移动均布荷载作用下弹性支撑简支梁动力系数变化规律研究  

DYNAMIC FACTORS OF SIMPLE BEAM ON ELASTIC SUPPORT UNDER UNIFORMLY DISTRIBUTED MOVING LOAD

作　　者：宋晓东[1] 吴定俊[1] 李奇[1] 

机构地区：[1]同济大学桥梁工程系,上海200092

出　　处：《工程力学》2013年第4期281-287,共7页Engineering Mechanics

摘　　要：将双塔斜拉桥主跨简化为均布弹性支承的简支梁,采用模态叠加法求解其在高速磁浮列车荷载作用下动力响应的解析解。根据该简化模型计算的跨中动力系数与双塔斜拉桥动力系数变化规律具有较高的一致性。桥梁跨中动力系数仅与基频比、车桥长度比和弹性支承影响系数这3个无量纲参数有关,计算跨中位移动力系数随这3个参数的变化规律并绘制等值线图,以快速获取动力系数。在给定最高车速下,为将动力系数控制在一定限值以内,给出了不同跨径双塔斜拉桥的竖向基频下限值。Double-tower cable-stayed bridges are simplified as simply supported bridges with a uniform elastic support to obtain the analytical solutions of bridge responses under moving maglev trains.The dynamic factors of mid-span displacements obtained from the analytical models agree well with those from the numerical models of the cable-stayed bridges using the finite element method.The analytical solutions also reveal that the dynamic factors mainly depend on three dimensionless coefficients,i.e.,the fundamental frequency ratio,the train-bridge-length ratio and the elastic support influence coefficient.Contour maps on the basis of these dimensionless coefficients are proposed to attain the dynamic factors of double-tower cable-stayed bridges without complicated calculation.The lower-limits of fundamental frequencies for the cable-stayed bridges of different spans are presented in order to control the dynamic factors of the bridge below reasonable values.

关 键 词：移动均布荷载 弹性支承 高速磁浮列车 双塔斜拉桥 动力系数 频率限值 

分 类 号：U237[交通运输工程—道路与铁道工程] U448.27[建筑科学—桥梁与隧道工程]