Launching of Viaduct

8/2/2019 Launching of Viaduct

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ERECTION OF A VIADUCT

Submitted by

Sushant Anchan 253008

PGP ACMXXV 2011-2013

A Mini-Thesis Submitted In Partial Fulfillment of the Academic

Requirements for the Award of

Post Graduate Programme in Advanced Construction Management

NATIONAL INSTITUTE OF CONSTRUCTION MANAGEMENT

AND RESRARCH, HYDERABAD


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DECLARATION

I declare that the research thesis entitled ERECTION OF A VIADUCT

is a bona-fide research work carried out by me, under the esteemed

guidance of Mr. K.SRINIVAS. The scope of the research has been strictly

confined to the erection procedure of the viaduct only. Further I also

declare that this has not been previously formed the basis of award of any

degree/diploma/associate-ship or other similar degrees/diplomas and has

not been submitted anywhere else.

SUSHANT ANCHAN 253008

Date :

Place : HYDERABAD


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CERTIFICATE

This is to certify that this project work entitled ERECTION OF A

VIADUCT is a record of bona-fide original work done by Mr. Sushant

Anchan, PGP ACM XXV, Roll No. 253008, during the year 2011-2013.

This work is submitted to the Department of Post Graduate Programme

in Advanced Construction Management in partial fulfilment for the

degree of Post Graduate Degree in Advanced Construction

Management.

Date :

Place : HYDERABAD

Guide :

Mr. K . SRINIVAS Mr. K. R. RAMANA

Associate Professor, Dean,

NicmarCISC, NICMAR-CISC,

Hyderabad. Hyderabad.


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ACKNOWLEDGEMENT

Any endeavour can not lead to result unless and until a proper platform is

provided for the same. I would like to express my thanks to the institute for

giving us the opportunity to undertake this project work.

I would also like to express my sincere regards to Prof. K.R. Ramana, Dean,

NICMAR, Hyderabad for his guidance, valuable suggestions and

encouragement throughout the progress of this work.

It also gives me immense pleasure in thanking Prof. B. Ravinder, our

programme coordinator and Prof. K. Srinivas, my project guide, for their

esteemed guidance and outstanding support in finishing this mini-thesis

successfully.

Finally my sincere thanks also goes to the officials of GAMMON INDIA

LIMITED, KMRC Project who have helped my with all the site datas and

required and relevant informations for this project to be completed and without

whose help this work would have been next tp impossible.

Sushant Anchan.


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INDEX

CONTENTS PAGE N0

1. INTRODUCTION TO SEGMENTAL CONSTRUCTION1.1. WHAT IS SEGMENTAL CONSTRUCTION ? 7

1.2. DEVELOPEMENT OF SEGMENTAL CONSTRUCTION

OF BRIDGES 7

2. LITERATURE STUDY2.1. CHESAPEAKE & DELAWARE CANAL BRIDGE,

ST. GEORGES, DELAWARE, USA 11

2.2. LINN COVE VIADUCT, CAROLINA 12

2.3. JOHN T. COLLINSON CSX RAIL BRIDGE,

PENSACOLA, FLORIDA 12

2.4. METROPOLITAN ATLANTA RAPID TRANSIT

AUTHORITY(MARTA) CS360 & CN480, ATLANTA,GEORGIA 13

2.5. WASHINGTON METRO AREA TRANSIT (WMATA)

E6F GREENBELT PARKWAY, WASHINGTON, D.C. 13

2.6. WASHINGTON METRO AREA TRANSIT (WMATA)

F10 SUITLAND PARKWAY, SUITLAND, MARYLAND 13

2.7. JFK LIGHT RAIL SYSTEM, NEW YORK CITY, NEW YORK 14

3. CASE STUDYKOLKATA METRO RAIL PROJECT

3.1. SALIENT FEATURES OF THE PROJECT 15

3.2. INTRODUCTION TO THE PROJECT 15

3.3. GENERAL OUTLOOK 16

3.4. SPECIAL REQUIREMENTS OF ELEVATED CORRIDOR 16

3.5. ERECTION PROCEDURE OF VIADUCT 17

3.5.1. STAGING THE SEGMENTS AT SITE 18


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3.5.2. PLACING AND FABRICATION OF LAUNCHING GIRDER 18

3.5.3. LIFTING AND STARIGHTENING OF SEGMENTS 20

3.5.4. DRY MATCHING AND GLUEING OF SEGMENTS 22

3.5.5. POST-TENSIONING 26

3.5.6. CLEANING OF SHEATHING PIPE 28

3.5.7. GROUTING OF SHEATHING PIPE 29

4. FIXING OF ELASTOMERIC BEARING

4.1. MATERIALS REQUIRED 33

4.2. PROCEDURE 33


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1. INTRODUCTION TO SEGMENTAL CONSTRUCTION1.1. What is Segmental Construction ?

As bridge spans increased in length, it became apparent that conventional precast prestressed

concrete girders would soon be limited by their maximum transportable weights and /or

lengths. For example, when delivered over highways, the length of precast girders is usually

limited to 100ft (30 m) maximum.

The answer to this problem lay in the development of precast prestressed segmental

construction in which the benefits of both precasting and post-tensioning could be combined

advantageously.

In segmental construction, large quantities of high quality of precast units (or segments) are

manufactured under controlled factory conditions and then transported with conventional

carriers to the job site. There, the segments are assembled easily, and lifted into place on the

superstructure. The segments themselves are then tied together using post-tensioning.

1.2. Developement of Segmental Construction of Bridges

Before the advent of segmental construction, concrete bridges would often be made of several

precast girders placed side by side, with joints between girders being parallel to the

longitudinal axis of the bridge. With the modern segmental concept, the segments are slices

of a structural element between joints which are perpendicular to the longitudinal axis of the

structure.

