对于高烈度地震区的公路不等高桥墩简支梁桥,在采用隔震橡胶支座进行隔震设计时,应考虑由桥墩高度差引起的桥梁不规则性,从而合理选用支座参数及其布置墩位.针对一5跨不等高简支梁桥选择4种支座,共考虑了31种支座布置工况,利用ANSYS软件对全桥建立了简化的力学数值计算模型,并采用非线性时程法分析了简支梁桥在地震作用下的动态响应.分析结果表明:不同的支座布置方式会影响桥梁结构的动力特性、桥墩底部的弯矩、剪力及墩顶位移;建议采用墩底弯矩和剪力的减震率总和来判断各支座布置工况的隔震效果,达到对支座布置进行优化的目的,进而提高全桥的整体隔震水平.%According to a highway simple supported girder bridge with unequal high piers in high intensity earthquake area,in order to reasonably select the support parameters and layout the piers, the bridge irregularity caused by the difference of pier height should be taken into account in the design of seismic isolation rubber bearings. In view of a five spans unequal height simply supported girder bridge, four bearings were selected and thirty-one kinds of support arrangement conditions were taken into account.A simplified mechanical model of the whole bridge was established by using ANSYS software.The dynamic response of simply supported girder bridge under earthquake action was analyzed by using the nonlinear time history method.The analysis results indicate that the different bearing arrangement will affect the dynamic characteristics of the bridge structure,the bending moment and shear of the pier bottom,the displacement of the pier top.It is suggested to adopt the sum of seismic-reduction rate of bending moment and shear at the pier bottom to determine the isolation effect of the bearing arrangement condition,so as to optimize the bearing arrangement and improve the overall seismic isolation level of the whole bridge.
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