大跨度CFST拱桥行波效应的地震反应分析

Seismic Response Analysis of Long Span CFST Arch Bridge Under the Action of Travelling Waves

介绍了模拟地震反应地面运动的大质量法,并用大质量法和拱脚固定法在有限元软件ANSYS里对大跨度钢管混凝土(CFST)拱桥地震反应进行分析:用大质量法对大跨度CFST拱桥进行考虑行波效应的地震反应分析,用拱脚固定法证明该法的准确性,并应用到南宁市一座正在施工的跨径为346 m CFST拱桥中.通过分析得出了两种方法的结果是一致的,内力和位移的值相差不到0.2%,考虑行波效应时,相位差为0.6 s到1.5 s时最关键,主要截面内力和位移增大2～3倍,扭矩除L/4截面外均较小.

Large-mass method of simulating the motion of ground is introduced, and this method and the arch root fastness method are applied to analyze the seismic response of long span CFST arch bridge in ANSYS. The large-mass method is applied to analyze the seismic response of long span CFST arch bridge under the aetion of traveling waves, in which the preciseness is testified by the arch root fastness method. All these are applied to analyze a CFST arch bridge of 346 meters under construction in nanning, from which some significant conclusions are made. The analyses show that the results of two methods are uniform, and the differences of internal forces and displacements are less than 0.2 percent. Under the action of traveling waves, it is most important when phase difference ranges from 0.6 s to 1.5 s because the internal forces and displacements of main sections are more than 2 - 3 times. Torsion moments are small with the exception of the L/4 section.