When segmental construction first appeared in the early 1950s, it was either cast in

place as used in Germany by Finsterwalder et al., or precast as used in France by Eugne

Freyssinet and Jean Muller. The development of modern segmental construction is

intertwined with the development of balanced cantilever construction.By the use of the term balanced cantilever construction, we are describing a phased

construction of a bridge superstructure. The construction starts from the piers cantilevering

out to both sides in such a way that each phase is tied to the previous ones by post-tensioning

tendons, incorporated into the permanent structure, so that each phase serves as a

construction base for the following one.

The first attempts to use balanced cantilever construction, in its pure form, were made

by Baumgart, who in 1929 built the Ro Peixe Bridge in Brazil in reinforced concrete, casting

the 68-m-long main span in free cantilevering. The method did not really prosper, however,


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until the post-tensioning technique had been sufficiently developed and generally recognized

to allow crack-free concrete cantilever construction.

From 1950, several large bridges were built in Germany with the use of balanced

cantilever construction with a hinge at midspan, using cast-in-place segments, such as

Moselbrcke Koblenz, 1954: Road bridge, 20 m wide, with three spans of 101, 114,123 m plus short ballasted end spans hidden in large abutments; the cross section is

made up of twin boxes of variable depth, connected by the top slab.

Rheinbrcke Bendorf, 1964: Twin motorway bridges, 1,031 m long, with three mainriver spans of 71, 208, 71 m, built-in free cantilever construction with variable depth

box sections.

In France, the cantilever construction took a different direction, emphasizing the use of

precast segments.

Precast segments were used by Eugne Freyssinet for construction of the well-known

six bridges over the Marne River in France (1946 to 1950). The longitudinal frames were

assembled from precast segments, which were prestressed vertically and connected by dry-

packed joints and longitudinal post-tensioning tendons. Precast segments were also used by

Jean Muller for the execution of a girder bridge in upstate New York, where longitudinal

girders were precast in three segments each, which were assembled by dry-packed joints and

longitudinal post-tensioning tendons.

From 1960, Jean Muller systematically applied precast segments to cantilever

construction of bridges. It is characteristic for precast segmental construction, in its purest

form, that segments are match cast, which means that each segment is cast against the

previous one so that the end face of one segment will be an imprint of the neighbor segment,

ensuring a perfect fit at the erection. The early milestones were as follows:

Bridge over the Seine at Choisy-le-Roi in France, 1962: Length 37+55+37 = 130 m;

the bridge is continuous at midspan, with glued joints between segments (first precast

segmental bridge).

Viaduc dOleron in France, 1964 to 1966: Total length 2862 m, span lengths

generally 79 m, with hinges in the quarterpoint of every fourth span; the segments were cast

on a long bench (long-line method); erection was by self-launching overhead gantry (first

large-scale, industrialized precast bridge construction).

In the same period, precast segmental construction was adopted by other designers for


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bridge construction with cast-in-place joints. Some outstanding structures deserve mention:-

Ager Brcke in Austria, 1959 to 1962: Precast segments placed on scaffold, cast-in-

place joints.

Ro Caroni in Venezuela, 1962 to 1964: Bridge with multiple spans of 96 -m each.

Precastsegments 9.2 m long, were connected by 0.40-m-wide cast-in-place joints to constitute

the 480-m-long bridge deck weighing 8400 tons, which was placed by incremental launching

with temporary intermediate supports.

Oosterschelde Bridge in The Netherlands, 1962 to 1965: Precast segmental bridge

with a total length of 5 km and span lengths of 95 m; the precast segments are connected by

cast-in-place, 0.4-m-wide joints and longitudinal post-tensioning.

Since the 1960s, the construction method has undergone refinements, and it has been

developed further to cover many special cases, such as progressive construction of cantilever

bridges, span-by-span construction of simply supported or continuous spans, and precast-

segmental construction of frames, arches, and cable-stayed bridge decks.

In 1980, precast segmental construction was applied to the Long Key and Seven Mile

Bridges in the Florida Keys in the United States. The Long Key Bridge has 100 spans of 36

m each, with continuity in groups of eight spans. The Seven Mile Bridge has 270 spans of 42

m each with continuity in groups of seven spans. The spans were assembled from 5.6-m-long

precast segments placed on erection girders and made self-supporting by the stressing of

longitudinal post-tensioning tendons. The construction method became what is now known as

span-by-span construction.

Comparing cast-in-place segmental construction with precast segmental construction,

the following features come to mind:-

Cast-in-place segmental construction is a relatively slow construction method. The work

is performed in situ, i.e., exposed to weather conditions. The time-dependent deformations ofthe concrete become very important as a result of early loading of the young concrete. This

method requires a relatively low degree of investment (travelers).

Precast segmental construction is a fast construction method determined by the time

required for the erection. The major part of the work is performed in the precasting yard,

where it can be protected against inclement weather. Precasting can start simultaneously with

the foundation work. The time-dependent deformations of the concrete become less

important, as the concrete may have reached a higher age by the time the segments are placed

in the structure. This method requires relatively important investments in precasting yard,


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molds, lifting gear, transportation, and erection equipment. Therefore, this method requires a

certain volume of work to become economically viable. Typically, the industrialized

execution of the structure leads to higher quality of the finished product.

Since the 1960s, the precast segmental construction method has won widespread

recognition and is used extensively throughout the world. Currently, very comprehensive

bridge schemes, with more than 20,000 segments in one scheme, are being built as large

urban and suburban viaducts for road or rail. It is reasonable to expect that the precast

segmental construction method, as introduced by Jean Muller, will contribute extensively to

meet the infrastructure needs of humankind well into the next millennium.

