Dynamic interaction of bridge–train system under non‐uniform seismic ground motion

Abstract

The probability that an earthquake occurs when a train is running over a bridge in earthquake-prone regions is much higher than before, for high-speed railway lines are rapidly developed to connect major cities worldwide. This paper presents a finite element method-based framework for dynamic analysis of coupled bridge-train systems under non-uniform seismic ground motion, in which rail-wheel interactions and possible separations between wheels and rails are taken into consideration. The governing equations of motion of the coupled bridge-train system are established in an absolute coordinate system. Without considering the decomposition of seismic responses into pseudo-static and inertia-dynamic components, the equations of motion of the coupled system are formed in terms of displacement seismic ground motions. The mode superposition method is applied to the bridge structure to make the problem manageable while the Newmark-method with an iterative computation scheme is used to find the best solution for the problem concerned. Eight high-speed trains running over a multi-span steel truss-arch bridge subject to earthquakes are taken as a case study. The results from the case study demonstrate that the spatial variation of seismic ground motion affects dynamic responses of the bridge-train system. The ignorance of pseudo-static component when using acceleration seismic ground motions as input may underestimate seismic responses of the bridge-train system. The probability of separation between wheels and rails becomes higher with increasing train speed.

Seismic response analysis of an interacting curved bridge–train system under frequent earthquakes

“…Xia et al , examined spatially non‐uniform seismic ground motions and argued that not considering the seismic wave propagation effect leads to unsafe results regarding the vehicle running safety during earthquakes. Du et al , extended the study of Xia et al , , taking into account the possible separations and recontact between the wheel and the rail. The results indicated that the wheel–rail separation time duration increased as the train speed increased, under non‐uniform seismic ground motions.…”

Dynamic vehicle–bridge interaction under simultaneous vertical earthquake excitation

“…They stressed the significant effect of the vertical ground motion component on the stability of the train-rail bridge system. Further studies have been conducted by Matsumoto et al (2004), Xia et al (2006), Tanabe et al (2008Tanabe et al ( , 2011a, Yau (2010) and Du et al (2012). Recently, the two last authors of the present paper proposed a scheme for the seismic response analysis of interacting (horizontally) curved railway bridges and trains (Zeng and Dimitrakopoulos (2016).…”

Research on the Pushover Methodology and the Applications on the Bridge Seismic Performance Improvement Scenarios

“…Because in the beginning, relatively small nonlinear structure, basic present linear structure, load increment can take a few bigger, in order to save computation time, when the load increases gradually, the contribution of initial stress stiffness matrix is more and more big, the tangent stiffness matrix determinant value drops rapidly, element stiffness is falling rapidly, load-deformation curve gradually flatten out. (2) Load incremental method is used to load stability analysis can only calculate the load-displacement curve of general rising period, when the incremental algorithms of to extreme value point and load-displacement curve of the slope to the zero, the tangent stiffness matrix singularity, stiffness matrix determinant is zero, no matter how small the load increment, the structure also cannot bear more load increment, and the displacement is increasing [6].…”