Construction of Segmental Concrete Bridge

8/12/2019 Construction of Segmental Concrete Bridge

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METHOD OF CONSTRUCTION OF

SEGMENTAL CONCRETE BRIDGE

By ,

P P AMBEDKAR


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Objective Of Dissertation work

Construction of segmental bridge involves use of different machineries

and requires huge amount of skilled manpower. Hence the intention of

dissertation is to study the Methods & techniques used in Construction

of Segmental Bridge by Under Slung Methodwhich consist of

following activities.

1.Construction of Sub-structure

2. Construction of super-structure


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Development of precast segmental bridge construction

First segmental bridge

Second segmental bridge

Segmental bridges in India


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What is segmental construction

Pier

PC segments

Prestressing cables


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Method of construction of segmental bridge

1.Cast-in-Place Segmental Construction (Balance Cantilever method)

Bridge across the Lahn River in Germany


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2. Precast Segmental Construction

Flyover at Agriculture College Pune


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General design consideration

Principal Dimension of Segment

W = Top Slab width

D = Construction depth

B = Bottom slab width

L = Segment length


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Construction of substructure

Cast-in-situ Pile

Detailed breakdown of activities is mentioned below

1. Setting Out

2. Removal of Overburden3. Driving Permanent Liner

4. Boring / Chiseling

5. Reinforcement Cage Lowering

6. Concreting


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1. Setting Out


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2. Removal of overburden

3. Driving permanent liner

Tripod

Driving cap

Drivingmonkey

Liner


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4. Boring/ Chiseling

BAILER

CHISEL


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BailerExcavated mud

Removing of excavated material with help of bailer


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5. Reinforcement cage lowering

6.Concreting

Chute

Funnel

Tremie pipe


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Major Equipment Required

1) F 35d/d winch - 4 no2) Pile driving tools & accessories - 4 set

3) Tripod - 4 set

4) Generator 70 KVA - 2 no

5) Welding machine - 2 no

6) Concreting equipments - 2 set

7) Batching Plant - 1 no


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TIME CYCLE

Sr.No. Activity Duration

1 Road breaking/removal of top overburden/

Identification of utility services.

2 days

2 Positioning tripod / winch 2 hours

3 Survey & setting out 2 hours

4 Permanent liner driving/ boring 20 hours

5 Chiseling(6m @ 0.1m/hour) 60 hours

6 Cage lowering 2 hours

7 Tremie Pipe lowering/flushing 2 hours

8 Concreting 3 hours9 Removal of tripod/winch 2 hours

Total time for pilling 93 hours

There fore total time for one pile @ 20hours per day

working

4.5 days


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Construction Of Pile Cap

Detailed breakdown of activities is mentioned below

1. Clear area for excavation and marking

2. Exaction up to pile cap bottom level

i. Excavation in soft soil

ii. Chiseling in hard strata

3. Simultaneously chipping of pile

4. Preparation of bed with PCC

5. Cutting and bending and preparation of reinforcement

cage

6. Shuttering for pile cap

7. Concreting


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1. Clear area for excavation and marking

2. Exaction up to pile cap bottom level

i. Excavation in soft soilii. Chiseling in hard strata

3. Chipping of pile

Bottom of

Pile cap Pile chipping by jack

hammer


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4. Preparation of bed with PCC

Bed preparation

for pile cap by

laying PCC


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5. Cutting and bending and preparation of reinforcement

cage

Pile reinforcement

bar

Tying ofreinforcement


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6. Shuttering

7. Concreting of pile cap

Shuttering

Haizen cloth for

curing


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MAJOR EQUIPMENTS REQUIRED

1. JCB Excavator 1 No.

2. Dumper 1 No.

3. Breaker (Jack hammer) 2 Nos.

4. Bar bending and cutting machine 1 No.5. Concrete batching plant 1 No.

6. Transit Mixer 2 Nos.

7. Needle vibrators (60 mm) 2 Nos.


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TIME CYCLESr.No. Activity Duration

