 Loading 45
3.4.17 Backfill to Structures 45
3.4.18 Cleaning Up 45
3.5 Measurement and Payment 45
3.6 Formwork and Scaffolding 46
3.6.1 Scaffolding (Falsework) 46
3.6.2 Formwork 47
3.6.3 Surface Treatment for Shuttering 48
3.6.4 Camber 48
3.6.5 Approval of Scaffolding and Formwork 48
3.6.6 Special Formwork 49
3.6.7 Removal of Form Work 49
3.7 Measurements and Payment 50
3.8 Reinforcement 50
3.8.1 Description 50
3.8.2 Materials 50
3.9 Construction Methods 51
3.10 Measurement and Payments 52
4.0 SECTION 4: MISCELLANEOUS 53
4.1 Drainage for Structures 53
4.1.1 Description 53
4.1.2 Drainage Spouts 53
4.2 Measurements and Payments 54
4.3 Open surface drains 54
4.3.1 General requirements 54
4.3.2 Scope 54
4.3.3 Excavation 54
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
4.4 Measurement and Payment 54
4.5 HDPE drainage pipes 55
4.5.1 Scope 55
4.5.2 Material 55
4.5.3 Placement 55
4.6 Measurement and Payment 55
4.7 Gabion protection works 55
4.7.1 Scope 55
4.7.2 Materials 55
Construction of Gabions 57
4.8 Measurement and Payment 60
4.9 Elastomeric Bridge Bearings 60
4.9.1 Scope 60
4.9.2 Steel reinforced Elastomeric Bearings 60
4.9.3 Properties of Elastomer 61
4.9.4 Steel Laminates 61
4.9.5 Bond 61
4.9.6 Manufacture 61
4.9.7 Fabrication Tolerances 61
4.9.8 Marking and Certifying 62
4.9.9 Testing 62
4.9.10 Installation 63
4.10 Measurement and Payment 63
4.11 Movement or Expansion Joints 63
4.11.1 Scope of Work 63
4.11.2 Specification for Strip Seal Expansion Joint 64
4.12 Measurement and Payment 67
5.0 SECTION 5: DAY WORKS 67
5.1 General 67
5.2 Dayworks Labour 67
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
5.3 Dayworks Materials 68
5.4 Dayworks Plant 68
LIST OF TABLES
Table 2.3-1 Grading of foundation fill material .................................................................. 23
inserts, fittings and other incidental parts necessary to provide for further supports of drain pipes in
accordance with the lines, levels, grades, sizes, dimensions and types shown on the Drawings.
4.1.2 Drainage Spouts
4.1.2.1 Scope
This work shall consist of furnishing and fixing in position of drainage spouts and drainage pipes for
bridge decks as per drawing and specification.
4.1.2.2 Fabrication
The drainage assembly shall be fabricated to the dimensions shown on the drawings; all materials
shall be corrosion resistant; steel components shall be of mild steel conforming to IS: 226. The
drainage assembly shall be seam welded for water tightness and then hot-dip galvanized.
4.1.2.3 Placement
The galvanized assembly shall be given two coats of bituminous painting before placement. The
whole assembly shall be placed in true position, lines and levels as shown in the drawing with
necessary cut-out in the shuttering for deck slab and held in place firmly. Where the reinforcements of
the deck are required to be cut, equivalent reinforcements shall be placed at the corners of the
assembly.
4.1.2.4 Finishing
After setting of the deck slab concrete, the shrinkage cracks around the assembly shall be totally
sealed with bituminous sealant as per IS:1834 and the excess sealant trimmed to receive the wearing
coat. After the wearing coat is completed, similar sealant shall be finished to cover at least 50 mm on
the wearing coat surface all round the drainage assembly.
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
4.2 Measurements and Payments
The measurement for payment for Drainage spouts shall be number/piece.
The contract unit rate for each drainage spout shall include the cost of all labor, materials tools and
plant required for completing the work as per these Specifications. It shall also include the cost of
providing flow drain pipes with all fixtures up to the point of ground drains wherever shown on the
drawings.
4.3 Open surface drains
4.3.1 General requirements
This Section covers the furnishing of materials and construction of slope stabilization and surface
erosion protection, scour protection and river training works required for bridge protection.
4.3.2 Scope
This item covers construction of lined trapezoidal or box drain of depth 450 mm and clear width of 800
mm including 150mm thick PCC M15:20 base, 300mm thick RRM on both sides in CM 1:4, including
excavation, leveling and disposal of surplus earth within 50m lead.
4.3.3 Excavation
Trenches shall be made along where the drain is to be constructed. The excavation shall be done
exactly to the required profile giving specified slope. The surface shall be levelled to uniform
grade/level and rammed.
For the lined drain the relevant specification for concreting, soling and plastering shall be followed.
