薄壁曲线箱梁材料非线性分析的内力塑性系数法

The Internal Force Plastics Coefficient Method for Material Nonlinear Analysis of Thin-Walled Curved Box Girders

目的研究薄壁曲线箱梁考虑剪力滞效应和材料非线性的计算方法.方法基于势能变分原理,推导了薄壁曲线箱梁的刚度方程.采用变刚度初法应力法,并结合截面内力塑性系数修正刚度系数,对薄壁曲线箱梁的材料非线性问题进行了求解.结果通过算例计算,得到了曲线箱梁顶底板的应力分布以及挠度和扭转角的变化曲线.结论笔者的计算结果与试验值整体吻合较好.对于薄壁曲线箱梁,悬臂板、顶板和底板,分别取三个不同的剪力滞翘曲位移函数的结果,精度优于三者取一个统一的剪力滞翘曲位移函数;随荷载的增加,弯曲剪力滞效应系数较挠度和扭转角更早进入非线性状态,翼缘截面上的应力分布逐渐趋于均匀,上翼缘应力的这种变化趋势要略滞后于下翼缘,而中支座截面翼缘应力的这种变化趋势则略快于左跨跨中和右跨跨中截面.

This paper is to study the computing method for thin-walled curved box girder in considering shear lag and material nonlinearity. The stiffness equation of thin-walled curved box girders was deduced by mean of potential variational principles. According to the various-stiffness initial-stress method and section internal force plastics coefficient to amend stiffness coefficients, the material nonlinear question of the structure was solved. It is shown that the calculation results of the authors agree with those of the test; the results for taking three different shear lag warpage displacement functions to cantilever, top and bottom plates are more accura- cy than those for taking one shear lag warpage displacement function;with the increase of loads, moment shear lag effect coefficients will enter into nonlinear state earlier than the deflection and the torsional angle; the stress distribution on flange of the cross section becomes more and more uniform; this trend of stresses on the top flange lags behind the bottom flange a little, while this trend on the middle support section is slightly faster than the cross section in the middle of the left span and the fight span.