Evaluation of performance of J P Setu, 2nd longest rail-road bridge over river Ganga at Patna and formulation of damage mitigation strategies based on dynamic response measurements using comprehensive instrumentation and field investigations
Jai Prakash Narayan Setu Bridge (JP Setu, Br No.7) across river Ganga at Patna is the second longest rail-road bridge which was commissioned to service in the year 2016. However, the bridge started showing distress in some of the joints and the pot bearing supports over the period of service. East Central Railway has entrusted CSIR-SERC for complete investigation on few typical spans of the bridge through instrumentation, dynamic testing and numerical simulation studies to study on the cause of distress and for retrofitting of the bridge. The total length of the bridge is around 4.5km having 36 numbers of 123m spans of simply supported through truss girders having rail at the bottom deck level and roadway at the top deck. Three numbers of typical spans of the bridge were identified for investigation, and comprehensive instrumentation scheme for measuring the deflection, strains on various members, vibration and rotation of the supporting pot bearing was formulated. The bridge spans were completely instrumented and tested with two fully loaded complete test train formations for various static and dynamic test case scenarios in single and opposite direction of running trains. This type of testing is first time adopted to get the complete understanding of the bridge behaviour under operating train running conditions. Exhaustive numerical simulation studies were carried out simulating the dynamic test running cases of the train formations using vehicle-track-bridge interaction models. Based on the investigations carried out, report will be submitted to ECR detailing on the investigations carried out, distress assessment, and retrofitting strategies to be adopted for briging the bridge to its full service stage conditions of designed loading and speeds.
JP Setu Rail-Road Bridge across River Ganga, Patna
Twin test train formations used for dynamic testing with simultaneous running of trains
Typical bridge responses obtained from the sensors instrumented on the bridge members