Case Study: Rehabilitation of Mahatma Gandhi Setu

Mar 10

The importance of MG Setu is very critical, as it carries more than 40,000 vehicles per day and provides livelihood to 2 lakh people with connecting Bihar to all local markets. Understanding the importance, tenders were floated by MORTH to replace the entire Cantilever Segment Structure with Steel Truss Girders. The Project was awarded to M/S AFCONS SIBMOST JV under the PMC of M/S TPF Engineering.

Construction by Gammon
The bridge consists 45 intermediate spans of 121.065 m (397.19 ft.) each and a span of 65.530 m (214.99 ft.) at each end. The deck provides for 7.5 m
(25 ft.) wide two-lane roadways for IRC class 70 R loading with footpaths
on either side. The cantilever segmental construction method was adopted to construct this mega bridge.

Challenges in this Process
The Bridge is having 46 piers in total out of which 26 comes in Ground Zone, 10 nos. in Season Flow Zone and 10 nos. over the River Ganges. The challenge was that no debris can fall in the holy river. Water spans are in high current flow zone.

Involvement of Dextra India

Rehabilitation Process

RepairGrip Couplers
- Dextra India supplied repair grip couplers for the connection of existing bars with new extension bars for pier cap.
- Diameter of RG couplers are 16 mm, 20 mm, 25 mm, 32 mm and transition couplers of RG TC 32-28 and RG TC 25-20.
- Each pier consists of average 280 bars.

Fully Threaded Bar System
Dextra India supplied Fully Threaded Bar System to control vibrations of piers during as traffic was actively passing through downstream.

Preparation of Single Side Crimping at Steelyard
- Rebar ends are cleaned with the help of a wire brush to clear the rust.
- Couplers & rebars are then marked to ensure that the second bar have sufficient embedment in sleeve.
- Sleeves are the punched over rebar with the help of a hydraulic Powerpack

Final Crimping at Site
- Rebar ends are cleaned with the help of a wire brush to clear the concrete and dusts.
- Existing rebars are checked and marked by engineer for cutting the heads for proper butt joint.
- Rebars are then straightened by the help of mechanical tools. After this single side crimped rebars are placed over the existing bars.