波形钢腹板箱梁畸变应力分析

Stress analysis of box girders with corrugate steel webs under distorsion

在箱梁理论的基础上,根据波形钢腹板箱梁的力学特性,对波形钢腹板箱梁由畸变引起的翘曲正应力进行了研究.考虑到波形钢腹板具有褶皱效应,把波形钢腹板看作正交异性板,利用波形钢腹板箱梁中各板元平面力系的平衡关系,推导出波形钢腹板箱梁的畸变控制微分方程.采用弹性地基梁法解出波形钢腹板箱梁的畸变角和畸变双力矩,最终得到纵向畸变正应力.通过算例对比分析相同截面的波形钢腹板箱梁和混凝土箱梁的畸变翘曲正应力,计算结果表明,波形钢腹板箱梁相对普通混凝土箱梁的横向框架刚度较小,因此由畸变产生的翘曲正应力大于混凝土箱梁的畸变翘曲正应力.

According to mechanical characteristics of box girders with corrugated steel webs and theory of box girders,the warping normal stress of box girders with corrugated steel webs caused by distortion is studied.Considering that corrugated webs have fold effects,the corrugated webs are regarded as an orthotropic plate.Distortion governing differential equations of box girders with corrugated steel webs are derived under the equilibrium relation of plane force system within them.Their distortion angle and distortion bimoment are obtained using the beam elastic foundation（BEF） method,and then the longitudinal distortion stress is obtained.An analytical example is given to compare two types of box girders,concrete box girders and box girders with corrugated steel webs.The results of the example demonstrate that the box girders with corrugated steel webs have less lateral frame stiffness than concrete ones;thus,the distortional warping normal stress of box girders with corrugated steel webs is larger than that of concrete box girders.