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“Signature Bridge”

Wazirabad Bridge Project

in

SUMMER TRAINING

Department of Civil Engineering

Indian Institute of Technology Delhi

Hauz Khas, New Delhi- 110016

Submitted by

Amit Kumar 2011CE10327

e-mail:iamkumaramit@yahoo.com

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Acknowledgements

I would like to express my special gratitude to my training supervisor at DTTDC

(Delhi Tourism & Transport Development Project), Mr. Priyank Mittal

(Superintending Engineer, DTTDC) whose support and direction immensely

helped in the smooth progression of the internship. He took active interest in

explaining me the concepts and was available for clarification at all junctures.

I would also extend my gratitude towards, Mr. YD Sharma who was the chief

engineer at the Casting Yard. He was always available for guidance. Also, I would

like to thank Mr. Rajesh Singh and Mr. PK Singh who were the chief engineers at

the Western Approach and the Eastern Approach respectively and were very

helpful in explaining the ongoing work at these sites.

Also, I would like to acknowledge the great support extended by Dr. Sashi Mathur,

I.I.T. Delhi who supervised and guided me during the internship.

I would also like to thank my fellow interns for their support during the internship.

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This is to certify that the report submitted by Amit Kumar describes the work carried

by him in the summer training under the overall supervision of Mr. Priyank Mittal

at the Signature Bridge, Wazirabad Bridge Project.

Signature of Student

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Table of Content:

1. Introduction

2. Western Approach

2.1 Erection of Precast segments

2.2 Crash Barrier

2.3 Pre Stressing

2.3.1 Components used in pre-stressing

2.3.2 Methodology

2.3.3 Grouting

3. Eastern Approach

3.1 Components:

3.2 Well foundation:

3.2.1 Components of well foundation:

3.2.2 Well Sinking:

3.2.3 Inspection of well foundation:

3.3 Culvert:

4. Casting Yard:

4.1 Concrete Mix design:

4.1.1 Ingredients

4.2 Casting of structural elements:

4.3 Self compacting concrete:

4.4 QC (quality control) lab:

5. Health and Safety:

6. Conclusion:

7. References

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1. Introduction

‘Signature bridge’ project is a landmark construction project of DTTDC (Delhi

Tourism & Transport Development Project) wherein a cable-stayed bridge is being

constructed across the Yamuna River at Wazirabad. The ambitious project will

connect North Delhi with East Delhi by linking NH -1 near existing T- point at

Wazirabad on western bank and Bund road at Khajuri Khas on Eastern Bank of

Yamuna River. The population explosion in the region has culminated into a heavy

demand for better infrastructural facilities leading to traffic congestion and delays.

Another factor that led to the sanction of the project was the absence of a modern

landmark structure in the city leading to lesser tourists.

With a length of about 575 meters and a height of 175 meters the proposed Signature

Bridge would have a bow-shaped pylon in the middle making it a promising tourist

attraction in Delhi. Two high towers will be there to provide double cable support in

the inner periphery of the carriageway. Plans are also afoot to construct a pedestrian

sub-way at an approximate cost of Rs 29 lakh.

Fig 1: Signature Bridge

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Equipped with eight lanes, this engineering masterpiece will have 1.2 meter wide

central verge, space for anchoring cables, maintenance walkway and crash barrier

on either side of the central verge. The deck will be composite (steel and concrete)

while pylon will be in steel.

Schlaich Bergermann and Partner of Germany have been appointed as consultants

for designing the bridge while M/s Systra SA of France has been appointed as Proof

Consultant.

Construction of bridge will be in phase-I while in phase-II, area around the bridge

will be developed, for example cleaning of Yamuna River for nearly 1 km

downstream of Wazirabad barrage, creation of water bodies for tourists, construction

of walkways from Wazirabad to Majnu ka Tilla.