1 Waiting period for curing of pile 7 Days

2 Clearing area, survey and marking for excavation 2 Hours

3 Excavation in soft soil 12 Hours

4 Chiseling in hard rock 2 Days

5 Cutting and removing liner 4 Hours

6 Chipping piles up to pile cap bottom level PCB) 4 Days

7 Preparation of bed with PCC as leveling course 8 Hours

8 Reinforcement cutting, bending and fabricating cage 1 Day

9 Placing and fixing shuttering 3 Hours

10 Concreting 1 Hour

Total time = 8.5 days


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Construction of Pier

Job breakdown1. Cutting, and bending of reinforcement

2. Preparation of reinforcement cage

3. Casting Pier starter

4. Erection of staging and simultaneously fixing

shutters

5. Concreting of pier

6. De-shuttering and dismantling staging

7. Curing


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1. Cutting, and bending of reinforcement & preparation of

reinforcement cage

2.CastingPierstarter3. Erection of staging and simultaneously fixing shutters

Pier shutter

Staging for supporting pier shutter

& providing working platform at

top for concreting


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4. Concreting of pier

5. Curing

MAJOR EQUIPMENTS REQUIRED

1. HM 101 Crane -1 No

2. Bar bending and cutting machine-1 No.

3. Concrete batching plant -1 No.

4. Transit Mixer - 2 Nos.5. Concrete Pump -1 No.

6. D.G. Set -1 No.

7. Compressor - 2 Nos.

8. Needle vibrators (60 mm) - 2 Nos.


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TIME CYCLE

Sr. no. Activity Duration

1 Cutting and Bending Reinforcement 2 Days

2 Tying and Cage Preparation 1 Day

3 Casting Starter and Curing 2 Hrs.

4 Staging and Simultaneously Shuttering 1 Day

5 Concreting 3 Hrs.

6 Waiting till achieving strength for deshuttering 1 Day

7 Deshuttering 12 Hrs.

8 Curing 28 Days

Total time required excluding curing = 3 days


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CONSTRUCTION OF APPROCHES

Construction of approach involve two major activity that are

as follows:

i) Construction of Abutment wall.

ii) Construction of Wing wall (Retaining wall)


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Types of abutment:

Masonry abutments:

RCC abutments:


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R.C.C Abutments

In this case abutment wall is directly rest over raft /pile foundation.

Whole abutment wall made of rich mix concrete. Abutment wall

construction involves following activity:

1. Cutting, and bending of reinforcement

2. Preparation of reinforcement cage

3. Casting abutment starter

4. Erection of staging and simultaneously fixing

shutters

5. Concreting of abutment.

6. De-shuttering and dismantling staging

7. Curing


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Staging

arrangement

Shuttering

RCC Abutment


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The wings walls are of masonry or RCC masonry, now days wings wall are constructed

with new technique that is Geosynthetic Soil Retaini ng wallin which precast RCC

panel is used. The advantage of this construction system is given below.

1. It requires very limited construction space compared to the conventional wall

systems.

2. The completed structure occupies less space compared to the conventional wallsystems.

3. By using a facing of high rigidity, the stability of the wall system is increased while the

deformation is minimized.

4. The geosynthetic layers are closely spaced so that a wide range of backfill can be

used without affecting performance.

Wing wall


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Component of part of GSR Wall

1.Concrete leveling Pad:

2.Precast concrete facing panels

3.Joint material

4.Geogrids

5.Backfill


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Construction of Superstructure

Construction of Superstructure of segmental bridge involves two

major activities that are as follows:

1) Segment Casting

2) Segment Erection

Different method of segment casting:

1)Long line casting

2)Short line casting


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Long line casting


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Short line casting


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Segment casting involves following activities

1) Base mould preparation

2) Surveying and marking

3)Reinforcement cage leveling

4)Lowering and positioning stopend

5)Placing and fixing inner formwork

6)Concreting and finishing

7)Deshuttering of inner formwork and stopends

8)The segment used for match casting is then placed in the stacking yard and the newlycasted segment is used for next match casting.


