基于土-结构相互作用的隔震连续梁桥的地震响应

以典型三跨隔震连续梁桥为工程背景,采用Bouc-Wen滞回恢复力模型,模拟LRB（lead rubber bearings）的力-位移非线性特性,建立了考虑土-结构相互作用的多质点系集中质量有限元计算模型,编制了运用Wilson-θ逐步积分法求解增量形式的土-结构体系非线性运动方程的时程分析程序.利用程序并结合算例分别对考虑土-结构相互作用与按照墩底固结假设的两种桥梁模型进行了隔震前后的时程对比分析.结果表明：在Ⅰ、Ⅱ类场地土上,考虑土-结构相互作用与按照墩底固结假设相比,前者得到的地震响应峰值较大,但峰值相差不大.Ⅲ类场地上,前者的地震响应峰值比后者大得多,不能忽略土-结构相互作用的影响;在同一场地类型下,隔震率对是否考虑土-结构相互作用并不敏感,但Ⅰ、Ⅱ类场地上的隔震效果要明显优于Ⅲ类场地.

Seismic response of isolated continuous girder bridges based on soil-pile-bridges interaction

Taking the three spans isolated mntinuous girder bridges for the engineering background, Bout-Wen restoring force model is adopted to simulate the nonlinear characteristics for LRB, multi-story liner system ocrn- centrated quality finite dement analytic model mnsidering SSI is established, and the time-history analysis pro- cedure of the Wilson- θ step-by-step integration method used to solve the increment form nonlinear governing equation of motion oonsidering SSI is programmed. We make a mntrastive analysis based on before and after isolated bridges model of oonsidering SSI and rigid foundation hypotheses by combining the procedure with cal- culation example. The results indicate that the considering SSI has larger value on the seismic response than the rigid foundation, but the seismic response value has no great difference between two models under pulse of type I and 11. The considering SSI has larger value on the seismic response than the rigid foundation under pulse of type Ⅲ, so the SSI can not be neglected in the isolated seismic design of bridges under pulse of type Ⅲ. The LRB isolated rate has insensitive to considering SSI or not, and LRB isolated rate has no great difference be- tween two models under the same type of pulse, but the effect of LRB under pulse of type Ⅰ and Ⅱ is superior to effect of LRB under pulse of type Ⅲ.