摘要
Abstract
Because of the large distance between supports of the long-span cable-stayed bridge ( LSCSB) and the limited propagation speed of the seismic wave, there exists some time difference when the seismic wave reaches the supports. As a result, the analysis method of uniform excitation cannot meet the actual situation. Thus, a long-span cable-strayed bridge with 680 m main span is taken for calculation and a finite element model is established to analyze the seismic response of the main girder and the towers with traveling wave effects under one-dimensional and multi-dimensional random seismic excitations. And a comparative analysis between uniform earthquake excitations and non-uniform earthquake excitations is conducted. The results show that compared to uniform excitations, longitudinal displacements of the middle span decrease 42. 3% and 44. 8% and the vertical bottom moments of No. 1 tower and No. 2 tower decrease 25. 9%, 19. 9%, and 0. 4%, 1. 2%respectively under longitudinal earthquake excitations when wave velocity is 200 m/s and 300 m/s. Structural response under multi-dimensional earthquake excitations is larger than that under one-dimensional earthquake excitations. Therefore, effects of dimensionality of earthquake motions and traveling wave should be fully considered in the seismic analysis for LSCSB.关键词
大跨度斜拉桥/随机响应/行波效应/多维输入/功率谱密度Key words
Long-span cable-stayed bridge/Stochastic response/Traveling wave effect/Multi-dimensional excitation/Power spectral density分类
交通工程
