考虑剪滞变形时箱形梁广义力矩的数值分析  

NUMERICAL ANALYSIS OF GENERALIZED MOMENT IN BOX GIRDER CONSIDERING SHEAR LAG DEFORMATION

作　　者：张元海[1] 李乔[2] 

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]西南交通大学土木工程学院,四川成都610031

出　　处：《工程力学》2010年第4期30-36,共7页Engineering Mechanics

基　　金：甘肃省高等学校研究生导师科研项目(0804-09);甘肃省自然科学基金项目(3ZS042-B25-032);兰州交通大学"青蓝"人才工程基金项目(QL2004-2A16)

摘　　要：为了简化变截面箱梁等复杂结构的剪滞效应分析,在明确定义相应于剪滞位移的广义力矩和有关几何特性的基础上,提出一种梁段有限元数值分析方法。选取控制微分方程的齐次解作为单元位移函数,以各积分常数为中间转换变量,推导梁段单元刚度矩阵和等效节点力向量的具体表达式,并给出用单元节点力直接计算应力的一般公式。编制了箱梁梁段有限元程序,对简支、悬臂、连续箱梁3个有机玻璃模型进行计算并与实测结果对比,验证了该文方法及公式的正确性。用所编程序对箱梁的剪滞广义力矩进行数值分析,并揭示了其变化规律。研究表明,在竖向荷载作用下,剪滞力矩与弯矩具有相似的分布规律,而且数值大小也接近。The paper defines the concept of generalized moment corresponding to the shear lag displacement and the relevant geometrical properties, then a finite segment element method is proposed to simplify the shear lag analysis in complex box girder with varied cross-section. The homogeneous solution of the governing differential equation for the shear lag analysis is adopted as the displacement function. The formulas of the element stiffness matrix and equivalent nodal forces are obtained by taking the constants of integration as conversion variables. The general formula for stress is presented in which the element nodal forces are employed. The finite segment element program is developed and is used to analyze simply supported, cantilever, and continuous plexiglass box girder models. The theoretical results are in good agreement with the experimental results. The generalized moment for shear lag is numerically analyzed, which is similar to bending moment in distribution and magnitude under vertical load.

关 键 词：薄壁箱梁 剪滞效应 梁段有限元 广义力矩 剪滞力矩 

分 类 号：U448.213[建筑科学—桥梁与隧道工程]