The surface of the concrete shall be finished smooth. Any rough surface shall be made smooth by
adding dry mix of cement and sand 1:3 (1 cement: 3 sand) on the surface immediately after
concreting when the concrete is still green. No extra shall be paid for such finishes. All work shall be
carried out as per the drawing and specification or as directed by the Project manager.
The longitudinal slope of the drain must not be less than 3% and it should be uniform to avoid
ponding. The cross slope shall be as per drawing unless otherwise directed by the Project Manager.
All concrete and masonry work shall be thoroughly cured not less than 28 days before water is
allowed to flow in the drain. The clear internal dimension of the drain shall be 800 mm wide and 450
mm deep.
4.4 Measurement and Payment
The length shall be measured in running metre correct to 50mm.
The rates shall include the cost of all material, tools & plants and labour involved in the above
operation.
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
4.5 HDPE drainage pipes
4.5.1 Scope
This work shall consist of providing HDPE drainage pipes on the deck slab underneath the foot path
slabs (if they exist).
4.5.2 Material
All HDPE pipes shall comply with Indian Standard IS 13592 or ISO D1785:08 Standard Specification
for High Density Polythene pipe (HDPE) Plastic Pipes.
4.5.3 Placement
The pipes shall be placed in true position, lines and levels as shown in the drawing with necessary
cut-out in the shuttering for deck slab and held in place firmly. Where the reinforcements of the deck
are required to be cut, equivalent reinforcements shall be placed around the pipes. The ends of pipes
during construction shall be closed against the intrusion of foreign material.
4.6 Measurement and Payment
The drainage pipes shall be measured as number/piece for the shape, length, diameter, wall
thickness etc. shown in the drawings.
HDPE drainage pipes as shown in the drawings and defined in the BoQ, will be paid for at the
Contract unit price.
The price and payment shall constitute full compensation for furnishing all materials as indicated in
the Drawings including delivery, placement, finishing and for all labor, equipment, tools and
incidentals necessary to complete the work.
4.7 Gabion protection works
4.7.1 Scope
This Clause covers the furnishing of materials and construction of gabion works that may be required
to act as buttresses, retaining walls, catch walls, stream or river training structures, check dams within
gullies, or where placed as mattresses, to prevent stream or gully erosion.
4.7.2 Materials
4.7.2.1 Stones
Stones used for filling the gabion boxes or mattresses shall be clean, hard, sound, un-weathered and
angular rock fragments or boulders. The specific gravity of the stone shall be not less than 2.50 and
the stones shall not absorb water more than 5 percent when tested as per IS1124. The length of any
stone shall not exceed three times its thickness. The smallest dimension of any stone shall be at least
twice that of the longer dimension of the mesh of the crate. However smaller size of stones as spalls
shall be allowed for filling voids and its volume including voids shall not be more than 20 percent of
the total volume of the stones.
Before filling any gabion boxes and mattresses the Contractor shall submit representative samples of
the rock he proposes to use in the gabions for approval by the Project Manager. Further
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
representative samples shall be submitted for approval each time when there is a change in the type
and strength of the rock.
4.7.2.2 Gabions
Gabions shall consist of steel wire mesh crates. The steel wire shall be mild steel wire complying with
IS 280-197. All wires used in the manufacturing crates and diaphragms, binding and connecting lids
and boxes shall be galvanised with an heavy coating of zinc by an electrolytic or hot dip galvanising
process. The weight of deposition of zinc shall be in accordance with IS 4826-1979. Zinc coating shall
be uniform and be able to withstand minimum number of dips and adhesion test specified in IS 4826-
1979. Tolerance on diameter of wire shall be + 2.5 percent. The tensile strength of gabion wire shall
be between 300 and 550 N/mm2.
The wire shall be woven into a hexagonal mesh with a minimum of 3 twists. All edges of the crates
shall be finished with a selvedge wire at least 3 gauges heavier than the mesh wire. Gabions shall be
manufactured in the standard sizes shown in Table 4.1 with mesh and wire sizes as shown in Table
4.2.
Diaphragms shall be manufactured of the same materials as the parent gabion box and shall have
selvedge wire throughout their perimeter. The number and size of diaphragms to be provided with
each crate shall be as in Table 4.1. All crates shall be supplied with binding and connecting wire of the
gauges shown in Table 4.2 of sufficient quantity to bind all diaphragms and closing edges.
