斜拉桥双箱单室箱形主梁的空间应力分析

利用结构有限元分析程序ANSYS,对两座大跨度斜拉桥不同长度、不同尺寸的箱形主梁建立了6个有限元模型,并对其进行了施工阶段的空间应力分析。考虑到梁段以外附近区域的作用,在梁两端截面上施加了由平面杆系结构分析所得的端面内力;另外,索力和预加力也施加在相应的位置,分析了不同工况下箱形主梁在自重、索力和预应力作用下的空间应力效应。归纳出斜拉桥中此类双箱单室倒梯形截面的应力分布特点及薄弱环节,并提出优化措施。分析表明:加厚底板对斜拉桥双箱单室箱形主梁应力分布的改善效果最佳。

Three Dimensional Stress Analysis of Main Box Girder with Twin-Box Single Cross Section Used in Cable-Stayed Bridge

By using the structural analysis program ANSYS,six different finite element models were established based on two long-span cable-stayed bridges' box girders with different lengths and dimensions.Three dimensional stress distribution characteristics of the models were analyzed.In order to consider the affections of the adjacent zone out of the girder section,the internal-forces of two-end surface that were obtained by the horizontal shaft system analysis were exerted on each model respectively.Moreover,the weight,cable force and prestressed force were considered.Based on the above,the three-dimensional stresses of the box girder with different situations were analyzed.The disadvantages of twin-box single cross hammerhead sections of cable-stayed bridge were also indicated.By the result,the optimum measures were proposed.Analysis shows that it is the best way to improve the stress distribution of the twin-box single cross section of cable-stayed bridge by thickening the bottom flange.