The first segmental concrete bridge, built in 1950, was cast-in-place across the LahnRiver in Balduinstein, Germany.

The first precast segmental concrete bridge, built in 1962, crossed the Seine River inFrance.

The first U.S. precast segmental concrete bridge, built in 1973, in Corpus Christi,Texas.

The first U.S. cast-in-place segmental bridge, built in 1974, was built near San Diego,California.

The first U.S. precast segmental oncrete arch bridge is the Natchez Trace ParkwayBridge, completed in 1993.


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2. LITERATURE STUDYCase studies of Segmental Bridges.

In a large majority of cases, segmental construction has been the winner where alternative

construction methods have been available to the contractors at the time of bidding due to its

numerous advantages over other methods. Some of the cases where segmental construction

has been a success are discussed below.

2.1. Chesapeake & Delaware Canal Bridge, St. Georges, Delaware, USA

The Chesapeake & Delaware Canal Bridge (officially the Senator William V. Roth, Jr.

Bridge) is a concrete and steel cable-stayed bridge that spans the Chesapeake & Delaware

Canal near St. Georges, Delaware. The bridge is located near a tolled section of Delaware

Route 1 that runs parallel to the St. Georges Bridge carrying U.S. Highway 13. In November

2006, the bridge was named after U.S. Senator William V. Roth, Jr., who not only lent his

name to the Roth IRA, but was instrumental in securing federal funding to build the bridge. It

is owned and operated by the U.S. Army Corps of Engineers and does not carry a toll, despite

the location of a nearby toll plaza.

The C & D Canal Bridge, the first cable-stayed bridge of its type in the Delaware Valley area(all previous Delaware River or C & D Canal bridges are either suspension, cantilever, or

simple truss designs), is also the first pre-cast concrete bridge to be built in the United States.

Modeled after that of the Sunshine Skyway Bridge in St. Petersburg, Florida, the bridge

incorporates many features not found on the other canal bridges:

1. Fixed high-level crossing, a 100 feet (30 m) clearance like that of the other Canalhighway crossings.

2. 750 feet (229 m) center span, with the major anchorages out of the water (thuspreventing a catastrophic collision similar to the old Sunshine Skyway Bridge and

previous C & D Canal bridges)

3. Six travel lanes, with the option of restriping to eight4. Pull-off emergency shoulders on both sides (under the current striping arrangement)5. Roadway lighting they were removed in 2003 at the requests of canal pilots and

replaced with low-voltage low-pressure sodium floodlights that illuminate the main

support anchors


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6. 65-mph speed limit7. Separate approach spans, only joining at the anchorages of the cables

The bridge also incorporates a 3% climbing grade, a feature lacked on the nearby St. Georges

Bridge. The bridge, built between 1991 and 1994, utilized pre-cast concrete segments that

were made in Baltimore, Maryland, and transported by barge until it reached the job site.

Once at the site, the segments were fitted into place like that of a jigsaw puzzle.

2.2. Linn Cove Viaduct, Carolina

Linn Cove Viaduct is a 1243-foot concrete segmental bridge which snakes around the slopes

of Grandfather Mountain in North Carolina. It was completed in 1983 at a cost of $10 million

and was the last section of the Blue Ridge Parkway to be finished. It is said to be the mostcomplicated concrete bridge ever built.

The viaduct was needed because of the damage that a traditional cut-and-fill road would have

caused to Grandfather Mountain. The viaduct was designed by Figg and Muller Engineers,

Inc.; construction began in 1979. It is 1,243 feet long and consists of 153 segments weighing

50 tons each. The bridge's segments were precast at an indoor facility at the south side of the

parkway. After being transported to the bridge site, each section was lowered into place by a

custom crane placed on either edge of the existing structure. The only work done at ground

level was drilling for the seven footings which support the viaduct. In particular, there was no

access road other than the Blue Ridge Parkway itself. The bridge has received eleven design

awards.

2.3. John T. Collinson CSX Rail Bridge, Pensacola, Florida

This bridge was completed for CSX Transportation in 1988 as the first precast segmental

bridge for heavy rail use in the United States. The bridge was designed for Cooper E90 trainloading, hurricane winds, and barge impact. At 11,370 feet, it is the longest rail bridge in the

United States. It crosses the Escambia Bay with typical 100 simple spans and a 170 main

span over the navigation channel. An interesting feature about this bridge is its contingency

plan for a derailment condition. In the event of a derailment that results in the loss of a span,

there is an entire span of segments and the erection truss in storage near the site, ready to be

installed to open the bridge to operation immediately. This demonstrates the flexibility of

precast segmental construction and the ability to tailor the construction method to the specific

needs of an owner.


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2.4.Metropolitan Atlanta Rapid Transit Authority(MARTA) CS360 & CN480,

Atlanta,Georgia

This bridges completed in 1983, were the first precast segmental concrete bridges built for

rail use in the United States. The precast segmental design was also the first use of twin

triangular trusses located on each side of the box girder and supporting the box from

underneath the wings. This span-by-span construction method allowed adequate vertical

clearance while building over traffic and in heavily congested areas. MARTA CS360 is

5,230 long, carrying two trackways and consisting of simple spans ranging in length from

70 to 100. MARTA CN480 is 1,900 long with span lengths ranging from 75 to 143. A

single box section7 deep and 30-4 wide was used for the entire combined alignment of

7,130.

2.5.Washington Metro Area Transit (WMATA) E6F Greenbelt Parkway,

Washington, D.C.

