Abstract

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Title:: Effects of Wave Velocities on Seismic Response of Cable-stayed Bridge Under Asynchronous Excitation

Author(s):: ZHANG Fan; YAN Xiao-wei; LI Shuai; WANG Jing-quan; Key Laboratory of Concrete and Prestressed Concrete Structures, Ministry of Education, Southeast University

Keywords:: bridge engineering; relative motion method; long-span cable-stayed bridge; wave-passage effect; multi-support excitation; apparent wave velocity

Abstract:: In order to investigate the effects of propagation velocity of ground motions on the seismic response of cable-stayed bridge, a cable-stayed bridge with span length of 406 m was taken as an example and the dynamic finite element model was built. The multi-support excitation method was analyzed theoretically, and the characteristics of the relative motion method, the large mass method and the large stiffness method were compared. When the current wave velocity is infinity, the calculation results under asynchronous excitation were compared with those under uniform excitations to verify the accuracy of the method of ground input. On this basis, considering the different characteristics of ground motions in soft soil area and rock area, Tianjin wave, El Centro wave and Wenchuan wave were chosen with different propagation velocities ranging from 50 m·s-^1??to 4 000 m·s^-1?.The results show that different velocities have significant influence on seismic response of cablestayed bridge, and the influence of apparent wave velocity on structure is more prominent in soft soil area. The internal force and displacement should be considered when long-span cable-stayed bridge in deep soft soil area is analyzed, while the internal force will be only concerned in rock area.