84102199 Construction Measurement III Week 3 Precast Pre Stressed Concrete

Construction Measurement III(SBQ 3314) Pre-Cast and Pre-Stressed Concrete Lecture By Dr Sarajul Fikri Mohamed

Department of Quantity Surveying, FAB, UTM Skudai Johor, Malaysia

29th December 2009

Pre-cast and Pre-stressed Concrete CIVIL WORKS

Electrical Installations

Fire Fighting Installations

Air Conditioning Installations

Unit/Split Package/Central

Landscape Works

Single Phase Three Phase

Gas Installations

ELECTRICAL WORKS

MECHANICAL WORKS

LANDSCAPE WORKS

Hard Landscape Soft Landscape

MAIN COURSE COMPONENTS

© 2009 Sarajul Fikri Mohamed

• Read and check drawing

• Drawing numbering and scale

used.

• Taking off list

• Heading and Description

• Take off

• Annotation / Side Cast

• Query list

• Final checking

BQs FOR PRECAST &

PRESTRESSED WORKS

PROJECT DRAWINGS

Output

3

• Construction technology

• Measurement rules: SMM2

• Description

• Taking Off

• Case Study

KNOWLEDGE

Measurement rules

PRE-CAST & PRE-STRESSED CONCRETE


Table of contents

1. Prestressed concrete in bridgeworks: technological aspects

2. SMM2 measurement rules for pre-cast and pre-stressed concrete

3. Taking off list for pre-stressed concrete

4. Heading and description.

5. Case study: Foot bridge pre-cast and pre-stressed concrete beam

6. Studio work of 'Membina Lebuh Raya Pesisir Pantai Dari Johor

Bahru ke Nusajaya' project.


Prestressed concrete in bridgeworks

Types of material # 1

BRIDGEWORKS

Concrete Steel

Masonry Timber

i Simply Supported

ii Continuous

iii Cantilever

System structure #1

BRIDGEWORKS

iv Arch

v Truss

vi Frame

System structure # 2

BRIDGEWORKS

vii Cable Stayed

viii Suspension

ix Culvert

System structure # 3

BRIDGEWORKS

i Reinforced concrete beam

ii Precast reinforced concrete

beam

iii Prestressed concrete beam

Deck types

BRIDGEWORKS

iv Concrete Box Girder

v Voided Concrete Slab

Deck types # 1

BRIDGEWORKS

14

Principles


Without pressing blocks together

With blocks pressed together

15

1) Precast concrete beam 2) Ducting 3) Vents 4) Tendons 5) Anchorages 6) Filling to anchorage pockets 7) Construction joint 8) Temporary support

Pre-cast & pre-stressed concrete

COMPONENTS

16


PRE-CAST CONCRETE BEAM

Prestressed concrete beams includes: cast in situ or pre cast, beams or box girders, simply supported or cable stayed.

Two main types which include:

PRE-TENSIONING

The tendon is stressed by jacking against an anchor frame before the concrete is placed.

POST-TENSIONING

The tendon is pulled and stretched using a jack and the resulting force is transferred directly on the hardened concrete through the tender anchor.

Cast in situ beam for construction of a bridge

Pre cast concrete beam from factory transported to site

18


WIRES

Individual wires are used in pre-tensioned beams but have become less common in favour of strand; which has better bond characteristics.

Wire diameters are typically between 5mm to 7mm, with a minimum tensile strength of between 1570 and 1860 N/mm2 carrying forces up to 45kN.

WIRE

19


STRANDS AND TENDONS The common pre-stressing is 7 wire

strand; made up of individual cold-drawn wires with six outer wires twisted around an inner core wire

For post tensioning, 13mm or

15mm diameter, 7 wire strand is used, either singly for pre-tensioning or in bundles to form multi strand tendons.

The common post-tensioned tendon sizes utilize 7, 12, 19 or 27 strands.

Multi strand tendon live-end

anchor

20

Tendons consists of seven cables

7 wires strand

21


DUCTING A duct is used to form a void

through the concrete into which the tendon is placed.

Ducts are made from corrugated steel covered by BS EN523 (1997) with a wall thickness of 0.25mm

Meanwhile, corrugated plastic ducts also cal be used with a wall thickness of 2.5mm to 3.0mm thickness.