Table 4.1: Standard Size of Wire Mesh Gabions
Dimensions in metres
(Prior to fill)
Number of diaphragms
Dimensions of diaphragms in metres
Volume of crate in cubic metres
1 x 1 x 1 - - 1
1.5 x 1 x 1 1 1 x 1 1.5
2 x 1 x 1 1 1 x 1 2
3 x 1 x 1 2 1 x 1 3
1 x 1 x 0.75 - - 0.75
2 x 1 x 0.75 1 1 x 0.75 1.5
3 x 1 x 0.75 2 1 x 0.75 2.25
1 x 1 x 0.5 - - 0.5
2 x 1 x 0.5 1 1 x 0.5 1
3 x 1 x 0.5 2 1 x 0.5 1.5
1 x 1 x 0.3 - - 0.3
2 x 1 x 0.3 1 1 x 0.3 0.6
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
3 x 1 x 0.3 2 1 x 0.3 0.9
Table 4.2: Standard Sizes of Mesh and Wire in Gabions
Mesh
opening mm
Mesh type Thickness of
mesh wire
Thickness of
binding and
connecting wire
Thickness of
selvedge
wire
(DxH) S.W.G. S.W.G. S.W.G.
83x114 80x100 9,10,11 11,12,13 6,7,8
114x128 100x120 10,9 12,11 7,6
The mesh opening shall be as instructed by the Project Manager.
Equivalent diameter in mm
SWG 6 7 8 9 10 11 12 13 14
mm 4.88 4.47 4.06 3.66 3.25 2.95 2.64 2.34 2.03
Construction of Gabions
4.7.2.3 General Requirements
Before filling any gabion boxes and mattresses, the Contractor shall submit samples of gabion boxes
and/or gabion mattresses assembled, erected and filled with stones for approval which, when
approved, shall be retained for reference and comparison with the gabions built as part of the
permanent works. The size, type and location of the samples shall be as directed by the Project
Manager.
Gabion boxes and gabion mattresses shall be assembled, erected and filled with stones in the dry on
prepared surfaces except as may be otherwise approved. Approval for assembling and erecting
gabions in water shall be given only, if in the Project Manager's opinion such a method will produce
work which is otherwise in accordance with the Specification.
4.7.2.4 Preparation of Foundation & Surface for Bedding
The bed on which the gabion boxes or mattresses are to be laid shall be even and conform to the
levels shown on the Drawing. If necessary, cavities between rock protrusions shall be filled with
material similar to that specified for gabion filling.
4.7.2.5 Arrangement of Joints
(a) Walls
In walls, gabion boxes shall be placed such that vertical joints are not continuous, but staggered.
Aprons shall be formed of headers. If more than one unit is required to obtain the necessary width,
units of unequal length shall be used and the joints between them should be staggered.
(b) Channel linings
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
In channel linings, gabion box and mattress units shall be laid so that the movement of stone inside
the mesh due to gravity or flow of water is avoided. Hence, on side slopes, units shall be placed with
their internal diaphragms at right angles to the direction of the slope and, on inverts, as far as
possible, at right angles to the direction of flow.
(c) Assembly
Gabion boxes and gabion mattresses shall be assembled on a hard flat surface. After fabrication,
unpacking or unfolding, they shall be stretched out and any kinks shall be removed. Creases shall be
in the correct position for forming the boxes or mattress compartments. The side and end panels shall
be folded into an upright position to form rectangular boxes or compartments. The top corners shall be
joined together with the thick selvedge wires sticking out of the corners of each panel. The tops of all
sides and partitions shall be leveled except as may be appropriate to special units. The sides and end
panels shall be tied together using binding wire of the thickness given in Table 25.2, starting at the top
of the panel by looping the wire through the corner and twisting the wire together. Binding shall
continue by looping the wire through each mesh and around both selvedges with three rounds which
shall be joined tightly together by twisting and the end shall be poked inside the unit. The diaphragms
shall be secured in their correct positions by binding in the same way. The bindings wire shall be fixed
using 250mm long nose fencing pliers or equivalent approved tools.
The gabion boxes and gabion mattresses shall be laid in such a manner that the hinges of the lid will
be on the lower side on slopes and on the outer side in walls.
Where mattresses are laid horizontally hinges shall not be placed on the downstream side as much as
practicable.
(d) Filling
The crates shall be placed in their final position before filling commences. They shall be stretched to
their full dimension and securely pegged to the ground or wired to adjacent gabions before filling. The
vertical corners shall be kept square and to full dimension by inserting a steel bar of at least 20 mm
diameter at each vertical corner, maintaining it in the correct final position throughout the filling
process, and removing it when the crate is full. Before filling commences, the selvedges of the crate
shall be bound to the selvedges of adjacent crates with binding wire. Where crates are being
assembled in position in a wall the binding of the edges of each crate in the assembly process and the
binding together of adjacent crates shall be carried out in the same operation.
Before filling with stone, gabions shall be anchored at one end or side and stretched from the opposite
end or side by inserting temporary bars and levering them forward, The top and bottom shall be kept
stretched by tensioning with tie wires attached to an anchorage or equivalent approved method until
the gabion has been filled. The gabions shall be inspected at this stage but before filling with stone to
ensure that the tie/wiring has been properly carried out and the gabion boxes or gabion mattresses
are not pulling apart. Gabion boxes or gabion mattresses may be tensioned either singly or in the
case of a long straight structure by straining a number of units together using an approved tensioning
system.
