Revamped MG Setu, India’s longest steel bridge, becomes fully operational

Engineering Marvel

Patna: A fully renovated and operational Mahatma Gandhi Setu (MG Setu) will be available for traffic after the eastern flank of the bridge, to be inaugurated by Union Minister for Road Transport and Highways (MORTH) Nitin Gadkari today (June 7). The 39-year-old MG Setu over river Ganga will become the longest steel bridge in the country with a length of approximately 5.60 Km.

The MG Setu was opened as the first balanced cantilever bridge in the country in 1982, which has been dismantled and converted into a simply supported bridge. The Afcons Constructions launched work of reconstruction in 2017. The existing concrete substructure is retained, and the superstructure has been replaced by steel deck superstructure. The western flank was inaugurated in 2020. It is a short of remarkable that a complex bridge rehabilitation project of this scale is completed in five years.

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Reminiscing the journey of reconstruction, project manager of Afcons constructions, SK Misra said, “Earlier there used to be a waiting period of 3-4 hours in case of traffic jams and due to the poor condition of the bridge. But now the traffic will be able to cross the bridge in just 15-20 minutes.”

Almost over a lakh of passenger vehicles cross the bridge every day. The bridge is vital to the state’s socio-economic development because it connects north and south Bihar.

Engineering marvel

“We completed the entire downstream lane (eastern flank) in 18 months and various factors helped to speed up the construction works. There was huge learning, when we were working on the upstream side (western flank). Fabrication of trusses of the downstream side was done in advance. We improvised and innovated in our dismantling methodologies like use of holding frame for wet spans. We worked parallelly on pier modification and truss erection,” Misra said.

The biggest concern in the project was the running traffic in the adjacent bridge at all times. “At the top of it, we had to handle a huge volume of dismantling works with environment-friendly disposal of waste material. We had to make sure that no debris from bridge demolition settled into the river,” Misra said.

Engineering marvel

Almost 66,360 metric tonnes of steel have been used in the entire bridge superstructure. Elaborating on this massive volume of steel usage the project manager said, “The steel works were a massive scope in the project. Procurement and fabrication works were completed through suppliers and workshops across India.”

Construction of a river bridge is always fraught with danger especially in flood-prone areas. The risk was high in case of MG Setu too. “During monsoon we had to negotiate up to 7m of water level rise and high currents in the river zone. Flooding was normal and shoal formation due to siltation in dry seasons hindered barge movements,” said Mishra.

Engineering marvel

The hard work has paid off and Misra is satisfied that the project team has given the iconic MG Setu a new lease of life. The MG Setu will go into history books as India’s longest steel bridge and the first balanced cantilever bridge to be converted into a simply supported bridge.

  • 1st bridge in India whose substructure is retained & superstructure replaced by steel deck
  • Eastern flank (downstream side bridge) completed & handed over for traffic in 18 months
  • Erection of superstructure completed in 13 months, 50 pier caps modified & cast in 11 months

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