External tendons are usually placed inside high-density polyethylene (HDPE) ducts.

Steel duct

22

Ducts and cables for stressing process

23


ANCHORAGES # 1 For pre-tensioned strands the

anchorage is by bond and friction of the bare strand cast into concrete

For post-tensioned tendons,

anchorage is achieve by using anchor blocks or an encased dead-end anchor.

Stressing of multi-strand tendons is undertaken using jacks placed over the anchorage and tendon. The jack grips each strand and pulls the tendon until the required force is generated.

Multi strand tendon live-end

anchor

24


ANCHORAGES : BEARING PLATE #2

25


ANCHORAGES # 3

26


EQUIPMENT FOR PLACING TENDONS # 1 For larger and longer multi-strand tendons, special equipment is needed to

position the strand.

In a multi-strand tendon, the strands are positioned by either pushing or pulling the strand into place.

The push-through method involves pushing individual strands into the duct one at a time until the number is in position.

The pull-through method is strands are first cut to length and bundled into a complete tendon at one end of the duct. A steel pulling rope is thread through the duct and connected to a winch at one.

The push-through method

The pull-through method

28


THE PUSH THROUGH METHOD

29


THE PULL THROUGH METHOD

30


STRESSING JACKS The jacks are hydraulically operated

with oil pumped into the piston to apply load to the tendon.

The larger jacks can generate a pulling force in excess of 1200 tonnes. The same jacks are also used to de-stress tendons.

For de-stressing, special tools are used to move the jack back and to give access to the anchor wedge or nut allowing them to be loosened or removed.

Stressing jack

31

Tensioning works in progress

Tendons stressing work are completed

33


GROUTING AND VENTS # 1 Grouting mixing on site and these are used to mix the cement, water and

any admixtures required to give a homogeneous grout.

The post-tensioning system have a large hole in the bearing plate to allow the grout to be pumped in via the anchorage cap.

Inlet tubes are needed to allow the grout to be pumped into the duct and should have a minimum internal diameter of 25mm.

A grout pump combined with the mixing pans takes the fluids grout from the pans and pushed it into the duct via the inlet.

All grouting equipment should be duplicated on site to ensure that back-up is always available in case of breakdowns.

Grouting

34


GROUTING AND VENTS # 2

Grouting equipment includes mixer and pump in one unit.

Grouting is usually carried out as soon as possible after stressing.

35


GROUTING AND VENTS # 3 Outlet tubes are required to vent off the air and to ensure the ducts are full of

grout.

Vents are provided at each low point, both to drain out any standing water and to draw off any trapped air.

A vent is provided at the ‘far’ end of the duct to ensure that the duct is filled along its full length.

Vents should be provided at regular intervals along ducts with long ‘flat’ profiles to remove trapped air that can occur as the grout runs along the bottom of the duct. The maximum vent spacing is less than 15m.

Vent tube

VIDEO PRESENTATION

PROJECT

I-85 BRIDGE, LAGRANGE,

GEORGIA, USA.

Fakulti Alam Bina


SMM2 measurement rules

Measurement rules


39

Related clauses


Clause Description

F.34 F.41-45 F.26 F.35 F.1-7 F.36 F.8-9 F.37 F.10-16 F.38 F.17 F.21 F.23 F.39 F.40

Generally (Prestressed concrete work) Contractor-designed construction Generally (Composite construction) In-situ concrete members Generally (In-situ concrete) Reinforcement to in-situ concrete members Reinforcement Formwork to in-situ concrete members Formwork Precast concrete units Generally (Precast concrete) Standard or purpose-made units Temporary supports Ducts, grooves and pockets Prestressed tendons

40

F.34 GENERALLY

Concrete members classified as prestressed concrete works where a stress is artificially induced in the concrete by means of tendons tensioned working load are applied.

Prestressed concrete work and its reinforcement and associated formwork shall be given under an appropriate heading.

Measurement rules


41

F.34 GENERALLY

Work required to be designed by the Contractor shall be given in accordance with clauses F.41-45.