The filling shall be carried out by placing individual stones into the gabion by hand in courses in such
a manner that the stones are bedded on each other and bonded as in dry random rubble masonry as
per Clause 1308. No loose stones shall be tipped into the crate and the practice of coursing and
bonding the outer layer and filling the interior with unlaid stones shall not be permitted.
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
All 1m deep gabions shall be filled in three equal layers and 0.5m deep gabions in two equal layers.
Horizontal bracing wires made with the same bindings wire as used for tying shall be fixed directly
above each layer of the stone in the compartments, the wires being looped round two adjoining
meshes in each side of the compartment and joined together to form a double tie which shall be
tensioned by wind lassing together to keep the face of the gabions even and free from bulges. Bracing
wires shall be spaced horizontally along and across the gabions at distances not greater than 0.33m.
Where the upper faces of gabion boxes are not covered with further gabions vertical bracing wires
shall be fitted between the top and bottom mesh using two tie wires per square metre of surface.
The ties shall be fixed to the bottom of the units prior to filling and tied down to the lid on completion.
Where a double layer of gabion boxes is used to form an apron both upper and lower layers shall
have vertical tie wires.
(e) Securing Lids
The gabion boxes and mattress compartments shall be over filled by 50mm above their tops to allow
for subsequent settlement. The lids shall then be tied down with binding wire to the tops of all partition
panels. The lids shall be stretched to fit the sides exactly by means of a suitable tool but due care
shall be taken to ensure that the gabions are not so full that the lids are overstretched. The corners
shall be temporarily secured first.
(f) Tolerance
On completion, the crates shall be completely and tightly filled, square, true to dimensions and the line
and level shown on the Drawing. However the tolerance limit permitted in the length, height and width
of the gabion boxes and mattresses as manufactured shall be 3 percent from the ordered size prior
to filling. The tolerances on the wire mesh opening shall be 10% on the nominal dimension 'D'
values as follows:
Mesh type Nominal dimension 'D' values
80x100 83
100x120 114
However, the number of opening per gabion box/mattress shall not be less than the nominal length
divided 'D' on horizontal direction and nominal height divided by 'H' in vertical direction where D and H
are as per Table 4.5.
4.7.2.6 Test & Standard of Acceptance
(1) The gabion wire shall be tested for mass, uniformity and adhesion of zinc coating and tensile
strength of the wire itself. Failure of test results to comply with the specifications shall lead to
the rejection of gabion wires. The test on the samples taken as per Table 15.3 from each lot
of the G.I. wire received at the side of the work shall be carried out in accordance with IS 280-
197 and IS 4826-1979.
Table 15.3: Scale of Sampling and Permissible Number of Defective
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
No. of coils in a lot No. of coils randomly
selected for sampling*
Permissible No. of
defective coil
Up to 25 2 0
26-50 3 0
51-150 5 0
151-300 8 1
300 and above 13 1
* One sample per coil shall be tested in all respect.
(2) The stones shall be tested for water absorption. At least 3 set of tests shall be made for every
source of material. The test results shall meet the specified criteria.
4.8 Measurement and Payment
Measurement shall be in cubic meters of gabion crates filled with stones and complete in place and
quantity shall be calculated from the dimension of the gabions indicated in the Drawing or ordered by
the Project Manager.
Payment shall be made as per respective contract unit rate which shall be the full and the final
compensation to the Contractor as per Clause 115 to complete the work in accordance with these
Specifications.
4.9 Elastomeric Bridge Bearings
4.9.1 Scope
The purpose of bridge bearing is to spread the load over a pre-determined area of beam above and of
the pier and abutment below, while permitting an adequate amount of elastic and temperature
movements. The degree of sophistication needed in a bearing will depend on the load to be carried
and the number of movements (e.g. translations and rotations) to be allowed for; also for the lateral
forces to be resisted in a direction at right angles to the primary movements.
Design life of bearing is not generally as long as the bridge. Provision must be made for their
replacement as well as their regular inspection. This requires that the bridge can be jacked up and
that bearings can be removed without too much difficulty.
4.9.2 Steel reinforced Elastomeric Bearings
An elastomeric bridge bearing is a device constructed partially or wholly from elastomer. The purpose
of this is to transmit loads and accommodate movements between a bridge superstructure and its
supporting structure. Steel-reinforced elastomeric bearing shall consist of alternate layer of steel
reinforcement and elastomer bonded together. In addition to any internal reinforcement, bearings may
have external steel load plated bonded to either or both the upper or lower elastomer layers.
Bearings should be furnished with dimensions, material properties, elastomer grade and type of
laminates required by the drawings.