These twin precast segmental transit rail viaducts were completed in December 1990. The

bridges consist of a combined 3,846 structure length with typical spans of 109 and with

variations from 49 to 133. Span-by-span construction was used with a steel erection truss

supporting the box girders under the bottom soffit, easily accommodating the horizontal

curvature radii of 1,200' of the viaduct without disturbing the nearby wetlands. To

accommodate track super-elevation that varies from 10% to 0% while minimizing the vertical

profile, two parallel box girders were chosen for the superstructure. Each girder is 15.5' wide

and 7 deep and carries a single track with rails fixed directly to the superstructure.

The successful low bid contractor selected the precast segmental design over a concrete cast-

in-place on falsework design, providing a savings to WMATA that is reflected in the low bid

of $9.4 million for their key project.

2.6.Washington Metro Area Transit (WMATA) F10 Suitland Parkway, Suitland,

Maryland

This mass transit project is an extension of the existing transit system in Washington, D.C.

Project challenges included building over busy Suitland Parkway, minimizing disruption to

environmentally sensitive wetlands, and providing an aesthetic solution for the adjacent

national parklands. Precast concrete segmental construction successfully fulfilled all of the

projects needs. The total project length of 2,620 consisted of spans ranging from 56 to 151


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with typical spans of 132. The simple spans were built using span-by-span construction built

from above to protect the wetlands and maintain traffic on the parkway below. The constant

8-8 deep and 32-5 wide box was used throughout the project, which included ten

horizontal curves, two vertical curves, and cross-slopes of up to 12%. The $10.7 million

bridges were completed in February 1999, well ahead of the October 1999 anticipated project

completion.

2.7. JFK Light Rail System, New York City, New York

Nearly nine miles of elevated structure were built in the congested JFK Airport and

surrounding areas in New York City. This light rail system was built to connect the separate

terminals of the airport to each other, long-term parking, the commuter rail line, and the New

York subway system. The project utilized 5,409 precast segmentsthe most of any bridge in

the United States. Construction was completed over existing at-grade roadways with traffic

flowing. One 2.3-mile section of the project was built in the median of the existing Van

Wyck Expressway. Three lanes of traffic in each direction continued as construction was

progressed at a rate of 2 spans of 120 per week. The finished base of the column and

barriers is only 7-8 in order to utilize the median as the only available space for support

columns.

Precast segmental construction was particularly innovative for this aggressive project. In

order to simplify the complexities on the project, two 7-0 deep box sections were utilized

one for the single track section (19-3 wide) and one for the dual track section (31 wide).

These two sections were able to accommodate variable span lengths from 62 to 156 and

horizontal curvature with radii as small as 212.

Precast segments were cast in Cape Charles, Virginia, barged 250 miles to Camden, New

Jersey, and then trucked over 100 miles to the site. Storage of materials on-site was a

significant issue, so planning of segment delivery was critical. The average storage time at

the site was two days before erection. The planning and coordination was successful,

indicated by the completion of nine miles of elevated structure in only 26 months, almost 3

months ahead of schedule.

The closed box girder shape creates a smooth underside for the structure, allowing clean lines

and uncluttered appearance. The concrete mix was closely regulated, using specific materials

to generate the same concrete color whether it was precast (superstructure), cast in place

(substructure), or mixed on-site (closure pours).


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3. CASE STUDYPROJECT :- PART DESIGN AND CONSTRUCTION OF 4.725 KM VIADUCT FOR

KOLKATA METRO RAIL CORPORATION.

3.1. SALIENT FEATURES OF THE PROJECT :-

1. SCOPE OF WORK :- Part design & construction of 4.725km viaduct from chainagekm 7.763 to km 13.328 and viaduct connection to central park depot (1.048km) and

portals for junction arrangement for future link to airport (elevated section) of East

west corridor of Kolkata metro excluding viaduct at stations namely salt lake stadium,

Bengal chemical, city centre, central park, karunamoyee & salt lake sector-V each of

length 140m on subhash sarobar to salt lake sector-V.

2. CONTRACT PRICE :- Total cost of the project: Rs. 212,53,60,000/-Schedule A: Lump sum basisRs. 188,00,00,000/-

Schedule B: item rate Contract Rs 9,03,60,000/-

Schedule C: %age over Item Rate Contract Rs 6,75,00,000/-

Schedule D: %age on Lump sum Amount Contract Rs 8,75,00,000/-

3. TYPE OF CONTRACT :- Lump Sum for Viaduct portion and Item Rate for otherItems of work.

4. NAME OF CLIENT :- Kolkata Metro Rail Corporation Ltd. (KMRCL)/5. NAME OF CONTRACTOR :- GAMMON INDIA LIMITED.

3.2. INTRODUCTION TO THE PROJECT :-

With a view to reducing the problems of Kolkata commuters like congestion on roads, ever

slowing speed, increasing accidents rate, fuel wastage, and environmental pollution, Kolkata

Metro Rail Corporation Limited (KMRCL) has under taken the construction of Mass Rapid

Transit System for Kolkata. The entire work under the scope of Gammon India ltd is of the

length of 4.725 km viaduct from chainage km 7.763 to km 13.328.

The construction of the superstructure of such long distance of viaducts has not only to meet

the functional requirement but also to take care of the site constraints such as


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i) Allowing free flow of vehicular traffic on the already congested along withchosen alignment,

ii) Paucity availability of land,iii) Existence of charted and uncharted utilities, problems to pedestrians,iv) Problems to existing residents, andv) Environmental impact including noise and vibration etc.3.3.GENERAL OUTLOOK :-

To select the type of Metro Rail corridor -

I. A comprehensive multimode mobility study, taking into account the various transport

means like Rail/Sub urban /Metro/Roads/Feeder services, is required to be conducted to

finalized the change over points.