Work of composite construction shall be given in accordance with clause F.26

Measurement rules


Lifting of pre-cast concrete beams

Launching of pre-cast beam to the column piers

Cast in-situ pre-stressed concrete beams

44

Pre-stressed concrete beams deliver to site

Loading of pre-stressed concrete beams

PRESTRESSED CONCRETE WORK F.34 Generally

A brief description of the prestressed work stating the method of

tensioning shall be given.

• Location drawings showing the prestressing arrangements shall be provided except where stress is to be applied over the full length of a concrete member by means of continuous tendons running between the ends of the member.

Measurement rules


47

Multistrand system

PRE-CAST & PRE-STRESSED CONCRETE A brief description of the pre-stressed work

48

Standardized tendon units with up to 55 strands of 13mm (0.5”) or 15mm

(0.6”) diameter.

Ducts of steel or polythelene

Grouting with cements mortar or other materials.

Simultaneous stressing of all strands in a tendon but individual locking of

each at the anchorage.

Stressing in any number of steps.

VSL multistrand system components


49

VSL external post tensioning system


50

VSL monostrand system


51

Multistrand system

PRE-CAST & PRE-STRESSED CONCRETE Location drawings showing the pre-stressing arrangements shall be provided

52

PRESTRESSED CONCRETE WORK F.34 GENERALLY

Except in the case of standard or stock-pattern members particulars of the following shall be given: a. Materials of which the wires are composed, their diameters and details of any preparatory treatment. b. Numbers of wires to be tensioned simultaneously. c. Amount of tension to be applied to the wires. d. Strength of concrete required at transfer of stress. e. Tests. f. Cutting off and treating the ends of wires.

Measurement rules


53

Types of tendon

1. Wire

2. Standard strand

3. Drawn strand

4. Cable of seven strands

5. Dividing bar

6. Macalloy bar

Types of tendon


54

Typical tendon format


55

Structure of monostrand


56

Two, three and seven wire strands

Number of wire strands


© 2009 Sarajul Fikri Mohamed 57

Akashi Kaiyo Bridge Japan


58

Cable Details


CABLE DETAILS

59


CABLE SPECIFICATIONS

60


STRAND INSTALLATIONS

61

PRESTRESSED CONCRETE WORK F.34 GENERALLY

Where tendons are tensioned after the concrete is cast (post-tensioned) particulars of the following shall be given: a. The type of jack used. b. Details of anchorages and anchorage fittings. C. Whether tensioning is carried out from one or both ends of tendons.

Measurement rules


62

PSC type T jack for multistrands tendon


63

Multistrand system


64

PRESTRESSED CONCRETE WORK F.35 IN-SITU CONCRETE MEMBERS

In-situ concrete member shall be given in accordance with

clauses F.1-7.

Members not cast in a continuous length shall be so described stating the number and average length of separately cast section.

Construction joints between section shall be enumerated -NO

Measurement rules


65

Construction joint


66

PRESTRESSED CONCRETE WORK F.36 REINFORCEMENT TO IN-SITU CONCRETE MEMBERS

Reinforcement shall be given in accordance with clauses F.8-9.

Measurement rules


67

PRESTRESSED CONCRETE WORK F.37 FORMWORK TO IN-SITU CONCRETE MEMBERS

Formwork shall be given in accordance with clauses F.10-16

subject to the following ;

a) Additional requirement for supporting formwork shall be described.

b)Formwork to pre-tensioned and post-tensioned work shall each be so described.

c)Temporary restraints required for tensioning of items for formwork.

Measurement rules


68

PRESTRESSED CONCRETE WORK F.37 FORMWORK TO IN-SITU CONCRETE MEMBERS

Formwork for ‘anchorage pockets’ shall be enumerated - NO

(stating the size and shape)

Formwork for temporary construction joints shall be enumerated -NO (stating the section profile of the abutting units)

Measurement rules


69

Anchorage pockets


70

Construction joint


71

PRESTRESSED CONCRETE WORK

F.38 PRECAST CONCRETE UNITS

Precast concrete generally shall be given in accordance with clauses F.17.

Precast concrete units shall be given in accordance with clauses F.21 and F.23.

Measurement rules


72

Pre-cast construction system


73

Pre-cast components


74

PRECAST CONCRETE F.17 GENERALLY

Precast unit including floors shall be given under an appropriate

heading and shall unless otherwise required be enumerated. NO

Measurement rules


75


Particular of the following shall be given ; a. Mix or strength requirements of the concrete. b. Kind, quality and size of reinforcement. c. Nature and extent of surface finish. d. Jointing and bedding materials. e. Method of fixing.