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1)Pre-cast Bed Survey and Setting out of moulds as per

the co-ordinates.


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2)Changing/re-fixing of linermaterial where required and

cleaning of beds.

RUBBER LINER

3)Surveying and marking

4)Reinforcement cage lowering:

LIFTING FRAME

REINFORCEMENT CAGE

EOTCRANE


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5)Lowering and positioning stopend:

Turn buckels

False work

Stopend

REINFORCEMENT CAGE


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6. Placing and fixing inner-

formwork:

Inner formwork

7.Concreting and finishing:


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8.Deshuttering INF& Stopend:

9. Lifting and stacking of segments:

MAJOR EQUIPMENTS REQUIRED FOR SEGMENT

CASTING

1) EOT 120T Capacity - 1 No.

2) Welding Machine - 2 No.

3) Gas-cutting Equipment - 2 No.

3) Concreting Equipments - 2 Sets

4) Batching Plant - 1 No.

5) Transit Mixer - 2 No.


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TIME CYCLESr. No. Activity Description Time

Required

in Hrs.

1 Base mold cleaning, rectification of rubber liner and applying

POP

6

2 Survey and marking 1

3 Lowering reinforcement cage 1/2

4 Lowering and aligning stopend with jacks and knuckle bolts 1

5 Placing and fixing inner-formwork 8

6 Concerting and finishing 3

7 Curing till deshuttering stopend 248 Deshuttring stopend 2

9 Curing till deshuttering inner-formwork 46

10 Lifting and stacking segment 1

Total time= 92 Hrs


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Segment Erection

Probably the most significant classification of segmental bridges is bymethod of construction. Although construction methods may be varied as

ingenuity of the designers and the contractor they fall into two basic

categories:

1) Cast-in-Place segmental construction. (Balance Cantilever method)

2) Precast segmental construction.


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Precast segmental construction

1)Segment erection by Crane

2) Segment erection byWinch and Beam


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3)Launching Gantry(Over head method)

4)Segment erection by Under-slung

method


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Segment erection by Under Slung Method

Segment erection involves following activities

1. Survey and Barricading

2. Erection of EOT

3. Fabrication and erection of staging

4. Erect sliding trolley with jack arrangement5. Launch precast segments

6. Temporary pre stressing of segments

7.Permanent pre stressing


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2. Erection of EOT

Rail track alignment

EOT crane of 125 tone

capacity


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3. Fabrication and Erection of Staging

Main girder

Seating girder

Concrete block

Cribs

Bracing


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4. Erect Sliding Trolley with Jack Arrangement

Screw jacks arrangement

with pot bearing

Main girder

Tie box


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Inside temporary prestressing


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8. Bearing Installation


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C S d


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Case Study

NAME OF PROJECT:

PUNE FLYOVER ATUNIVERSITY CIRCLE

& AGRICULTURE COLLAGE.

SITE ADDRESS:

GANESHKHIND ROAD,

UNIVERSITY CIRCLE,

PUNE 411 007

NAME OF CONTRACTOR:

AFCONS INFRASTRUCTURE LIMITED

NAME EMPLOYER:

MAHARASTRA STATE ROAD

DEVELOPMENT CORPORATION

NAME CONSULTANT:

DAR CONSULTANTS (U.K) LTD.

in association with

DAR CONSULTANTS (I) PVT. LTD


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UNIVERSITY CIRCLE JUNCTION:

GENERAL FEATURES OF UNIVERSITY CIRCLE FLYOVER

1) Length = 700 M between abutments

2) Carriageway = Single three lane carriageway

3) Foundation = Bored cast-in situ piles resting on rock

4) Substructure = RCC Piers

5) Superstructure = Segmental, Deck width 12 M


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AGRICULTURE COLLEGE JUNCTION

GENERAL FEATURES OF AGRICULTURE COLLEGE FLYOVER

1) Length = 210 M between abutments

2) Carriageway = Dual two lane carriageway

3) Foundation = Bored cast-in situ piles resting on rock

4) Substructure = RCC Piers

5) Superstructure = Segmental, Deck width 16.4 M


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The pre-casting Yard includes the following:

Casting Bay : For casting deck segments.

