铅芯橡胶支座隔震桥双向地震响应影响因素研究

考虑铅芯橡胶支座双向耦合作用更能模拟LRB隔震桥在地震波作用下的实际响应。文章以一座典型三跨连续梁桥为工程背景，通过对结构的离散建立包含铅芯橡胶支座出力的全桥有限元分析模型，采用Bouc—wen模型模拟LRB的非线性双向耦合特性，采用增量形式的Newmark方法和龙格库塔法联合求解非线性动力方程。通过比较在不同的桥梁结构几何参数和支座参数下的地震响应来研究这些参数对双向隔震桥地震响应的影响。数值结果表明，桥墩刚度和支座初始刚度、硬化比和屈服强度对LRB隔震桥响应影响很大，在进行隔震设计时，必须对以上参数进行优化设计，选择最合理的参数，使地震响应降到最低。

Effects of Factors on the Bi-direction Seismic Response of LRB Isolated Bridge

The seismic response of the LRB isolated bridge under the bi-direction earthquake motions can more accurately simulated considerate bidirectional couple action of the LRB .The selected bridges is a typical three spans continuous deck supported on the LRB. The finite element analytic model which involved the force contribution of the lead rubber bearings is established by make the structure discrete. Bouc-wen model can be used to simulate the nonlinear dynamic behavior of the force-displacement relationship for LRB, both the increment form Newmark and the Runge-Kutta iterative strategy are used to solve the nonlinear governing equation of motion. The seismic response of different bridge parameter and bearings parameter for bridges isolated by lead rubber bearing （LRB） is investigated under two horizontal components of real earthquake ground motions. The effect is investigated by comparing their response under different parameters. The consequences indicate that the pir stiffness and the initial stiffness and the hardened rate and the yield stress of the LRB have large effect on the seismic response of isolated bridge, when we do a earthquake-resistance design, the parameter optimum design must be completed so that the best value can be selected and the seismic response of the isolated bridge is the minimum.