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Construction ,Operation & Maintenance of Dalbari-Odalthang SNH (Section A: 0.000 -29.000 Km)
4.9.3 Properties of Elastomer
The raw elastomer shall be either virgin Neoprene (polychloroprene) or virgin natural rubber
(polyisoprene). The elastomer compound shall be classified as being of low temperature grade. The
elastomer shall have a shear modulus between 0.9 and 1.3 MPa. It shall conform to the requirements
of IRC:83 (Part II).
4.9.4 Steel Laminates
Steel laminates used for reinforcement shall be made from rolled mild steel conforming to IS 2062 or
ASTM A36, A570 or equivalent unless otherwise specified by the Project manager. The laminates
shall have a minimum thickness as shown on the drawings. Holes in plates for manufacturing
purposes will not be permitted unless they have been accounted for in the design and shown on the
drawing.
4.9.5 Bond
The vulcanised bond between elastomer and reinforcement shall have a minimum peel strength of 5.2
kN/m. Steel laminated bearings shall develop a minimum peel strength of 6.9 kN/m.
4.9.6 Manufacture
Bearing with steel laminates shall be cast as a unit in a mould and shall be bounded and vulcanised
under heat and pressure. The mould finish shall conform to standard shop practice. The internal steel
laminates shall be sand blasted and cleaned of all surface coatings, rust, mill scale, and dirt before
bonding, and shall be free from sharp edges and burrs. Bearings that are designed to act as a single
unit with a given shape factor must be manufactured as a single unit.
4.9.7 Fabrication Tolerances
Plain pads and laminated bearings shall be built to the specified dimension within the following
tolerances:
Design Thickness 32mm (1¼ in.) or less - - 0, + 3mm
Design Thickness over 32mm - - 0, + 6mm
Overall Horizontal Dimension 914mm (36 in.) or less - - 0, + 6mm
Thickness of Individual Layers of ± 20% of design
Elastomer (Laminated Bearings only) value but not
At any point within the bearings more than ± 3mm
Parallelism with opposite face - 0.005 radian
Top and bottom sides - 0.02 radian
Edge Cover -
Embedded Laminates - - 0, + 3mm
Thickness -
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Top and bottom cover Layer - - 0, the smaller of + 1.5mm and + 20% of
the nominal cover layer
thickness.
4.9.8 Marking and Certifying
The manufacturer shall certify that each bearing satisfies the requirements of the drawings and these
specifications, and shall supply a certified copy of material test results. Each reinforced bearing shall
be marked with indelible ink or flexible paint the bearing identification number, elastomer type and
grade number. The marking shall be on the face that is visible after erection of the bridge.
4.9.9 Testing
i) General
Materials for elastomeric bearings and the finished bearings themselves shall be subjected to the
tests described in the drawings.
ii) Ambient Temperature Tests on the Elastomer
The elastomer used shall at least satisfy the limits prescribed in the AASHTO for durometer hardness,
tensile strength, ultimate elongation, heat resistance, compression set, and ozone resistance. The
bond to the reinforcement, if any, shall also satisfy the requirement of Article 4.9.5 above. The shear
modulus of the material shall be tested at 23°c (73°F) using the apparatus and procedure described in
Annexure A of ASTM D4014. It shall be either equal to or greater than the value shown on the
drawing.
iii) Visual Inspection of the Finished Bearing
Every finished bearing shall be inspected for compliance with dimensional tolerances and for overall
quality of manufacture. In steel reinforced bearings, the edges of the steel shall be protected
everywhere from corrosion.
iv) Short Duration Compression Tests on Bearings
The bearing shall be loaded in compression to 1.5 times the maximum design load. The load shall be
held constant for 5 minutes, removed, and re-applied for another 5 minutes. The bearing shall be
examined visually while under the second loading. If the bulging pattern suggests laminate parallelism
or a layer thickness that is outside the specified tolerances, or poor laminate bond the bearing shall be
rejected. If there are three or more separate surface cracks that are greater than 0.2mm (0.08 in.)
wide and 0.2mm (0.08 in.) deep, the bearing shall be rejected.
v) Long-Duration Compression Tests on Bearings
The bearing shall be loaded in compression to 1.5 times its maximum design load for a minimum
period of 15 hours. If, during the test, the load falls below 1.3 times the maximum design load, the test
duration shall be increased by the period of time for which the load is below this limit. The bearing
shall be examined visually at the end of the test while it is still under load. If the bulging pattern
suggests laminate parallelism or a layer thickness that is outside the specified tolerances or poor
laminate bond the bearing shall be rejected. If there are three or more separate surface cracks that
are greater than 0.2mm (0.08 in.) wide and 0.2mm (0.08 in.) deep, the bearing shall be rejected.
vi) Shear Modulus Tests on Material from Bearings
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The shear modulus of the material in the finished bearing shall be evaluated by testing a specimen cut
from it using the procedure given in annex A of ASTM D4014. If the test is conducted on finished
bearings, the material shear modulus shall be computed from the measured shear stiffness of the
bearing, taking due account of the influence on shear stiffness of bearing geometry and compressive
load.