II. A combination of route i.e. elevated, at par, and under ground is then selected considering

their

Impact on the profile of the city

The elevated corridor is planned by KMRCL generally to cut across fairly densely built up

areas by virtue of its need to serve these area Hence its impact needed sensitive treatment

and assessment. Thus, the sometimes conflicting issues of operations and using requirements,

construction appearance, environmental impact, including noise and vibration had to be

included in the overall assessment of the most appropriate materials and form of construction.

3.4. SPECIAL REQUIREMENTS OF ELEVATED CORRIDOR :-

DURING CONSTRUCTION

The construction of the superstructure of such long distance of viaducts has not only to meet

the functional requirement but also to take care of the site constraints such as :-


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1) Allowing free flow of vehicular traffic on the already congested along with chosen

alignment,

2) Paucity availability of land,

3) Existence of charted and uncharted utilities,

4) Problems to pedestrians,

5) Problems to existing residents, and

6) Environmental impact including noise and vibration etc.

Mitigation Measures

To have minimum inconvenience to general public the following mitigation measures are

required

a. Fully barricading the construction corridor,b. Providing proper signage and lighting arrangement,c. Completing the construction in a minimum time frame and in a time bound manner,d. Good house keeping of the surrounding area, ande. Raising the confidence of the public by adopting safety measures, caring for public

attitude.

3.5.ERECTION OF VIA-DUCT

The superstructure is be erected entirely from below using an under slung erection tackle.

ERECTION PROCEDURE :-

The erection procedure consist of several part work those are listed below :-

(i) Staging the segments at the site.(ii) Fabrication of launching girder.(iii) Launching and straitening of segments.

(iv)Fixing the edges of segment with water cement mixture.(v) Post-Tensioning.(vi)Cleansing of seething pipe.(vii) Grouting.


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3.5.1. STAGING THE SEGMENTS AT SITE :-A. Transportation of segments by trailers will pose serious problems in crowded city

roads and sharp curves.

B. Operation of two cranes to place segments in position will require traffic block duringnight for a no. Of night which may not be acceptable to traffic police and if agreed

upon they will causes inconvenience to general public.

C. The availability of casting yard at suitable location as choice will be governed byshifting, lifting and transportation of girders.

D. Cast in situ construction, where ever required is time consuming and causesinconvenience to public.

Considering these conditions segments are staged at site.

3.5.2. PLACING AND FABRICATION OF LAUNCHING GIRDER :-The superstructure is be erected entirely by using erection tackle. In all through the training

period we are introduced with one type of tackle. That is supported on two or three

supporting legs. At initial of erection girder box is supported on two pier and on trussle. After

completing one span it is extended and slide with girder box supported on rear support and

rear trolley.

The over all system is a assembly of several individual parts and those are ---- 1) Girder

box; 2) Front, Middle & Rear support; 3) Sliders; 4) USA David Bar; 5) Stain-less Steel

Plate; 6) Hoist; 7) Hoist Cap; 8) Winch; 9) C-Link; and 10)Bolt of several diameter;

BOX GIRDER


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FABRICATION OF LAUNCHING GIRDER

The over all processing of fabrication is critical and risky. Based on the fabricated stage the

segments are erected and the spans are completed. Firstly four levelling bed of M 35 in

square shape are casted in one side of pier on which trusses are fabricated and stay head

straight. Then with the help of crane front supporting tools are established and then the

middle support is been placed then based on the supports girder boxes are lifted and placed.

Each girder box are of 9.250 m in length such five or more boxes are connected together with

the help of nut & bolts. This boxes are made with special criterion, at the top of it there is a

stainless steel rail with PTFE pad on which sliders ore placed each slider contain a winch this

both slider and winch are used to move the segment horizontally and vertically.. This winch

are of capacity 80T. In all through the work of fabrication of launching girder Metal Inert Gas

Welding and Tung Stain Inert Gas Welding are used in place of normal gas welding. For

safety purpose the girder system can carry more load which is just applied at the time of

fabrication otherwise accident will happen.

Advantages of PTFE sliding supports

The simplicity of the bearing design and its ease of fabrication and installation make the unit

cost efficient. The costs of a construction can be reduced by designing for expansion rather

than strain. Coefficient of friction over the bearing surface remains constant, even under

worst case conditions. bearings are maintenance free - PTFE is inherently self - lubricating,

while dirt particles are absorbed into the material. Only simple protection is required against

the significant increases of dirt.


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PTFE sliding supports

3.5.3. LIFTING AND STRAIGHTNING OF SEGMENTS :-

1. Lifting of Segments :-Lifting of segment shall be done with the help of gantry either from ground or

from trailer. GANTRY with segment shall be brought to exact position and placed

over respective jack trolley. Lifting of segment and keeping it above jack trolley shall

be repeated as above procedure for required no of segments.

2. Survey and Geometric control :- For survey and geometrical control we considerthree lines, one marked at casting yard during casting say (L1) and other marked over

pier cap/shear key block say (L2). Another line (L3) parallel to line (L2) is ranged at


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site during setting, dry-matching & gluing. In casting yard one arbitrary straight line

(Li) marked over embedded aluminum channel for both curved and straight span. At

site another line (L2) marked by joining as built center of pier caps (as-built bearing

of spans) over pier cap/shear key block.

While setting of S1 segment LI is matched to L2. The first segment should be placed

in such a way so that it is 50 mm away from transverse axis and as-cast center of

segment should match with as-cast center of pier cap also its marked reference line

(Li) on embedded aluminum channel at casting yard should be parallel to line (L3).

For leveling temporary bench marks shall be established. For dry matching & gluing

of other segments only leveling works are carried out.

