移动均布荷载作用下简支梁桥动力系数分析  

IMPACT FACTOR ANALYSIS OF SIMPLY-SUPPORTED GIRDER BRIDGES TRAVERSED BY UNIFORMLY-DISTRIBUTED MOVING LOADS

作　　者：邓建良[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5期56-62,共7页Engineering Mechanics

基　　金：高等学校博士学科点专攻科研基金项目(20090072110044)

摘　　要：将磁悬浮列车荷载简化为移动均布荷载,运用模态叠加法求解得到了简支轨道梁的动力响应解析解,并与相应的数值解和列车-桥梁耦合振动解作了比较,指出移动均布荷载模型可以反映轨道梁振动的主要特征和振动规律。从理论上揭示出决定动力系数大小的关键无量纲参数,并分析了动力系数随各参数的变化规律。最后,提出了可供设计参考的轨道梁设计频率限值和动力放大系数之间关系的图表和数学表达式。The dynamic responses of a simply supported girder bridge under the action of a maglev train are investigated in this paper. The maglev train is assumed to be a uniformly distributed moving line load, and then a closed-form solution for the response of the bridge is achieved by an analytical approach. Comparison of the analytic solutions with the finite element solutions is conducted, which shows that the behavior of the beam can be very well represented using the moving load model. The primary parameters that govern the impact factor of the beam are then identified analytically on the basis of the modal superposition method. The dynamic behavior of the beam, especially the characteristics of the impact factor, is studied in details. A design method is finally proposed to ensure the actual impact factor not exceeding its prescribed allowable value, based on the discussion on the relationship between the impact factor and a non-dimensional parameter.

关 键 词：简支梁桥 动力系数 移动均布荷载 模态叠加 频率限值 

分 类 号：U448.217[建筑科学—桥梁与隧道工程]