Vehicle response is served as a reference to evaluate riding comfort of passengers and running safety of moving carriages for high speed trains. In analyzing the vehicle-bridge interaction (VBI) problems, two sets of coupled equations of motion for running vehicles and bridge need to be solved and the VBI system matrices must be updated and factorized at each time step in a time-history analysis. This paper proposed a quasi-VBI model to abridge the complicated computational process, in which the bridge is subjected to only moving static forces of the train loadings, and the moving vehicle over it is excited by the corresponding feedback bridge response. To examine the interacting degree of the vehicle with the bridge, a coupling evaluation index (CEI) is defined as a quantitative assessment of the VBI system. The numerical parametric studies reveal that (1) the mass ratio of vehicle to bridge is the most sensitive parameter affecting the bridge response; (2) increasing bridge damping can reduce the coupling degree of the VBI system at high speeds; (3) the present quasi-VBI model is an efficient and simple tool to predict the vehicle's response with enough accuracy based on engineering approximation.

This paper is focused on the vibration in a two‐hinged arch bridge subjected to the combined action of moving loads and vertical ground excitations. The arch bridge is modeled as a flat‐rise parabolic arch with constant sectional properties along the horizontal axis of span, and the train loadings over it as a sequence of identical lumped loads with constant intervals. To investigate such a dynamic problem, a single span bridge with non‐homogeneous time‐dependent boundary conditions, the quasi‐static decomposition method is employed to decompose the deflection response of the arch into quasi‐static deflection and the dynamic component of deformation. Then one can analytically derive the closed form solution of quasi‐static deflection for the arch bridge shaken by vertical support excitations. Throughout the parameter studies, the present results indicate that the maximum acceleration response on the arch bridge relates to: (1) the vibration mode that has been excited, (2) the time lag until moving loads begin to enter the bridge during the acting time of earthquakes, and (3) the rise to span ratio of the arch.

As a seismic wave travels along the separate supports of an extended structure, the structure is subjected to multiple-support excitation due to seismic wave propagation. Considering the seismic wave passage effect, this paper describes seismic analysis of a maglev vehicle moving on a multiply supported gudieway. The guideway system is modeled as a series of simple beams and the vehicle as a four degrees-of-freedom (DOFs) rigid bar equipped with multiple onboard PI+LQR hybrid controllers. The controller is used to regulate control voltage for tuning both magnetic forces of uplift levitation and lateral guidance in the maglev system. Numerical studies show that as a maglev vehicle is equipped with more supported magnets then they can provide more control gains for tuning the guidance forces of the moving vehicle, and mitigate seismic-induced lateral vibration of a maglev vehicle running a guideway.