WORKING LAUNCHING ARRANGEMENT


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3.5.4. DRY MATCHING AND GLUEING OF SEGMENTS :-a) Dry matching :- S1 segment shall be aligned to required geometry based on

theoretical Profile of the respective span and condition of loading on LG. After

setting of S1 segment, it shall be arrested from movement by providing packing

between pedestal and segment. Now the movement and rotation of S1 is arrested

temporarily. Then S2 shall be dry matched with S1 segment. After ensuring proper

closing of joint, S2 shall be pushed back about 200 mm backward for glueing.

b) Glueing of Segments :-Before stressing alignment of segment of a deck isimportant otherwise at time of stressing the alignment getting distorted . Only for

that a special kind of epoxy glue namely NITO BOND PC 30 of FOSROC companyis been applied thoroughly the side contains shear-keys. The glue is too harmful for

human skin so the gluing is done by wearing hand gloves.

Firstly gluing materials are mixed together homogenously in agitator mixture then it is

supplied for use purpose. Gluing at sides a circular foam pad is joined around the anchor cone

hole then two adjacent segments are pressed at a pressure around 250 to 400 kg/cm2. The

pressure is applied until the glue rise to outer faces.

Nito bond PC30Medium Fast set for application between 150 C to 300 C.

TECHNICAL SUPPORT

The company provides a technical advisory services supported by a team of specialists in the

field.

Properties :-

1. Colour BaseWhite2. HardenerBlack3. Mixed - Grey_4. Specific gravity at 300C is 1.601.655. Compressive @24 hours > 40 N/mm6. Strength @7 days > 75 N/mm7. Tensile bending strength Concrete failure Shear Strength 13 N/mm8. Chloride content Nil to IS: 456


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9. Air entrainment Approx 1% additional air is entrainedAPPLICATION INSTRUCTIONS :-

a.

Surface Preparation :-Concrete should be mechanically sound and free fromcontamination, such as free water, mould, oil or grease, laitance and dust. Grit

blasting is recommended. Sections to be bonded should be checked for good

alignment. A dry run before the first application of the adhesive is recommended to

ensure correct timing.

b. Mixing :- The base and hardener into a suitable container shall be emptied and mixwith a paddle and slow speed heavy duty drill, ensuring the sides are scraped down. A

uniform grey colour should be obtained after mixing thoroughly.

c. Application :- The mixed adhesive is applied to both surfaces to be bonded with aserrated trowel or other suitable spreader. The joint should be closed immediately, if

this is not achieved the surface of the adhesive should be slightly scratched

immediately prior to closing the joint to expose fresh adhesive. The joint must be

closed within the open time of the adhesive. On site monitoring of the operating using

lapped asbestos cement panels is recommended.

d. Cleaning of Application Equipment :- Tools and equipment should be cleanedimmediately after use with Nitoflor Sol.

e. Packaging:- 30 Litter . Bulk packs and 3.7 L standard packs.f. Coverage :- Approximately 2 L/m at 2 mm thickness.g. Storage :- At least 12 months if stored below 350 C in unopened containers

Precautions :-

1. Health and Safety :- Some people are sensitive to epoxy resin system and maydevelop dermatitis. Direct contact with eyes will cause serious damage if left

untreated. Any eye contamination should be washed thoroughly with water and

immediate medical attention should be sought. Gloves, barrier creams and eye

protection should always be used when handling Nitobond PC and Nitoflor Sol. If

contact with skin occurs, a resin removing cream should be used, followed by

washing with soap and water. Solvent shall not be used.


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2. Fire :- Nito bond PC base and hardener are non flammable, Nitoflor Sol idflammable. Do not use near flames. No smoking.

3. Flash Points :- Nito-bond PC Base 1000 C , Nito-bond PC Hardener 1000 C. NitoflorSol Solvent 330 C

Uses :-

To produce pump able concrete. To produce high strength, high grade concrete M30 & above by substantial

reduction on water resulting in low permeability and high strength.

To produce high workability concrete requiring little or no vibration during placing.Advantages

Improved workabilityEasier, quicker placing and compaction. Increased strength Provides high early strength for precast concrete with the

advantage of higher water reduction ability.

Improved qualityDenser, close textured concrete with reduced porosity andhence more durable.

Higher cohesion Risk of segregation and bleeding minimized; thus aidspumping of concrete.

Chloride free Safe in pre stressed concrete and with sulphate resistingcements and marine aggregates.

Standards compliance :- Conplast SP430 compiles with IS:9103:1999 and BS:5075 Part 3.

Conplast SP430 conforms to ASTM-494 Type F and Type A depending on the dosages

used.

Compatibility :- Can be used with all types of cements expect high alumina cement.

Conplast SP430 is compatible with other types of Fosroc admixtures when added separately

to the mix. Site trials should be carried out to optimize dosages.


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Workability :- Can be used to produce flowing concrete that requires no compaction. Some

minor adjustments may be required to produce high workable mix without segregation.

Cohesion :- Cohesion is improved due to dispersion of cement particles thus minimizing

segregation and improving surface finish.

Compressive strength :- early strength is increased up to 20% if water reduction is taken

advantage of. Generally, there is improvement in strength up to 20% depending upon W/C

ratio and other mix parameters.

Durability :- Reduction in W/C ratio enables increase in density and im-permeability thus

enhancing durability of concrete.

Application instructions :-

a. Dosage :-The optimum dosage is best determined by site trials with the concrete mixwhich enables the effects of workability, strength gain or cement reduction to be

measured. Site trials with Conplast SP430 should always be compared with mix

containing no admixture. AS a guide, the rate of addition is generally in the range of

0.52.0 litres/100 kg cement.

b. Over dosing:- An over dose of double the recommended amount of conplast SP430,will result in very high workability and some retardation of setting time will occur.

