考虑桩土相互作用的大跨度钢拱桥地震反应分析  

Influence of soil-pile interaction on the seismic response analysis of a large-span steel arch bridge

作　　者：宋波[1] 刘泉[1] 李凡凡[1] 周宏宇[2] 

机构地区：[1]北京科技大学土木与环境工程学院,北京100083 [2]北京工业大学工程抗震与结构诊治北京市重点实验室,北京100022

出　　处：《北京科技大学学报》2009年第9期1077-1085,1105,共10页Journal of University of Science and Technology Beijing

基　　金：国家自然科学基金重大研究计划"重大工程的动力灾变"资助项目(No.90715007)

摘　　要：为了研究桩土相互作用下大跨度钢拱桥的地震反应特点以及塑性铰的形成部位和发展过程,利用ANSYS有限元程序对比研究了在多组地震输入条件下,考虑基础固结和桩土相互作用下的动力特性及在罕遇地震下的地震反应,并探讨了层状场地土对桩基以及上部结构的影响.结果表明:与基础固结模型相比,考虑桩土相互作用体现了土的特性对结构的影响,较好地反映了结构的动力特性,结构的自振周期延长,且对高阶振型周期影响显著;同时结构各部位的内力响应呈下降趋势,位移响应被放大,但受边界假定的影响,其总体反应趋势未发生改变,其中在主梁1/4处、梁拱结合处以及柱底处均出现塑性铰,且柱底处率先屈服,各塑性铰区的变形仍控制在较小的范围内,桩身则未出现塑性铰.In order to study the earthquake response characteristics of a long-span steel arch bridge and the formation position and development process of plastic hinges in the bridge under soil-pile interaction,Ansys FEM software was used to comparatively discuss the effects of layered soil on the pile foundation and upper structure in consideration of structural dynamic characteristics and earthquake response under two different boundary conditions at the bottom of the bridge,i.e.,foundation consolidation and pile-soil inter-action. The results showed that the soil-pile interaction model reflected the effect of soil characteristics on the structure and it could better reveal the structural dynamic characteristics compared with the consolidation model. Using this model, the natural vibration period of structure was protracted, the period of high-order vibration modes varied significantly, and the internal force response of every part was declined, while the displacement response was amplified. But considering the effect of boundary conditions, the general trend did not change. The plastic hinges emerged on one fourth of the main girders, the girder-arch joint parts and the bottom of piers, the bottom of piers yielded firstly, while the deformation of plastic-hinge zones was still controlled in a smaller range, and the plastic hinge did not emerge on the piles.

关 键 词：钢拱桥 大跨度 地震响应分析 桩土相互作用 塑性铰 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]