Simplified calculation modeling method of multi-span bridges on high-speed railways under earthquake condition

Abstract

A simplified calculation model for the integration of tracks and bridges of multi-span simply supported beam bridge on high-speed railway is proposed by considering the longitudinal connecting effects of adjoining structure. Using this simplified calculation model, the seismic response of multi-span standard simply supported beam bridges of multiple high-speed railways was calculated and compared with the seismic response using the corresponding full-bridge model. Based on the above calculation results, the simplification efficiency and equivalent stiffness of simplified calculation model was studied. Seven earthquake records were selected for calculation, and the growth rates of seismic responses with the increase of number of spans were analyzed in detail. The analysis results show that the seismic response using the simplified calculation model and corresponding full-bridge model are identical with each other; the simplified calculation model greatly reduces the calculation time and the efficiency of reducing calculation time is up to a maximum of 86%. The order of arrangements of interlayer components such as shear teeth and support significantly affects the equivalent stiffness of adjoining structures. The equivalent stiffness of adjoining structures becomes stable with the increase in the number of spans of simply supported beam in adjoining structures. The adjoining structures has an amplification effect on the seismic response of target structures, and the amplification effect becomes stable with the increase in the number of spans of simply supported beam in adjoining structures. Without considering the restraint effect of adjoining structures, the seismic response of multi-span simply supported beam bridge on high-speed railway becomes unsafe, that is, the result is smaller than that of considering adjoining structures.