First bridge in India whose substructure is retained, and the superstructure is replaced by steel deck superstructure A fully renovated and operational Mahatma Gandhi Setu (MG Setu) will be available for traffic after the eastern flank of the bridge has been inaugurated on June 7. The 39-year-old Gandhi Setu over river Ganga will become the longest steel bridge in the country with a length of approximately 5.6 km. The Gandhi Setu is the first balanced cantilever bridge in the country which has been dismantled and converted into a simply supported bridge. The existing concrete substructure is retained, and the superstructure has been replaced by steel deck superstructure. The bridge rehabilitation works began in 2017 and the western flank was inaugurated in 2020. It is nothing short of remarkable that a complex bridge rehabilitation project of this scale is completed in five years. Reminiscing the journey, SK Misra, Afcons Project Manager, has said, “Earlier there used to be a waiting period of three to four 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 100,000 passenger vehicles cross this bridge every day. The bridge is vital to the state’s socio-economic development because it connects north and south Bihar. “We completed the entire downstream lane (eastern flank) in 18 months and various factors helped to speed up the construction works. There were lessons learnt when we were working on the upstream side (western flank). Fabrication of trusses for the downstream side was done in advance. We improvised and innovated our dismantling methodologies such as use of holding frame for wet spans. We worked in parallel on pier modification and truss erection,” Misra has added. The biggest concern in the project was the running traffic on the adjacent bridge at all times. “On 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. Almost 66,360 metric tonne steel has been used for the entire bridge superstructure. Elaborating on this massive volume of steel usage the Project Manager has 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 Gandhi Setu too. “During the monsoons, we had to navigate up to 7 m of water level rise and high currents in the river zone. Flooding was normal and shoal formation due to sedimentation in dry seasons hindered barge movements.” All the hard work has paid off and Misra is satisfied that the project team has given the iconic Gandhi Setu a new lease of life. The Gandhi 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. Key Takeways: Eastern flank (downstream side bridge) completed and handed over for traffic opening in 18 months. Erection of steel superstructure completed in 13 months. 50 pier caps modified and cast in 11 months. Bridge dismantling activities completed in 8 months.