Fig 2: Plan of signature Bridge

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Figure 3: Perspective View of the bridge

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1.1 Project brief

PROJECT NAME: Signature Bridge (Yamuna Bridge at Wazirabad)

COST OF PROJECT: Rs 631.81 cr (revised) [original was Rs460 cr]

TOTAL LENGTH: 575m (8 lanes)

PYLON HEIGHT: 151.14m (5400 ton)

FOUNDATIONS: 6 open and 18 well foundations

ADDITIONAL WORK: Eastern and Western approaches

COMBINED COST: Rs 1,131 cr partially funded by JNNURM (Rs 380.6

cr)

NATURE OF CONTRACT: Construction of bridge & its approaches over

Yamuna River at Wazirabad Delhi SH-main bridge (cable stayed)

REINFORCED CONCRETE: 45,000 m3

REINFORCEMENT: 4,700 tons

DATE OF COMMENCEMENT: June 2008

TARGET DATE OF COMPLETION: Dec 2013

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1.2 Design Consultants:

Bridge Approaches

Preliminary Design M/s Stup Consultants Pvt M/s Stup Consultants Pvt

Ltd Ltd

Main Design Consultant M/s Schlaich M/s Tandon Consultants

Bergermann & Patners, Pvt Ltd (TCPL)

Germany

Associates to Main M/s Construma M/s L R Kadiyali

Consultant Consultancy Pvt Ltd M/s Archom

(CCPL)

Proof Consultant M/s7 Systra, France M/s Construma

Consultancy Pvt Ltd

(CCPL)

Associates to Proof M/s Tandon Consultants -

Consultant Pvt Ltd (TCPL)

Soil investigation M/s Cengers Pvt Ltd

Features of bridge:

The Bridge Length is 575m and an additional 100m West extension.

It has 2 x 4 Lanes along with a Service Track.

The carriageway has a width of 14 m on either side with a central verge of 1.2m

and service track of 2.5m on either side.

The bridge has a cable stayed deck with front and back stays.

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Pylon:

The pylon is a bow shaped, eccentric steel structure with height of 154 m and main

span of 251m. The secondary spans which are 9 in number are of 36m.

15 Stay Cables are used on the front side and 4 back stays on the other side

Deck:

The deck is RCC Precast / In-situ Steel- Concrete Composite with plate girders up

to 2m depth and thickness of 250 to 700mm

Foundations:

Figure 4: Foundations of the Piers

Two types of foundations were used:

1. Open Foundations with Sheet Pile Coffer (9 nos)

Pylon Foundation:

Diameter -22m, Thickness - 4m

Depth of Foundation : 19m below River Bed

Rectangular Coffer : 28x 28m size

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2. Well Foundations (Rock Anchored) (18 nos)

Well Dia : Varying from 8 to 17.5m at Cutting Edge & 8 to 15.75m at Top

Approaches:

Contract Amount : Rs. 348.9 Cr.

Commencement of Work : June 2008

Duration of Work : 42 Months

Schedule Completion : December 2011

Target Completion : June 2013

Contractor : Gammon India Ltd.

Geometric features of approaches:

No. of Lanes on Main Flyovers : 3+3 Lanes

No. of Lanes on Loops/Ramps : 2 Lane

No. of Lanes on Lower level loops : 2 Lanes + Cycle trek

Width of Carriage Way

Main Flyover Carriageway : 11+11m

Central Verge : 1.2m

Loops/Ramps Carriageway : 9.0m

Cycle Trek : 2.5m

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2. Western Approach

It includes construction of flyovers, loops and ramps at the proposed intersection of

bridge with Road no.45 and existing intersection at Timarpur, Nehru Vihar and

Wazirabad.

Figure 5: Western Approach

Components:

1.8 km long main flyover along ring road integrating 3 intersections.

8 loops & ramps for right and left turning traffic, connecting to the main

bridge.

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2.1 Erection of Precast segments The precast segments of the bridge were constructed in the casting yard and then

erected at the site either using launching girder or under slung support systems as

shown in the figure below:

Fig 6: Erection of Precast Segments Using Launching Girder

Fig 7: Erection of Precast Segments using Under-Slung Support System

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2.2 Crash Barrier:

Fig 8: Crash Barrier

Crash barrier is designed to restrain vehicles from crashing off the side of a bridge

and falling onto the roadway, river or railroad below. It is usually higher than

roadside barrier, to prevent trucks, buses.

2.3 Pre Stressing

Pre-stressed concrete is a method for overcoming concrete's natural weakness in

tension. It can be used to produce beams, floors or bridges with a longer span than

is practical with ordinary reinforced concrete. Pre-stressing of concrete is the

application of a compressive force to concrete members and may be achieved by

either pre-tensioning high tensile steel strands before the concrete has set, or by post-

tensioning the strands after the concrete has set. The common terms used in pre-

tensioning are as follows:

a) Tendon: A stretched element used in a concrete member of structure to impart

pre-stress to the concrete. Generally, high tensile steel wires, bars, cables or strands

are used as tendons.