Measurement rules


76


• Formwork or mould for precast units shall be deemed to be

included with the item. • Work required to be designed by the contractor shall be given in

accordance with clauses F.41-45. • Prestressed precast units shall be given in accordance with

clauses F.34-40.

Measurement rules


77

PRECAST CONCRETE

F.21 STANDARD OR PURPOSE-MADE UNITS

The catalogue or other reference number of standard or stock

patterns units shall be given.

Except in the case of items which can be adequately described,

the description of each purpose-made unit shall be

accompanied by drawn information in accordance with clauses

A.5 showing the size and shape of the unit.

Measurement rules


78

PRECAST CONCRETE F.23 TEMPORARY SUPPORTS

Where the design of precast units requires temporary support

after placing in position detail of the requirements shall be given in the description and the condition for the removal of the support stated.

Measurement rules


79

PRESTRESSED CONCRETE WORK F.38 PRECAST CONCRETE UNITS

Precast units shall be classified as follows:

a) Pre-tensioned.

b) Post-tensioned before erection.

c) Post-tensioned after erection. Self-supporting before and after tensioning.

d) Post-tensioning after erection. Self-supporting only after tensioning.

Measurement rules


80

Hollow slab pre-cast construction


81

Pre-cast window unit system


82

PRESTRESSED CONCRETE WORK F.38 PRECAST CONCRETE UNITS

Item description for precast concrete members which are

assembled from sections cast separately shall state whether the sections are assembled before or after erection.

Construction joint between adjacent units shall be enumerated.

Temporary supports for precast units are self-supporting only after tensioning shall be enumerated stating the area of support required and its height where this exceeds 3.50m.

Measurement rules


83

Typical pre-cast beam and floor deck section


84

Construction joint


85


F.39 DUCTS, GROOVES AND POCKETS

Ducts and grooves for post-tensioned prestressing tendons

shall be given in metres (M) stating the number and size.

Particular of the following shall be given: sleeves or sheathing,

temporary supports & mix of grout.

Measurement rules


86

Grouting duct and vent


Vent tube

Steel duct

87


F.39 DUCTS, GROOVES AND POCKETS

Ducts and grooves over 6.00m long shall be so described

stating the length in stages of 3.00m.

Curved ducts shall be described separately.

Measurement rules


88

89


F39.3 DUCTS, GROOVES AND POCKETS- VENTS

• Vents shall be enumerated. NO

Measurement rules


90

Grouting vent


91


F.39.4 FILLING OF ANCHORAGE POCKETS

Filling of anchorage pockets shall be enumerated (NO) stating

the finish of any exposed surface.

Measurement rules


92

Filling of anchorage pockets shall be enumerated (NO)

93


F.40 PRESTRESSED TENDONS

Prestressed tendons shall be enumerated (NO) stating their length, number of wires, ultimate strength and size of wires, type of core and sheathing.

The lengths of pre-tensioned tendons shall be measured to the surfaces of the concrete members.

Description shall state whether tendons are pre-tensioned or post-tensioned members.

Measurement rules


94

Pre-stressed tendons shall be enumerated (NO)

Measurement rules


95

PRESTRESSED CONCRETE WORK F.40.2 ANCHORAGES

Anchorages shall be enumerated (NO) stating their components

Measurement rules


96

Measurement rules

PRE-CAST & PRE-STRESSED CONCRETE Anchorages shall be enumerated (NO)

97

Multistrand system

ANCHORAGE

98

SCD seven strand anchorages

ANCHORAGE

99

PSC monostrand anchorage

ANCHORAGE


Taking off list

101

Taking off list


1 General Item

2 Precast Concrete System : beam, floor, etc No

3 Reinforcement (insitu) m3

4 Formwork for anchorage pocket No

5 Ducting M

6 Vents No

7 Tendons No

8 Anchorages No

9 Filling to anchorage pockets No

10 Construction joint No

11 Temporary support No


Heading and description

103

Description Unit

Precast Concrete Beam

18000 mm long pre-cast beam, Grade 45 with approved type of

reinforcement to engineer’s details with minimum 23 days

concrete works cube strength shall be 50N/mm3 minimum cube

strength at transfer shall be 40N/mm3 including 7-wire super

strands with low relaxation in accordance with ASTMA4160 – 82

per strands

No


PRE-CAST CONCRETE BEAM

104

Description Unit

Ducts and Groove

____ mm thick _____ mm diameter metal sheeting

including temporary supports required, filling in with

cement and sand grouting (1:3) in the formation of the

curved duct exceeding 3.00m but not exceeding 6.00m.

