BSCPL Infrastructure Pvt. Ltd

@ CONSTRUCTION OF BRIDGE IN NH-53,

In Arang to Saripali Road, (C.G.)An In-plant Training Report

 Submitted by

 SUKHDEEP SINGH JAT

U12CE117

In partial fulfillment for the award of the degree of

BACHELOR OF TECHNOLOGY

IN

CIVIL ENGINEERING

 

BSCPL Infrastructure Ltd is an ISO 9001: 2000 accredited infrastructure development company. Which pioneers in execution of Road Projects, Irrigation projects and recently diversified in Real estate and Hydro Power plants. Started as B Seenaiah and Co, a partnership firm in 1982. Later it converted into a Public Company in 1998 as B. Seenaiah and Company (Projects) Ltd and it was again renamed as BSCPL Infrastructure Ltd in 2008.

ABOUT THE COMPANY

ABOUT THE PROJECT

This superstructure falls in between the NH-53 connecting states of Gujarat,

Maharashtra, Chhattisgarh and Orissa. This Bridge is being built on the Mahanadi River near

Arang. The company holds the contract of developing and reconstruction of NH-53 of about 250

km in length starting from Arang to Saraipaali (Basna) near Orissa border. This highway is

undergoing numerous construction of bridges, flyovers, canals etc,.

This road laid on the bridge has to be of four lane road intensifying the traffic to its

maximum. This road connects the Rajim (District) to the developed cities leading to immense

means of transport. The major objectives of the project is :-

(i) to cover for the damaged bridge shortening the distance between to major cities

for Rajim.

(ii) to broaden the road for the transportation purpose.

(iii) to repair the damaged roads minimizing the road accidents.

Figure 1.1. Index Map Showing the Road (Arang to Sariapali)

DESCRIPTION ABOUT SUPERSTRUCTURE

The type of bridge that is being constructed over Mahanadi in Chhattisgarh is known as

Segmental Bridge. A Segmental Bridge is type of bridge built in short sections (called

segments).ie., one piece at a time. The bridge is made of concrete that is either cast-in-place

(constructed fully in its final location) or precast concrete structures ( built at another place and

then transported to their final location for placement in the superstructure).

Figure 2. A Picture Representing Ongoing Construction

DATA NEEDED FOR DESIGNING A BRIDGE

Geographical Details

• A plan of the site showing all the obstacles to be bridged such as rivers, streets, roads or railroads, the contour lines of valleys etc.

• Required width of the bridge, width of the lanes, walkways, safety rails, crash barriers etc.( this bridge is designed as four lane of the national highway).

• Soil conditions for foundations, results of boring with a report on the ground and the soil mechanics data.

Site Details

Here the site exploration is done by Boring. The site when explored provided the data are as follows :-

(I) Depth, extent, and composition of critical soil strata,

(II) Ground water level and its fluctuation

(III) Depth of bed rock(when necessary),

(IV) Estimate of engineering properties of soil,

(V) Initial selection of foundation possibilities,

(VI) Subsurface property of the area,

(VII) Evaluation of settlement characteristics of various soil layers,

(VIII) Evaluation of bearing capacity of the soil.

Figure 3. Above Diagram representing results of Boring

MATERIALS USED IN STRESSING

1) Bearing Plate

All the cables passing

through the ducts are

held together in the plate

with holes. The cables are

stressed after clinging the

live wedge into the holes

of the plate so that the

cables holds up to the

stressingFigure 4. Plate through which pipes are strands are coming out

2) Live Wedge

It’s a circular clamp

for hooking up the

cable strand to the

bearing plate. It holds

the most major part in

stressing. The live

wedge actually holds

to the another side

with the plate with

the cables in it while

stressing and clings to

the other side so that

the cables should

remain stressed.

Figure 5. Live Wedge

3) Collar Plate

It’s a cap to the

bearing plate. After

the stressing is done

the strand is left up to

an extent and then the

bearing plate is

covered with the

collar plate fitting it

with the screw.