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b) Anchorage: A device generally used to enable the tendon to impart and maintain

pre-stress in concrete.

c) Pre-tensioning: Pre-tensioning is the application, before casting, of a tensile

force to high tensile steel tendons around which the concrete is to be cast. When

the placed concrete has developed sufficient compressive strength a compressive

force is imparted to it by releasing the tendons, so that the concrete member is in a

permanent state of pre-stress.

d) Post-tensioning: Post-tensioning is the application of a compressive force to the

concrete at some point in time after casting. When the concrete has gained strength

a state of pre-stress is induced by tensioning steel tendons passed through ducts cast

into the concrete, and locking the stressed tendons with mechanical anchors. The

tendons are then normally grouted in place.

e) Bonded Pre-stressed Concrete: Concrete in which pressure is introduced to

concrete through a bond between the cables and surrounding concrete. Pre-tensioned

members belong to this group.

f) Non Bonded Pre-stressed Concrete: Concrete in which pre-stress is introduced to

concrete through anchorage devices and tendons or cables vare not bounded to

concrete.

2.3.1 Components used in pre-stressing:

HT Stands

HDPE Sheathing

Guide (transfers pre-stressing force from bearing plate to the concrete)

Bearing Plate

Grips and Circlips

Mono Jack SC-2

2.3.2 Methodology

The concrete is cast around a plastic curved duct, to follow the area where otherwise

tension would occur in the concrete element. A set of tendons are fished through the

duct and the concrete is poured. Once the concrete has hardened, the tendons are

tensioned by hydraulic jacks that push against the concrete member itself. When the

tendons have stretched sufficiently, according to the design specifications (see

Hooke's law), they are wedged in position and maintain tension after the jacks are

removed, transferring pressure to the concrete. The duct is then grouted to protect

the tendons from corrosion. This method is commonly used to create monolithic

slabs for house construction in locations where expansive soils (such as adobe clay)

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create problems for the typical perimeter foundation. All stresses from seasonal

expansion and contraction of the underlying soil are taken into the entire tensioned

slab, which supports the building without significant flexure.

After Stressing of segments water treatment and grouting is done. Water treatment

is done to check the presence of air voids inside the segments which may corrode

the HYSD bars used for stressing. In grouting, water & cement are mixed in ratio

0.4:1.

2.3.3 Grouting

The purpose of grouting the cable is to provide permanent protection to the post

tensioned steel against corrosion and develop bond between pre-stressing steel and

surrounding concrete. The grout ensures encasement of steel for corrosion protection

and fills the duct space to prevent water/air passage.

The materials used here are OPC-43 grade cement, clean water, FORSOC

Admixture.

Checks done in grouting:

• Water temp. maintained below 25 degrees Celsius • Density of grout • Pressure of grout pump maintained at 5 Kg/cm2

Figure 9: Ongoing Activities at Western Approach

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3. Eastern Approach

Figure 10: Eastern Approach

3.1 Components:

A 1.8 km Long and 10 to 12m High Embankment.

Ground Level Rotary on High Embankment (120m Diameter)

A 850m long Flyover at Khajuri Khas Intersection.

Guide Bunds, Launching Apron & Slope Protection Works.

3.2 Well foundation:

Well Foundation have their origin in India. Well Foundation have been used in India

for hundreds of years for providing deep foundation below the water level for

Monuments.

A well foundation is similar to open cassion. Well Foundations can be constructed

on the dry bed or after making a sand island. At locations where the depth of water

is greater than 5m to 6m and the velocity of water is high, wells can be fabricated on

the river bank.

It is suitable for deep water where it is difficult to carry construction equipment

suitable for river bed, alluvial soil which mainly consists of sandy.

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Well cap

Slab

Water fill

Top plug (500 mm)

Steining wall

Sand fill

Bottom plug Cutting edge

Top view of well B.M-2

B.M-1 B.M-3

800 mm

800 mm B.M-4

5900 mm

7500 mm

Figure 11: Well Foundation

4 bench marks are provided on every quarter of well so as to notice tilting and

shifting of the well.