However, the ultimate compressive strength will not be impaired.

c. Mix design:- Fosroc has a dedicated advisory service on Concrete Mix design andcan be contacted if assistance is required.

d. Packing:- Conplast SP430 is supplied in 5, 20 and 200 litre drums.e. Storage :- Conplast SP430 has a minimum shelf life of 20 months when stored under

normal temperatures. It should be protected from extreme temperatures and preferably

stored in shade.

f. Typical results :- M-30 mix, Sand Zone 2 (40%), Coarse aggregate 20 - 5mm(60%)

g. Cement :- L&T OPC


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PRECAUTIONS TO BE CONSIDERED :-

Several precautions are to be taken this are listed below :-

i. Product should not come into contact with skin, eye or Be swallowed oninhaled.

ii. Wear suitable protective clothing like gloves and mask.iii. In case of contact with skin use that with cold pure water.

GLUEING OPERATION

3.5.5. POST TENSIONING :-After launching the segment, straightening and gluing a set of strand as per the design and

based on the length is been installed in the duct and at one end it is fixed with bearing, master

wage and with lock on the other end extended strands are connected with several tools those

are bearing, live wage, collar plate, lock, then guide tube and the guide tube is installed in

jack. This jack is connected with Hydraulic Power Pack and stressed. The tendons are laid

out in the forms in accordance with installation drawings that indicate how they are to be

spaced, what their profile (height above the form) should be, and where they are to be


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stressed. The tendons are stressed around 180mm (elongated) with a pressure as per drawing

and design and is in between 200Kg/cm2 to 300Kg/cm2 and anchored. The tendons, like

rubber bands, want to return to their original length but are prevented from doing so by the

anchorages. The fact the tendons are kept in a permanently stressed (elongated) state causes a

compressive force to act on the concrete. This pre compression which results from post-

tensioning counterbalances the tensile forces created by subsequent applied loading (cars,

people, the weight of the beam itself when the shoring is removed). This significantly

increases the load-carrying capacity of the concrete. Another advantage of post-tensioning is

that beams and slabs can be continuous, (i.e. a single beam can run continuously from one

end of the building to the other).

Post-Tensioning Systems

Structurally, this is much more efficient than having a beam that just goes from one columnto the adjacent column. Since post-tensioned concrete is cast in place at the job site, there is

almost no limit to the shapes that can be formed. Curved facades, arches and complicated

slab edge layouts are often a trademark of post-tensioned concrete structures. Post-tensioning

has been used to advantage in a number of very aesthetically designed bridges.

Many proprietary post-tensioning systems are available. Several suppliers produce systems

for tendons made of wires, strands or bars. The most common systems found in bridge


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construction are multiple strand systems for permanent post-tensioning tendons and bar

systems for both temporary and permanent situations.

COLAR PLATE, LOCK, GUIDE TUBE

STRANDS :- Strands are the special kind of steel it consist of high ductile property so tensile

tearing of it is very high. Strands are the set of seven HT wire is known as ply, its dimension

is 15.2mm in diameter and length is as per span. 1 strand can take maximum 26555 T load is

none as breaking load, and in stressing 70% to 80% of breaking load is applied.

Schematic of end, deviator and pier segments

showing the external tendon arrangement

Schematic of a deviator and a pier segment

showing tendon arrangement

3.5.6. CLEANING OF SHEATHING PIPE :-

Where the segments are casted that site is full of dust. So the ducts for stressing contain lot of

dust in it, after stressing or before grouting the ducts are cleaned with calcium oxide solution

i.e., a CaO and Water solution in a perfect ratio. CaO solution is use only that it can perfectly

clean the dust. Ti is injected inside duct with water pump and is push out with blowing pipe

to remove the internal cleansing material. The cleansing operation is also useful to detect the

leakage, if any where in duct leakage is present then cleansing material leak out this leakages


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are not removed but as substitute quick setting grouting materials are used. In such a manner

the cleansing and leakages of ducts are detected.

3.5.7. GROUTING OF SHEATHING PIPE :-Grouting is the another important part of erection. Is a kind of casting that happened through

seething pipe. And is done with a mixture of special kind of grouting material and water at a

desire temperature .

MATERIALS USED :-

I. G.P.2II. Hydro plug or, Rend co plug.

III. Distilled water.MACHINES USED :-

I. Agitator.II. Grout pump.

METHODOLOGY :-

After stressing and cleaning the duct is ready for grouting. Firstly the grouting materials and

distilled water (of temperature is in between 70 to 110 ) are put in the agitator and mixed

thoroughly in a thermal boundation and is in between 180 to 220 .

Thoroughly mixing the grouting mixture it is put on grout pump through the holes on anchor

cone plate grouting materials are injected inside the duct and then pressure is applied and

until the material over flowed from other side the operation is going on. The grouting is done

by applying pressure so it is called pressure grouting. Actually pressure is applied only the

reason is that no air entrapped in al through the casted duct.

This operation is applied to protect the H.T. wire from air, water and to give a maximum

flexural bond through the span.

GP2 (Free flow, high strength, non-shrink, cementations precision grout)

Uses :- GP2 is used for precision grouting where it is essential to withstand static and

dynamic loads. Typical applications would be grouting of base plates of turbines,


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compressors, boiler feed pumps etc., it can also be used for anchoring a wide range of fixings.

These include masts, anchor bolts and fence posts.

Advantages :-

Gaseous expansion system compensates for shrinkage and settlement in the plastic state.

No metallic iron content to cause staining.

Pre-packed material overcomes onsite-batching variations.

Develops high early strength without use of chlorides.

High ultimate strength ensures the durability of the hardened grout.

Free flow ensures high level of contact with load bearing area.

