营口辽河公路大桥抗震性能研究

Research on Earthquake Resistance Performance of Liaohe River Highway Bridge in Yingkou

以营口辽河公路大桥为背景,对斜拉桥的抗震性能进行研究。从斜拉桥的抗震分析方法和动力分析模型入手,研究斜拉桥的结构动力特性,用斜拉桥地震响应的反应谱法和时程积分法分析计算。动力特性分析结果表明初始索力和重力对结构的动力特性的计算结果影响很小。对于大跨度斜拉桥至少取前30个振型进行反应谱分析才合理。在3个方向的地震作用下,采用反应谱法计算,斜拉索的地震力较小,静内力加动内力均小于索的设计值,索始终保持弹性工作,且无松弛现象。以全飘体系顺桥向+竖向输入地震波进行时程分析,计算出塔根部支座反力、辅助墩及边墩支座反力、节点位移最值、拉索单元轴力最大值,并绘出顺桥向和竖向EL-centro地震波时间历程曲线图。

By Taking Liaohe River Highway Bridge in Yingkou as the background,the earthquake resistance performance of cable-stayed bridges was analysed.Based on antiseismic analytical method and dynamic analytic model,the structural dynamic characteristics of cable-stayed bridge were studied by using response spectrum method and time history integration method.The analytical result shows that(1)initial cable force and gravity have little effect on the evaluation of the structural dynamic characteristics;(2) the first 30 vibration modes should be analysed at least with response spectrum method for long-span cable-stayed bridge;(3) under earthquake action in three directions,the earthquake force of cable is small and the static/dynamic internal forces are smaller than the designed values of cable based on response spectrum method,which enable the cable always keeps elasticity without slack.By means of time history analysis of lengthways and vertical earthquake wave input in full floating system,the support reactions of foundation,auxiliary pier and side pier,the maximum and minimum of nodal displacement,the maximum of axial force were calculated and draws the time history curve of lengthways and vertical EL-centro earthquake wave input were drawn.