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3.2.1 Components of well foundation:

Cutting Edge:

The lower most portion of the well curb is the cutting edge

It cuts into the soil during sinking. It is fabricated in 5 or 6 pieces and are numbered

for ease in assembly. Then these cutting edges are assembled and placed on a

levelled platform and are compacted uniformly to preclude possibility of settlement

during curb concreting.

Well Curb:

The lower wedge-shaped portion of well staining is called the well curb

It facilitates the process of sinking. Curb casting is done in a single stage. Casting

involves reinforcement fixing where steel bars are cut and bent as per the approved

bar bending schedule (BBS); shuttering fixing, concreting and de-shuttering.

Steining Wall:

It is the main body of well which transfers load to the subsoil.

Acts as a cofferdam during sinking and provides weight for the sinking. The

procedure for reinforcement fixing, shuttering fixing, concreting and de-shuttering

is the same as in well curb.

Bottom Plug:

After the well is sunk to the required depth, the base of well is plugged with concrete.

This is called bottom plug. It transmits the load to the subsoil. On completion of

sinking up to the founding level, various parameters like final tilt & shift, strata

obtained in bore log, rock level below the cutting edge, concrete quantity for bottom

plug shall be checked. The bottom plug shall be provided in all wells and the top

shall be kept not lower than 300 mm in the centre above the top of the curb. Height

of sump should be sufficient (about 150 mm) to permit easy flow of concrete through

tremie to fill up all cavities. Concrete shall be laid in one continuous operation till

the dredge hole is filled to the required height. For under water concrete, the concrete

shall be placed by tremie under still water condition and the cement content of the

mix be increased by 10 percent.

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Sand Filling:

Sand filling shall commence after a period of 14 days of laying of bottom plug. Also,

the height of the bottom plug shall be verified before starting sand filling. Sand shall

be clean and free from earth, clay clods, roots, boulders, shingles, etc. and shall be

compacted as directed. Sand filling shall be carried out up to the level shown on the

drawing or as directed by the Engineer

Dredge Hole:

The well is sunk by excavating soil from within the well. The hole formed due to the

excavation of soil is called the dredge hole. It is later filled with sand. This sand

filling helps in distributing the load of superstructure to the bottom plug.

Top Plug:

It is a concrete plug covering the sand filling usually constructed on top. It provides

contact between the well cap and sand filling and helps in transferring the load

through the sand filling. A 300 mm. thick plug of cement concrete shall be provided

over the filling

Well Cap:

It is a RCC slab laid on top of the wall staining and is usually cast monolithically

with staining. Transmit the load of superstructure to the staining. A reinforced

cement concrete well cap will be provided over the top of the steining in

accordance with the drawing. Concreting shall be carried out in dry condition. A

properly designed false steining may be provided where possible to ensure that the

well cap is laid in dry condition.

3.2.2 Well Sinking:

It occurs in two parts- first due to self-weight (till about 10m) and then through the

jack down (about 38-40m). Jackdown sinking is basically transferring the forces

exerted by the hydraulic jacks on the earth anchors to the heavy duty pressurization

girders resting on the steining top through stools. The earth anchor pairs are placed

such that two girders systems, both crossing the well sides, can be positioned, with

hydraulic jacks at the ends of the girder, located such that they are directly above

the center of the earth anchor pair. For loading jacks we use anchorage wire HYSD

bars Fe 500.

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3.2.3 Inspection of well foundation:

Tilt is the inclination of the well from the vertical while sink is the horizontal

displacement of the center of the well at the founding level from its theoretical

position. Tilt occurs due to uneven loading and the major reason for shifting of well

is Sand blow. Sand blows beneath the well due to increase in load on one side. The

values of tilt and sink are used in inspection of well. The tilt of any well shall not

exceed 1 (horizontal) in 80 (vertical), and the shift at the well base shall not be more

than 150 mm in any resultant direction.

Methods adopted for preventing shifting and tilting of well include Eccentric

dredging, eccentric loading, Pull to well, and Push to well.

3.3 Culvert:

A culvert is a drain or pipe that allows water to flow under a road, railroad, trail, or

similar obstruction. Culverts differ from bridges mainly in size and construction.

Culverts are generally smaller than bridges, ranging from 0.3-metre (1 ft) pipes to

larger reinforced concrete structures.