Properties :-

Compressive strength :- (BS 1881Part 116: 1983) Consistency :- Flow able (W/P 0.18) Tensile strength :-3.5N/mm @ 28days, (W/P0.18) Pullout bond strength :-17 N/mm @ 7days (W/P0.18) 20 N/mm @ 28days. Time for expansion :-Start: 20 minutes (after mixing) Finish: 120 minutes. Fresh wet density :-approximately 2220kg/m depending on actual consistency used. Youngs modulus :-28 KN/mm (ASTM 469- 94). Dynamic load resistance :-Specimens of GP2 remained undamaged. Even after

subjecting them to alternate loads of 5N/mm & 25N/mm at the rate of

500cycles/minute for two million cycles.

Coefficient of thermal expansion :-11 * 10^(-6) / C. Unrestrained expansion :-2-4 % in the plastic state enables to overcome shrinkage. Pressure to restrain :-0.004 N/mm approx. Plastic expansion


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Flow characteristics :- The maximum distance of flow is governed by the gap width and the

head of the grout. Typical data for flow design assuming grout is poured immediately after

mixing

Note: This table is based on the following factors temperature -30C; Water saturated

substrate; Minimum unrestricted flow width is 300mm.

Performance specification :-

All grouting shown on drawings must be carried out with a pre packed cement based

product which is chloride free.

It should be mixed with clean water to the required consistency. The grout must not bleed

or segregate.

A positive volumetric expansion shall occur while the grout is plastic by means of gaseous

system.

The compressive strength of the grout must exceed 50N/mm at 7days and 60N/mm at

28days.

The flexural strength of the grout must exceed 9N/mm @ 28days. The fresh wet density of

the mixed grout must exceed 2150kg/m3.

The storage, handling and placement of the grout must be in strict accordance with the

manufacturers instructions.

Mixing & placing :-

Mixing :- For best results a mechanically powered grout mixer should be used. When

quantities up to 50 kg are used, a heavy-duty slow speed drill (400-500 rpm) fitted with a

paddle is suitable. Larger quantities will require a heavy-duty mixer.

To enable the grouting operation to be carried out continuously, it is essential that sufficient

mixing capacity and labour are available. The use of a grout holding tank with provision to

gently agitate the grout must be used.

Consistency of grout mix :-The quantity of clean water required to be added to a 25kg bag

to achieve the desired consistency is given below :-


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Pourable :- 4.125 litres

Flowable :- 4.500 litres

The selected water content should be accurately measured into the mixer. The total amount of

the GP2 bag should be slowly added and continuous mixing should take place for 5 minutes.

This will ensure that the grout has a smooth even consistency.

Limitations :-

Low temperature working:- When the air or contact surface temperatures are 10C or

below on a falling thermometer, warm water ( 30-40C ) is recommended to accelerate

strength development. For the ambient temperatures below 10C the formwork should be

kept in place for at least 36 hours. Normal precautions for winter working with cementations

materials should then be adopted.

High temperature working :- At ambient temperatures above 40C, cool water (below

20C) should be used for mixing grout prior to placement.

PRECAUTIONS :-

Health and safety instructions :- GP2 is alkaline and should not come in contact with skin

and eyes. Inhalation of dust during mixing must be avoided. Gloves, goggles and dust mask

should be used. If contact with skin occurs, it shall be washed with water. Splashes to the

eyes should be washed immediately with plenty of clean water and medical advice sought.

Fire :- GP2 is non-flammable.

4.

FIXING OF ELASTOMERIC BEARING :-

After launching and prestressing the span was lowered on temporary stools.The launching

truss was moved ahead. Thus, there was no additional load on the span. Elastomeric

bearings were fixed true to the line and level between pedestals and soffit of the span

.Pedestal height was calculated considering 250mm gap at the centre of the pier, height of

bearing, 25mm non-shrink grout below bearing, and concrete projection below segment

soffit to nullify gradient of span.


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MATERIALS REQUIRED :-

Elastomeric bearings.

Angle shutters. Lifting hydraulic jacks. Non shrink grout. Bearing holding frame. Car Jacks.

PROCEDURE :-

1. Shifting and storingBearings were shifted from the main store and stored in proper place at site to avoid

mechanical damage, contamination with oil, grease and dirt, and undue exposure to

sunlight.

2. Span leveling and alignment

a. Hydraulic jacks of required capacity were placed in position as specified inthe drawing for lifting and shifting the span.

b. Span was leveled and shifted by operating hydraulic jacks to the required leveland alignment with respect to line L2 already marked on pier caps or shear key

blocks at the time of segment launching.

Elastomeric bearings


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c. Required expansion gaps were maintained with respect to the transverse axis ofthe pier.

The following points were taken into consideration for leveling and alignment of span :-

Aesthetically matching with the adjacent span. Matching with theoretical centerline of the span and leaving required expansion gap. Providing minimum required gaps between bearings and pedestal for grouting

with non-shrink mortar.

3. Surface PreparationAfter the alignment and leveling of span, temporary structural stools were removed from

pedestal. Pedestal top as well as segment soffit surface were cleaned and contaminants if

any like oil, grease, dirt etc. were removed.

4. Placing and grouting of bearing The bearing was placed inside the holding frame. The plate was positioned torequired level and alignment in exact position as indicated in drawing.

This was checked with spirit level in both longitudinal and transverse directions. The plate was lifted with the help of four car jacks all around through theangle ear welded with the plate to apply vertical force through car jacks.

It was ensured that the bearings are not displaced from their position duringand after this operation.

The bottom shutter was placed and non-shrink grout was poured by gravity flow.5. Span Lowering

After grouting the span was left for sufficient time for achieving 20MPa strength of

grout. Then the span was lowered slowly by operating hydraulic jacks to transfer theload to pedestals.


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Launching of Viaduct

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Transcript of Launching of Viaduct