Y多点激励下钢管混凝土组合桁架连续梁桥的地震响应分析.docx

河谷场地中钢管混凝土空间组合桁架连续梁桥地震响应分析王海良，王世广，刘中宪，黄磊(天津城建大学土木工程学院，天津 300384)摘 要：地震观测表明：河谷场地对大跨桥梁地震响应影响显著。京昆高速公路“干海子特大桥”位于河谷场地，下部结构主要为钢管混凝土格构墩（最高110m），上部结构为钢管混凝土空间组合桁架连续梁（最长联1044m）。以该桥为工程背景，建立其三维有限元动力计算模型，通过多点激励(改进LMM法)方式进行地震动输入，研究行波效应、局部场地效应对其地震响应影响，并和一致激励进行比较,结果表明：该类桥梁低墩较高柔桥墩对地震动更敏感；较一致激励，墩、梁刚接桥墩和梁跨，行波效应增大其墩底轴力、跨中下弦杆和斜腹杆轴力,但减小其它量测值；墩、梁间设支座桥墩和梁跨，行波效应减小其墩底弯矩、墩顶位移和跨中位移；较一致激励、行波效应，局部场地效应显著增大了大多桥墩、梁跨的内力和位移，同时所考察各类内力和位移较一致激励的最大增幅均在150%以上，且对布置在河谷坡面及邻近区域墩、梁的影响最为明显。实际河谷场地中该类桥梁抗震设计需充分考虑局部场地效应。关键词：钢管混凝土格构桥墩；钢管混凝土空间组合桁架连续梁桥；多点激励；行波效应；局部场地效应中图分类号： 文献标志码： Seismic Response analysis of the CFST AND space COMPOSITE trussED continuous bridge located in the valley SITEWANG Hai-liang, WANG Shi-guang, LIU Zhong-xian, HUANG Lei(School of Civil Engineering, Tianjin ChengJian University, Tianjin 300384, China )Abstract: Seismic?observations show that: valley site has significant?influence?seismic on the response?of?long-span bridge. Ganhaizi Bridge of Beijing Kunming Expressway is located in?valleys site. The piers mainly adopt concrete-filled steel tubular(CFST) lattice pier(the highest is 110m) and the girders adopt the CFST and space composite trussed continuous beam(the longest is 1044m). Based on this bridge project, the FEM model of whole bridge is established. The multi-point ground motion excitation is considered improved LMM for studying on the traveling wave effect and the local site effect, comparing with the?uniform excitation. The results indicate that the low piers on the ground is more sensitive than the high piers; For the rigid piers and beams, comparing with the?uniform excitation, traveling wave effect increases the axial force at bottom of pier, the axial force of lower chord and of oblique abdominal rod in mid-span but reduce the other measurements. For the piers and beams with the support, comparing with the?uniform excitation, traveling wave effect reduce the moments at bottom of pier, the displacement at top of pier and the displacement in mid-span; Comparing with the?unifo