m


DUCTS AND GROOVE

105

Description Unit

Tendons

___ mm long tendons cable conduit of 12 strands per

cable, each strands consist of 7-wires super low

relaxation, ___ mm diameter stressed with minimum of

188 kN per strand.

No


TENDONS

106

Description Unit

Anchorages

Monostrand anchorage including wedges, forge steel

anchorage block with 12 Nos of holes for strand, bearing

plate cast into end of member including socket for steel

duct.

No


TENDONS

107

Description Unit

Filling to Anchorage Pockets

Filling into stressing and anchorage pockets with extreme

size mm x mm including finished with emulsion

paint on all exposed surfaces.

No


FILLING TO ANCHORAGE POCKETS

108

CADANGAN MEMBINA PERSIMPANGAN BERTINGKAT GELANG PATAH DI LALUAN FT001,JOHOR BAHRU.

ITEM DESCRIPTION QTY UNIT RATE AMOUNT

10.4 PRECAST PRESTRESSED

BEAMS AND ANCILLARIES

Excute the proposed works

in accordance with the specification and

as shown in the Drawings.

10.4.1 16.85m long Prestressed

Pretension 'M' beams to site inclusive

of all materials, labour, prestressing,

grouting,lifting, transporting. 56.00 nos 4,800.00 4,800.00

10.4.2 Launch and placing in position 16.85m

long Prestressed Pretension 'M' beams 56.00 nos 330.00 18,480.00

10.4.3 Install 32mm diameter mild

galvanised Dowel Bars,600mm long

with rubber dowel caps as to detail. 12.00 nos 50.00 600.00

10.4.4 Provide 400 X 280 X 59mm thick

laminated elastomeric bearings and

epoxy bedding as to detail. 112.00 nos 145.00 16,240.00

10.4.5 Allow for peliminary tests on

350x200x475mm thick laminated

elastomeric bearings at Rubber Research

Institute of malaysia as specified. 4.00 nos 800.00 3,200.00

TOTAL FOR BILL NO. 10 38,520.00

109

Example of Bill of Quantities



Case study of foot bridge construction

CASE STUDY

PROJECT

CONSTRUCTION OF

FOOT BRIDGE

Fakulti Alam Bina

112

Type of Bridge : Pre-stressed Conrete Bridge Overall Length : 22000 metres PRE STRESSING BEAM PARTICULARS 1. No. of Cables Per Beam = 7 nos ( 4 types) 2. Diameter of Strands = 0.5 inch 3. Nos of Strand Per Cable = 7 nos 4. Length of Cables B/w Bearing = Varies(19700-21775) 5. Tension in Cable at Transfer = 82 tonne 6. Gauge Length = Varies(20150-22225) 7. Weight of Beam = 22.35 tonne 8. Concrete Per Beam = 9 m3

General project data


113

Elevation drawing


114

Section drawing at support


115

Section drawing of pre-stressed beam


116

Taking off list


1 Notes To Contractor

2 Pre Cast Concrete Beam No

3 Ducts & Grooves M

4 Filling to anchorage pocket No

5 Tendons No

6 Grouting Vent To Anchorage No

7 Anchorages No

117

Description Unit

Precast Prestressed Concrete Beam

Preambles

The prestressed precast concrete beam shall be post tensioned after erection

(self supporting before and after tensioning) at 4 m height after casting. Post

tensioned beam including al moulds, finished with painting on all exposed

surfaces including 3 nos steel ducting size 65mm diameter with high tensile

reinforcement hoisting and fixing in position. Prestressing of all cables of beam

consist of 3 nos cable including 12 strands of 7 wire strand class 2 relaxation 12.9

mm diameter for each cable which the ultimate tensile strength at 184 KN per

strand. All cable is post tensioned from one end and stressing in 2 stages, which

is in the first stage, tendon strength is 828 KN, 1656 KN in second stage where is

cable A and B is stressed from left side which cable C stressed from right side

using monostrand anchorage with all cable cast iron and bearing plate cast into

end of members after the stressing was done and fill all ducting withgrout and cut

all cable excess end of anchor with vibratedreinforced concrete grade 45.


