Characteristics of seismic response of high-speed railway frame pier-bridge-track system

In order to study the influence of portal pier structure on the force characteristics of the beam-track system under earthquake action, a refined dynamic simulation model of portal pier-bridge-track system was established by using a verified beam-track contact simulation method with a three simply supported beams with length of 32 m on a portal pier of the Hefei—Fuzhou High-speed Railway as an example. The dynamic response characteristics of simply supported beam bridge-track system on portal pier under multi-dimensional seismic action were investigated and the influence of key design parameters such as node connection method and beam stiffness on the system stress characteristics was discussed. The results show that the structural system stiffness is relatively flexible after using portal pier structure. The natural vibration frequency of the system is reduced. During the earthquake, the longitudinal stress envelope of rails on simply supported beam bridges with portal pier structures is rhombic in shape, with the peak stresses occurring near the piers, abutments and bridge spans. The vertical deflection of the rails and the top of the portal pier slightly decreases with the increase of the stiffness of the portal pier beam-column nodes. In view of the disadvantages of rigid nodes that may lead to reduced structural ductility and large residual stresses, it is suggested that beam-column joints of portal pier should adopt semi-rigid connection. © 2023 Central South University of Technology. All rights reserved.