4.9.10 Installation
Bearings shall be placed on surfaces that are plane to within 1.5mm (1/16 in.) and horizontal to within
0.01 radian. Any lack of parallelism between the top of the bearing and the underside of the girder that
exceeds 0.01 radian shall be corrected by grouting or as otherwise directed by the Project manager.
In order to function correctly the elastomeric bearings must be placed with particular care.
As a general rule, the bearings must be placed on a perfectly plane and horizontal surface. A 30 to 40
mm high mortar pad or for larger height the RC pad is cast onto the base concrete, which must be
previously carefully roughened. The dimensions of the pad must be by 30 to 50 mm larger than those
of the bearing.
When minimum loads are small, it is recommended to glue the bearing to the support with an epoxy
resin.
The bottom face of the pre-cast unit, in contact with the bearing, must be perfectly plane and
horizontal.
For cast-in-situ structures, the bearing is placed on the support and the structure cast on the bearing.
The shuttering surrounding the bearing must be removable at the time of stripping the forms and at
the same time it must be strong enough to resist the weight of concrete. If the base shuttering fails,
the bearing will be partially embedded in the concrete and the distortions hindered. Future lifting of the
structure may become more difficult.
4.10 Measurement and Payment
Elastomeric bearing is measured by the total number of complete bearing installed at the specified
bridge location.
Elastomeric bearing measured in accordance with Section 4.10 shall be paid for at the Contract unit
prices for providing bearings in the locations indicated on the Drawings and described in the Bill of
Quantities. Payment shall be full compensation for furnishing and installing all materials, including all
labor, tools, equipment and incidentals necessary to complete the work.
4.11 Movement or Expansion Joints
4.11.1 Scope of Work
The scope of work will include:
i) Preparation of detailed engineering and installation drawings, supply and supervision during fixing of
strip seal/compression seal expansion joints conforming to specifications. The expected
expansion/contraction of the superstructure at the location of expansion joints are shown in relevant
approved drawings.
ii) Design manufacture, providing and seating of expansion joints by the specialized agency and
approved by the Project manager.
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iii) Necessary technical supervision for installation of each and every expansion joint during different
stages of installation including rectification of any deficiency or defect attributable to fixing and
installation will be provided by the manufacturer/supplier. The expansion joint shall be provided for the
full width of bridge including the railing. Leak tightness of all joints shall be ensured.
4.11.2 Specification for Strip Seal Expansion Joint
Expansion joint type described here–after is the “strip seal type”, but alternate designs can be
proposed for the Project manager’s approval.
4.11.2.1 Components:
Strip seal expansion joint shall comprise the following items:
a) Edge beam:
This shall be either extruded or hot rolled steel section or cold rolled cellular steel section with suitable
profile to mechanically lock the swelling element in place throughout the normal movement cycle.
Further the configuration shall be such that the section has a minimum thickness of 10 mm all along
its cross section (flanges and web) the minimum height of the edge beam section shall be 50 mm and
the minimum cross sectional area of the edge beam shall be 1500 sq.mm.
b) Anchorage:
Edge beams shall be anchored to the deck/dirt wall/approach slab by reinforcing bars or bolts or
anchor plates cast in concrete or a combination of anchor plate and reinforcing bars. Anchor bars
studs or bolts shall engage the main structural reinforcement of the deck and in case of anchor plates
or loops, this shall be achieved by passing transverse bars through the loops or plates.
The minimum thickness of anchor plate shall be 12 mm. Total cross sectional area of bar on each
side of the joint shall not be less than 1600 sq.mm per meter length of the joint and the center to
center spacing shall not exceed 250 mm. The ultimate resistance of anchors shall not be less than
600 kN/m in any direction.
4.11.2.2 Material
a. The steel for edge beams shall conform to any of the steel grade corresponding to RST 37-2 or 37-3 (DIN), ASTM A 36 or A 588, CAN/CSA standard G40.21 Grade 300W or equivalent. b. Anchorage steel shall conform to IS: 2062 or equivalent.
c. All steel sections shall be protected against corrosion by hot dip galvanizing or any other approved
anticorrosive coating with a minimum thickness of 100 micron.
d. Chloroprene of strip seal element shall conform to clause 9151.1 of IRC:83 (Part-ll) The properties
of chloroprene shall be as specified in Table 4.11-1
4.11.2.3 Fabrication (Pre-installation)
a. The strip seal joint system and all its component parts including anchorages shall be supplied by
the manufacturer/ system supplier.
b. The width of the gap to cater for movement due to thermal effect, pre stress, shrinkage and creep,
superstructure deformations (if any) and sub-structure deformations (if any) shall be determined and
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intimated to the manufacturer depending upon the temperature at which the joint is to be installed, the
gap dimension shall be preset.
