Control of Difference of Seismic Response across Different Spans of high-speed railway multi-spans simply supported bridge

Abstract

In this paper, the Difference of Seismic Response across Different Spans (DSR) in the longitudinal distribution of High-Speed Railway Multi-spans Simply Supported Bridge (HSRSB) under longitudinal earthquake excitation is investigated, and an evaluation method which can intuitively reflect the difference of seismic response is proposed. A feasible way to strengthen the connection stiffness between adjacent girders is proposed to control DSR. The rationality of the finite element model used is verified by comparing the numerical results with the experimental ones, showing a satisfactory agreement. Comparing the seismic response of a bridge model considering the subgrade-track constraints (BCTM) and a bridge model without subgrade-track constraints (BWTM), it is found that the DSR in the longitudinal distribution causes some new disadvantages, which are neglected in BWTM. The BCTM considering DLC generates a model called BCDM. The effect of the number of span on DSR are studied based on BCDM. The analysis of this model showed that DLC suppresses the DSR and reduces the seismic response of most bridge components. It also transfers the seismic disadvantage from the bridge part to the subgrade-track structure. As it is more convenient and cost-effective to repair the base plate of the subgrade than the bridge components after earthquake seismic event, this disadvantage transfer is in favor of forming a new anti-seismic system that subgrade-track structure is used to protect the bridge part.

Design seismic track irregularity for high‐speed railways

“…The transverse motion of high-speed railway bridge structure is restricted by subgrade and track structure. [24][25][26] The restriction decreases as the bridge mileage increases, therefore the shape of seismic track irregularity is typically larger in the middle and smaller on both sides. 11,13 Yu et al built a non-stationary time-domain model of design seismic track irregularity utilizing evolutionary power spectral density technique and fit the time-domain model utilizing multiple key points.…”

“…has certain limitations because the power spectral density technique is based on Fourier transform and is a stationary signal processing technique, 22,23 whereas seismic track irregularity clearly demonstrates non‐stationary properties. The transverse motion of high‐speed railway bridge structure is restricted by subgrade and track structure 24–26 . The restriction decreases as the bridge mileage increases, therefore the shape of seismic track irregularity is typically larger in the middle and smaller on both sides 11,13 …”