箱形梁剪滞效应分析的一维有限元法及其应用  

One-dimensional finite element method and its application for the analysis of shear lag effect in box girders

作　　者：张元海[1] 王来林 李乔[3] 

机构地区：[1]兰州交通大学,甘肃兰州730070 [2]兰州建设工程交易中心,甘肃兰州730030 [3]西南交通大学,四川成都610031

出　　处：《土木工程学报》2010年第8期44-50,共7页China Civil Engineering Journal

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资助项目(3ZS042-B25-032)

摘　　要：为了分析变截面箱梁及特殊支承连续箱梁等复杂结构的剪滞效应,在引入剪滞广义力矩及翘曲几何特性的基础上,提出一种改进的梁段有限元法。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,推导箱梁剪滞效应分析的梁段单元刚度矩阵和等效节点力向量的具体表达式,并导出用单元节点力直接计算应力的一般公式。用FORTRAN语言编制箱梁剪滞效应分析的一维有限元电算程序BGAS,对三个有机玻璃箱梁模型进行计算并与实测值比较。结果表明,所提出的梁段单元用于分析复杂箱梁的剪滞效应是可靠的;在竖向荷载作用下,各种箱梁的剪滞力矩与弯矩具有相似的分布规律,而且数值大小也基本接近。On the basis of the generalized moment and warping geometrical properties for shear lag,a refined finite segment method is proposed to analyze the shear lag effect in complex box girders with variable cross-section and special supports.The homogeneous solution of the governing differential equation is taken as the displacement function of the finite element.The formulas of the element stiffness matrix and equivalent nodal force vector are established by taking the constants of integration as conversion variables.A general formula for the stress calculation is presented in which the element nodal forces are employed.A finite element program BGAS for shear lag analysis of box girders is developed using FORTRAN language and is employed to calculate three plexiglass models of box girders.The calculated and measured values are compared.It is shown that the present element is reliable in analyzing the shear lag effect of complex box girders.The shear lag moment and bending moment for all kinds of box girders are similar in distribution and value under vertical load.

关 键 词：薄壁箱梁 剪滞效应 一维有限元 广义力矩 双室箱梁 

分 类 号：U448.213[建筑科学—桥梁与隧道工程]