Table 4.11-1 Strip Seal Element Specifications
Sl. No Property Specified Value
1 Hardness 63+/- shore A
2 DIN 53505 55+/- Shore A
3 ASTM D (Modified)
4 Tensile strength Min. 11 MPa
5 DIN 53504 Min. 13.8 MPa
6 ASTM D412
7 Elongation at fracture Min. 350 per cent
8 DIN 53504 Min. 250 per cent
9 ASTM D412
10 Tear Propagation strength Min. 10 N/mm
11 Longitudinal Min. 10N/mm
12 Transverse Min. 25 per cent
13 Shock elasticity Min 220 Cu. mm
14 Abrasion
15 Residual compressive strain (22/70 deg C/30 per cent)
Aging in hot air (14 days/70 degC)
Max. 28 per cent
16 Change in hardness Max. +7 Shore A
17 Change in tensile strength Max. -20 per cent
18 Change in elongation at fracture -20 per cent
19 Aging in ozone (24h/50pphm/25 deg per cent
elongation)
No cracks
20 Swelling behaviour in oil (168h/28 deg/C)
21 ASTM Oil No. 1 Max. +5 per cent
22 Volume Change Max. -20 Shore A
23 Change in hardness Max. -35 deg C
24 ASTM Oil No. 3 Max. +25 per cent
25 Volume change Max. -25 Shore A
26 Change in hardness Max. -35 deg C
27 Cold Hardening Point
c. Each strip seal expansion joint system shall be fabricated as a single entity unless stage
construction or excessive length prohibits monolithic fabrication. It shall fit the full width of the
structure as indicated on the approved drawing. The system shall be pre-set by the manufacturer prior
to transportation. Presetting shall be done in accordance with the joint opening indicated on the
drawing.
d. The finally assembled joint shall them be clamped and transported to the work site.
4.11.2.4 Handling and Storage
a. For transportation and storage, auxiliary brackets shall be provided to hold the joint assembly
together.
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b. The manufacture/ supplier shall supply either directly to the Project manager or to the Bridge
Contractor all the materials of strip seal joints including sealants and all other accessories for the
effective installation of the jointing.
c. Expansion joint material shall be handled with care. It shall be stored under cover on suitable
lumber padding.
4.11.2.5 Supply/ Installation
Components of expansion joint such as edge beam and strip seal shall be arranged by the contractor
by procuring the same from reputed approved manufacturer to ensure quality and performance.
Contractor shall furnish a warranty of trouble free performance for at least ten years and free
rectification of defects / replacement, if any, during this period.
The joints shall be installed in compliance to the manufacturer’s instructions for installation.
Taking the width of gap for movement of the joint into account the dimensions of the recess in the
decking shall be established in accordance with the drawings or design data of the manufacturer. The
surfaces of the recess shall be thoroughly cleaned and all dirt and debris removed. The exposed
reinforcement shall be suitably adjusted to permit unobstructed lowering of the joint into the recess.
The recess shall be shuttered in such a way that dimensions in the joint drawing are maintained. The
formwork shall be rigid and firm.
Immediately prior to placing the joint, the presetting shall be inspected. Should the actual temperature
of the structure be different from the temperature provided for presetting, correction of the presetting
shall be done. After adjustment the brackets shall be tightened again.
The joint shall be lowered in a pre-determined position. Following placement of the joint in the
prepared recess, the joint shall be leveled and finally aligned and the anchorage steel on one side of
the joint welded to the exposed reinforcement bars of the structure. Upon completion, the same
procedure shall be followed for the other side of the joint. With the expansion joint finally held at both
sides, the auxiliary brackets shall be released allowing the joint to take up the movement of the
structure.
High quality concrete shall then be filled into the recess. The packing concrete must feature low
shrinkage and have the same strength as that of the superstructure but in any case not less than M30
grade good compaction and careful curing of concrete is particularly important.
After the concrete has cured, the movable installation brackets and shuttering still in place shall be
removed.
The neoprene seal shall be field installed in continuous length spanning the entire roadway width. To
ensure proper fit of seal and enhance the ease of installation dirt, spatter or standing water shall be
removed from the steel cavity using a brush, scrapper or compressed air. The seal shall be installed
without any damage to the seal by suitable hand method or machine tools.
The deck surfacing shall be finished flush with the top of the steel sections, the horizontal leg of the
edge beam shall be cleaned beforehand. It is particularly important to ensure thorough and careful
compaction of the surfacing in order to prevent any premature depression forming in it.