Figure 6. Cap of the Bearing Plates

4) 7 ply pipe strand

This cable is referred

as the 7 ply pipe

strand its because of

the seven cables of

diameter 2mm are

strangled in one in a

helical manner and

the whole diameter of

the cable strand is

7mm. Each strand

passing through the

ducts holds the

capacity of holding

80 tons of loadFigure 7. Cable strand

4) Resin and Hardener

This chemicals are

mixed in the ration of

1:2 (Resin:Hardener )

and applied at the

front and back surface

of the segment after

dry matching.

Figure 8. Chemical used for GluingResin Hardener

MACHINES USED IN CONSTRUCTION

Figure 9. Launching Girder

Work :- The picture showing

above is of Launching Girder

which is used for the segment

feeding and laying out the span

in a Segmental Bridge

construction. The top portion of

the Launching Girder is known

as gantry which is used to lift the

supports and drag to the point

where it has to be fixed next. The segments were supposed to be hold up by the clamp attached

with the sliders and were moved towards the direction of the next span being build and aligned.

1. LAUNCHING GIRDER

Figure 10. Multi Strand Hydraulic Stressing JackThese hydraulic jacks are used to stress the cable strands passed through the ducts to make

the whole span into one. The strands were clamped with the live wedges on one side and

were stressed using the stressing jacks leaving the 5% of slip in length from the rear

portion considering the strands have been stressed properly.

2. Hydraulic Stressing Jack

A BRIEF EXPLANATION OF LAYING OUT ONE SPAN

1. The machine shown in the above provided picture is known as Launching Girder.

2. It stands on the pier of the bridge with the supports placed at the piers .i.e., front, middle and

rear support.

3. Front support is provided at edge of the span from where the next span has to be started and

the second support is provided at the second last pier from the where the next span to be

made while the rear support is provided for stabilizing the girder

4. The entire weight of the launching girder is hold on the hydraulic jack.

Figure 11. Construction Of Bridge on Mahanadi River

Figure 12. Hydraulic Jack

5. This hydraulic jack has the capacity of holding up to 500 ton of the load by itself.

6. Then the next step comes .i.e., Auto launching. It refers to the moving of the entire

launching girder to the next pier. The middle support was held by the gantry and it's

sliding through the structure moving for the next support.

Here are some of the photos showing the auto launching process:-

Figure 13 (a) Figure 13 (b)

Figure 13 (c)

7. Level checking and support fixing:- While the erecting of the segment middle support and

front support should be at the same level. Middle support on temporary tower. The levelling

for the middle and front support is done using Dumpy Level.

Figure 14. Pre-Casted Structure

8. When the auto launching is

done and support for the

girder is settled than the

segment feeding is

done ,.i.e., the segment is

lifted by the gantry and

then it is transferred to the

slider which holds up the

pre-cast concrete structures

as a temporary.

9. Dry matching:- It is the alignment of the segment in their places.

10. Gluing:- pasting of two segments with the calculated load with the mixture of hardener

and the resin with the ration of 1:2.

11. When the structures are held by the sliders and the segments are joined then the strands

of 7 ply pipe( used in this bridge as prescribed in the drawings) is inserted through the

ducts joining all the segments.(one strand can approx. carry the load of 20 ton). This

process is known as "Threading".

This is how it looks after threading all the clamps holding the segments are held by the

sliders and the structure is balanced and the total load is transferred to the jacks.

12. Stressing is done once the span is been held temporary making the span still after the

removal of clamps holding the bridge.

13. When once the stressing is done then we move on to the "Grouting", which means applying

the cement and cebexes mixture with water with the applied air pressure into the ducts.

Figure 15 Clamps holding the segment

14. Grouting is done to prevent the corrosion that may occur in the stressing pipe and maintains

its property for a long period.

15. But before grouting it has to be made sure if the ducts have any leakage holes or not because

if there will be a leakage then the mixture applied throughout the duct may not be settled

properly. Thus, it is checked by applying the limewater though the duct within a applied

water pressure.

16. After grouting the two span is joint with the expansion joint and after putting the expansion

joint cast-in-situ is done.

REFERENCES

 

1. Soil Mechanics and Foundation by Dr. B.C. Punmia.

2. Structural Analysis by S.S. Bhavikatti.

3. Jr. Engineer Sourabh Sinha at BSCPL Infrastructure Pvt. Ltd.

4. Wikipedia

THANK YOU