PREAMBLES

Description Unit Qty Note


22000m length post tensioned beam, minimum concrete

strenght 45 N/mm3 transfer period and minimum concrete

strenght 50 N/mm3 in 28 days, including 12.7 mm

diameter 7 wire super low relaxation in accordance with

ASTM A4160 - 82 per strand. Each tension stages would

be carried out to 4 strands simultaneously at 2

prestressing stages to total of 138 KN per strand. All

prestressing work shall including testing of each strand

and to form lifting hole and reinforcement all wire end are

cut and holes to be grouted with approved material. All

recesses are to be covered with concrete and make

goods.

No

2

F.34.1- Concrete

member shall be

classified as

prestressed concrete

work where a stress

is artificially induced

in the concrete by

means of tendons

tensioned applied

before working loads

are applied


PRE-STRESSED CONCRETE BEAM



Duct and grooves

M.S ducts and vents for grouting cable positioned at

500 m centres average 110 m including grout mix,

grouting process and make good at access grout

material

M

6

F.39.1 - Ducts and

Grooves for post-

tensioned prestressing

tendons shall be given

in metres stating the

number and size.

Particulars of the

following shall be given

: (a-c)


DUCT AND GROOVES # 1



Duct and grooves

5 mm thick 65 mm diameter flexible mild steel ducting,

including PVC sheating, cement grout and grooves for

tendons each average size 100 mm diameter in 5.0

numbers not exceeding 6.00 length

Ditto, 6.00 - 9.00 m length



M

M

6

3

F.39.1 - Ducts and

Grooves for post-

tensioned

prestressing tendons

shall be given in

metres stating the

number and size.

Particulars of the

following shall be

given : (a-c)


DUCT AND GROOVES # 2



Tendons

3 nos of 20.30 tendon consist of 12 nos of strands and

each strand consist of 7 wire superstrand class 2

relaxation 12.9 diameter and ultimate tensile strength at

184 KN per strand

No

6

F.40.1- Prestressed

tendons shall be

enumerated stating

their length, number

of wires, ultimate

strenght and size of

wires, type of

sheeting


TENDONS



Tendons

Post tension tendons at a length of 19.70 m with

minimum 127mm diameter 7 wire super low relaxation

strands with a minimum UTS of 125 psi per strand

Ditto, at a length of 19.71m, ditto, 124 psi per strand

Ditto, at a length of 21.78m, ditto, 133 psi per strand

No

6

F.40.1- Prestressed

tendons shall be

enumerated stating

their length, number

of wires, ultimate

strenght and size of

wires, type of

sheeting


TENDONS



Filling anchorage pocket

Filling into stressing and anchorage pocket to level of

beam ends with approved concrete grout strength

No

6

F.39.4 - Filling of

anchorage pockets

shall be enumerated

stating the finish of

any exposed surface


FILLING ANCHORAGE POCKETS



Vent

Forming 250 mm diameter vent at 5 m centres at side of

the beam including finished on every exposed upon

completion

No

6

F39.3 - Vents shall

be enumerated.


VENTS



Anchorage

Anchorage of both ends of the beam according to

manufactures instructions

No

6

F.40.2 - Anchorage

shall be enumerated

stating their

components


ANCHORAGE


Studio work

STUDIO WORK

PROJECT

MEMBINA LEBUHRAYA PESISIR PANTAI

DARI JOHOR BAHRU KE NUSAJAYA

FOR

ISKANDAR REGIONAL DEVELOPMENT

AUTHORITY (IRDA)

Fakulti Alam Bina

84102199 Construction Measurement III Week 3 Precast Pre Stressed Concrete

Documents

fakulti alam

ultimate tensile

stressed concreteprecast

smm2 measurement

prestressed

bearing plate

situ concrete

posttensioned