Seismic response of track system on continuous bridge under complex bridge structure arrangements

In order to investigate the seismic characteristics under complex structure arrangements of beam-bridge system, a nonlinear constrained finite element model of bridge-rail system was established by using the seismic impact mass method to analyze the stress of CWR on continuous bridge under earthquake impact, the influence of the structure layout of key design parameters, such as the longitudinal resistance of the line, the number of adjacent simply supported bridges and the non-sequential layout of bearings on the seismic response of the structure, were studied. The findings show that when it is difficult to check the strength of the rail on the large-span continuous bridge, it is necessary to adopt the small resistance fastener scheme. It is recommended to lay small resistance fasteners only in the continuous bridge range under the influence of earthquake to keep the stress and displacement of the structure within a small limit. The rail expansion adjuster is a weak link in CWR, which would cause track irregularity. The use of the steel rail expansion adjuster shall be minimized. If necessary, it is recommended to set it only at the movable end of the continuous bridge. If still not satisfied, small resistance fasteners can be laid at the same time on the opposite side span and the adjacent span simply supported bridge. During seismic analysis, simplified calculation of seismic action can be carried out by connecting 8-span simply supported bridges on both sides of the continuous bridge. As the span of the continuous bridge increases, the stress on the rail increases significantly, and the falling probability of the adjacent simply supported bridge increases. When the abutment subgrade is well filled, the fixed bearings of adjacent simply supported bridges can be arranged close to the continuous bridges to balance the stress and deformation by reducing the temperature span. When the quality of the abutment subgrade is poor, the movable bearing of simply supported bridge can be set at the abutment to greatly reduce the stress on the abutment. © 2023, Central South University Press. All rights reserved.