Design of Tall Railway Bridges in North Eastern States, India

Northeast Frontier railway (NFR) intends to connect Manipur, Mizoram and Nagaland with rest part of India. The railway lines pass through eastern trail of Himalaya resulting construction of large number of tunnels and bridges. The entire area is under seismic zone V. The heights of the piers vary from 20m to 141m with maximum length of bridges 700m. The configurations of the bridges were finalized taking into consideration of the parameters like span, location of the pier on the hill slope, constructability, maintainability, safety and economy. Multi modal analysis using site specific spectrum, spectrum compatible time history analysis and spatially varying time history analysis was performed to understand the behaviour of the structure under seismic and deformed shape of the continuous rail on the superstructure for safety of the train movement. Wind tunnel analysis was performed to understand the behaviour of bridge under wind force.