In signature bridge project, eastern approach has two types of culverts: 2 - cell and

4 – cell

Figure 12: Ongoing Activities at Eastern Approach

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4. Casting Yard:

Figure 13: Casting Yard

4.1 Concrete Mix design:

The concrete used in the project were:

Plain Cement Concrete: M10, M15

High Performance Concrete: Using slag cement (M35, M45, M50) or

using OPC (M25, M35, M45, M50, M60).

Self-Compacting Concrete: M60, M65

Pavement Quality Concrete: M35, M40

4.1.1 Ingredients

1. Cement: two type of cements are used OPC and Slag cement.

2. Water: Treated water from R.O plant is used to avoid degradation in quality

of reinforcement by corrosion by fluorides and various salts present in bore-

well water.

3. Aggregates:

Coarse aggregates - 10 mm & 20 mm.

Fine aggregates

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4. Admixtures

Mineral Admixture Used: Silica Fume, Flyash

Chemical Admixture Used: Naphta Based, Poly Caboxyl Ether(PCE)

Based, VMA

Yard consists of two silos for fly ash and silica fume.

4.2 Casting of structural elements:

In precast technology the segments are pre casted in casting yard far from actual site.

After casting they are transported to the site for erection. In the signature bridge, the

casting of many structural elements were done in the casting yard which was Main

advantage of pre-casting are that it saves time, it prevents hindrance in normal life

of people living near project site and it is more safe.

Signature bridge pre-casted materials are –

a) Segments

b) Ribs

c) Kerb stone

d) Facia panel of crash barrier

4.3 Self compacting concrete:

Self-consolidating concrete or self-compacting concrete is characterized by a low

yield, high deformability, and moderate viscosity necessary to ensure uniform

suspension of solid particles during transportation, placement (without external

compaction), and thereafter until the concrete sets.

Such concrete can be used for casting heavily reinforced sections, places where there

can be no access to vibrators for compaction and in complex shapes of formwork

which may otherwise be impossible to cast, giving a far superior surface than

conventional concrete. In our case SCC is used for casting of piers.

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4.4 QC (quality control ) lab:

The various tests are performed here for concrete ingredients.

Tests performed for

cement

Tests performed for aggregates

Fineness test

Sieve test

Settling test

Sieve analysis

Crushing value test

Impact value test

10 % fines value test

Silt content

Specific gravity

Flakiness & elongation test

The tests performed here on concrete are:

Non-self compacting concrete Self compacting concrete Slump test

Settling time test – initial settling

time , final settling time

Crushing value test (performed

on cubes)

V funnel test

L- box test

flow test

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5. Health and Safety:

All staff including officers visiting shall wear safety gear such as helmets and

safety shoes. Welding goggles and hand gloves are also provided to welders /

cutters.

To avoid contact of grout mix gloves, eye/face protection and dust masks shall

be provided to the workers at grouting operation. In case the grout in contact

with skin it shall be washed with clean water. In case of contact with eyes it

shall be rinsed with plenty of water and medical attention shall be sought

immediately.

Use proper sling while lowering the bracket, beam & Struts in the excavated

area by crane.

Care shall be taken for lowering the Bracket, wailer & struts at the lower level

as not to touch the assembly at the upper level.

Proper stage wise ladder shall be provided for movement of workers in the

excavated area.

All the workers working in the area shall be equipped with PPE such as

helmets and safety shoes & safety goggles.

Periodic health check-up will be arranged for workers. Necessary caution /

signboards shall be displayed.

First aid box shall be kept at site.

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6. Conclusion:

The summer training period exposed us to almost all practical aspects of civil

engineering, especially construction of foundations, erection of structural elements,

reinforcement of concrete, many tests to check strength and durability of structural

elements, etc. Besides civil engineering we got opportunity to learn about

management of such a big project and steps taken to prevent cost overrun and delays.

Handling such a project requires a great dedicated team effort .This training provided

us the practical knowledge which cannot be explained in the institute campus nor in

any laboratory.

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7. References

“The Signature Bridge”, Presentation given to MD, DTTDC

“Steel Structures and Metal Buildings”, Vol.1 Issue-4, February 2011.

Wikipedia: Foundation Engineering

http://en.wikipedia.org/wiki/Foundation_(engineering)

“Signature Bridge delayed, LG slams tourism agency”, Times Of India.