基于初等梁理论的人字形桥梁结构空间梁格分析

根据初等梁理论,采用空间梁格分析法对一例典型人字形薄壁箱梁桥进行结构简化及模拟分析。分析结果表明:当受荷载桥跨的两端为扭转约束、并在集中荷载和竖向均布荷载作用下时,空间梁格分析法所得结果与板壳模型的计算结果比较接近;当受荷载桥跨的两端为单向铰支座、并在偏心竖向荷载作用下时,由于约束扭转和畸变效应对主线和匝道的影响十分显著,空间梁格分析法所得结果与板壳模型计算结果相异较大,主要原因是初等梁理论不能反应宽翼缘薄壁箱梁约束扭转、畸变及剪力滞效应等受力特点。指出:对于宽翼缘薄壁箱梁桥结构在采用空间梁格分析法时,应同时考虑宽翼缘薄壁箱梁受力的特点对初等梁理论分析方法进行完善。

Space Grillage Analysis of Inverted-Y Shape Bridge Structure Based on General Beam Theory

Based on general beam theory,space grillage analysis method is adopted to carry through structure simplification and simulation analysis for a typical inverted-Y shape thin-walled box beam bridge.Analysis result indicates that the calculation results of space grillage analysis method are close to shell model under concentrated and uniformly distributed load when both ends of the loaded bridge are set torsion restraint.Owing to the important effect of the constrained torsion and distortion for bridge structure,the results of the space grillage analysis method are different from those of the shell model under vertically eccentric load when both ends of the loaded bridge are set bearing of single direction hinge.The main reasons are that general beam theory can not reflect exactly the mechanical behavior of the constrained torsion,distortion and shear lag of wide slab thin-walled box beam.Research results explain that one should take into account the characteristics of the mechanical behaviors of wide slab thin-walled box beam structure to improve the general beam theory.