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4.11.2.6 Acceptance criteria
a. All steel elements shall be finished with corrosion protection system
b. For neoprene seal, the acceptance test shall conform to the requirements stipulated in Table
4.11-1. The manufacturer/ supplier shall produce a test certificate accordingly, conducted in a
recognized laboratory, in India or abroad.
c. The manufacturer shall produce test certificates indicating that anchorage system had been tested
in recognized laboratory to determine optimum configuration of anchorage assembly under dynamic
loading.
d. Prior to acceptance 25 percent of the completed and installed joints, subject to a minimum of one
joint, shall be subjected to water tightness test. Water shall be continuously pounded along the entire
length for a minimum period of 4 hours for a depth of 25mm above the highest point of deck. The
width of ponding shall be at least 50mm beyond the anchorage block of the joint on either side. The
depth of water shall not fall below 25mm anytime during the test. A close inspection of the underside
of the joint shall not reveal any leakage.
e. As strip seal type of joint is specialized in nature, generally of the proprietary type, the manufacturer
shall be required to produce evidence of satisfactory performance of this type of joint.
4.11.2.7 Test and standards or acceptance:
The materials shall be tested in accordance with these specifications and shall meet the prescribed
criteria. The manufacturer/supplier shall furnish the requisite certificates from the recognized
laboratory in India or abroad.
4.12 Measurement and Payment
Expansion joints shall be measured by the linear Meter of complete joint installed, measurement
being along a straight line from base to top of a wall or one side of a slab to the other, etc. The
measured length may therefore include a sealant length of over twice this value if several faces of the
concrete are sealed.
Expansion joints measured in accordance with Section 4.12 shall be paid for at the Contract unit
prices for providing joints in the locations indicated on the Drawings and described in the Bill of
Quantities. Payment shall be full compensation for furnishing and installing all materials, including all
labor, tools, equipment and incidentals necessary to complete the work.
5.0 SECTION 5: DAY WORKS
5.1 General
Work shall not be executed on a Daywork basis except by written order of the Project Manager. Bidders shall enter basic rates for Daywork items in the Schedules, which rates shall apply to any quantity of Daywork ordered by the Project Manager. Nominal quantities have been indicated against each item of Daywork, and the bidders must provide competitive rates for each item.
5.2 Dayworks Labour
In calculating payments due to the Contractor for the execution of Daywork, the hours for labour will be reckoned from the time of arrival of the labour at the job site to execute the particular item of Daywork to the time of return to the original place of departure, but excluding meal breaks and rest
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periods. Only the time of classes of labour directly doing work ordered by the Project Manager and for which they are competent to perform will be measured. The time of gangers (charge hands) actually doing work with the gangs will also be measured but not the time of foremen or other supervisory personnel.
The Contractor shall be entitled to payment in respect of the total time that labor is employed on Daywork, calculated at the rates quoted in the Daywork of BOQ. The rates for labor shall be deemed to cover all costs to the Contractor including (but not limited to) the amount of wages paid to such labor, transportation time, overtime, subsistence allowances, and any sums paid to or on behalf of such labor for social benefits in accordance with law of Kingdom of Bhutan, as well as Contractor's profit, overheads, superintendence, liabilities and insurance and allowance to labor, timekeeping and clerical and office work, the use of consumable stores, water, lighting and power; the use and repair of staging, scaffoldings, workshops and stores, portable power tools; supervision by the Contractor's staff, foremen and other supervisory personnel; and charges incidental to the foregoing. The rates shall be stated in the local currency.
5.3 Dayworks Materials
The Contractor shall be entitled to payment in respect of materials used for Daywork (except for materials for which the cost is included in the percentage addition to labour costs as detailed heretofore), at the rates entered by him in the Materials section of Daywork, and shall be deemed to include overhead charges and profit as follows;
(a) the rates for materials shall be calculated on the basis of the invoiced price, freight,
insurance, handling expenses, damage, losses, etc., and shall provide for delivery to store for stockpiling at the Site. The rates shall be stated in local currency.
(b) the cost of hauling materials for use on work ordered to be carried out as Daywork from the
store or stockpile on the Site to the place where it is to be used will be paid in accordance with the terms for labor and Constructional Plant in this Schedule.
5.4 Dayworks Plant
The Contractor shall be entitled to payments in respect of Construction Equipment already on Site and employed on Dayworks at the rental rates entered by him in the Construction Plant section of Dayworks. The said rates shall be deemed to include due and complete allowance for depreciation, interest, indemnity, and insurance, repairs, maintenance, supplies, fuel, lubricants, and other consumables, cost of drivers, operation and assistants and all overhead, profit, and administrative costs related to the use of such equipment.
In calculating the payment due to the Contractor for Construction Plants employed on Dayworks, only the actual number of working hours will be eligible for payment.
The rental rates for Constructional Plant employed on Dayworks shall be stated in local currency.