Study on Seismic Response Mechanism of Continuous Rigid Frame Composite Girder Bridge of High-Speed Rail

Abstract

AbstractIn order to explore the earthquake response mechanism of continuous rigid frame composite girder bridge of high-speed railway, based on a rigid frame bridge of high-speed railway in northwest China and combined with the characteristics of CRTS type I double block non-ballast track structure, three continuous rigid frame composite girder bridge models were established, which considered the constraints of track and subsequent structure, only considering the constraints of track and no considering the constraints of track. The seismic response of structural systems is studied by using response spectrum method. The results show that the track constraint effect reduces the natural vibration period of the structure, and the subsequent structure has a inhibition effect on the seismic response of the track system, which is 4.18%. At the top beam joint of the transition pier, the change of pier height has a significant effect on the seismic response of the track. With the increase of pier height, the maximum rail stress of model 1 and model 2 increases by 50% and 65%, respectively. Under the constraint of track, when the height of rigid frame pier is 28% different from that of simple beam pier, the seismic internal forces of the two piers are equal. When the height of rigid frame pier is greater than 28%, the transition pier is the main energy-consuming rod, and when the height of rigid frame pier is less than 28%, the rigid frame pier is the main energy-consuming rod. Therefore, for bridge types with different pier heights, corresponding design reinforcement measures should be taken at the bottom of the transition pier and rigid frame pier respectively.