Curing Yard : For curing deck segments.

Stacking Yard : For stacking deck segments.

Reinforcement Yard : For fabrication of reinforcement of all structural elements

like pile, pile cap, pier, precast segment, etc.

Casting, Curing & : For casting, curing & stacking of Parapet, Retaining

Stacking Bay wall & Kerbs.

Fabrication workshop: For fabrication of structural steel for shuttering,

supportive elements & temporary works.

Mechanical workshop : For fabrication of tie rod

CLASSIFICATION OF SEGMENTS


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No TypeSegment

widthLocation & Function

1

End Diaphragm (ED) 1.45 ED rest on Abutment. It also has a

downstand that enables it to sit onbearings. It has a wall ... It houses

coupler cones for pre-stressing

cables which are locked here.

2Adjacent to End Diaphragm

(EDA)

2.095It is located adjacent to ED segment.

3 Internal Diaphragm (ID)

2

ID segment rest on all the piers except

expansion piers.

4Standard Segment(SS) 2.725 There are 3 nos. SS in the middle of

every span.

5

Coupling segment stressing

end (CSS)

2.917 CSS segment last segment of

intermediate span which has

stressing

6Coupling segment coupling

end (CSC)

2.917 CSC Segment is starting segment of

next span


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TYPICAL SECTION THROUGH DECK SEGMENT (CS) 16.4M WIDE


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SEGMENT ERECTIONThere are 3 types of spans to be erected i.e.:

Type A-Beginning span of each bridge unit,

Type B-Internal spans,

Type C- End of each unit.

Type A has 13 segments to be erected with an End diaphragm at the start of

the span. And a CSS segment at the end of the span.

Type B Span start with CSC segment & end with CSS segment.

Type C Span start with CSC segment & end with ED segment.


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For erection of 16.4 m wide segment involves following activities


2. Erection of EOT

3. Fabrication and erection of staging

4. Erect sliding trolley with jack arrangement

5. Launch precast segments

6. Temporary pre stressing of segments

7. Permanent pre stressing

MAJOR EQUIPMENTS DEPLOYED


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MAJOR EQUIPMENTS DEPLOYED

1) EOT 60T Capacity - 1 No.

2) EOT 120 T capacity - 1 No.

3) Service crane PH 320 - 2 No

4) JCB Excavator -

2 Nos.

5) Trailer of 40 T capacity - 3 No.

6) Trailer of 100 T capacity - 1 No.

Labour required for segment erection including staging& gluing :

Welder = 01

Grinder = 01

Gas cutter = 01

Skilled labour = 17

Unskilled labour = 10

TOTAL NO. = 30


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Following were the main reasons to delay in the completion of project

Land acquisition problem

Improper matching of segment

Delay in decision making

Labour strike

Delay in approval of drawings from consultant

Delay in diversion of utilities


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CONCLUSION

After studying detail procedure segmental construction that

segmental bridges posses following advantages

Rapid erection of superstructure.

High quality & high strength of concrete can be achieved.

Whenever we need to allow traffic underneath even during

construction.

The structural geometry may be adopted to any horizontal or vertical

curvature or any roadway super-elevation.

Concrete shrinkage & creep substantially reduced.

Segmental construction relatively insensitive to weather condition.

Enhanced durability of bridge.

Segmental bridge reveals following disadvantages


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Segmental bridge reveals following disadvantages

Need for higher level of technology in design

Necessity for a high degree of dimensional control.

The possible solution to the problems discussed in the case

study can be enlisted as follows:

Perfect matching of segment at site can be achieved by considering vertical &

horizontal alignment of bridge profile at the time of segment casting.

Whenever the segments are not matched properly considerable time is lost in

chipping out the segment faces. Hence the segment casting should be done

accurately in accordance with drawings.


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Thank You

Documents

Construction of Segmental Concrete Bridge