波形钢腹板梁桥空间网格分析方法

Analysis method for corrugated steel web beam bridges using spatial grid modelling

至今日本在建和已建的波形钢腹板组合梁桥已经达到200多座,中国达到30多座,桥型有简支梁、连续梁、连续刚构及斜拉桥等,截面形式由最初的单箱单室发展到单箱多室。从受力性能和节约成本上看,50~150m跨径范围是最具有竞争力的。目前设计中多采用空间杆系模型、平面梁格模型和实体模型相结合的计算分析方法,但是,空间杆系模型缺乏空间效应精细化分析,如剪力滞效应、有效分布宽度问题、偏载系数问题等;由于平面梁格法在等效原理上的近似性,不能准确反映箱形组合梁的剪应力分布和顶底板局部受力;实体模型很难和总体计算相结合。而空间网格模型可以实现精细化分析,并且具有分析完整性、验算应力全面性,弥补了目前分析方法的不足。通过实体模型与空间网格模型的实例验证,可知两种模型的应力和位移的计算结果几乎一致,说明了网格模型的适用性和精确性。

Up to now,there are more than 200 corrugated steel web composite beam bridges are in service or under construction and have been constructed. In China, about 30 corrugated steel web composite beam bridges are constructed. The bridge types include the simply-supported bridges,continuous beam bridges,continuous rigid frame bridges and cable-stayed bridge,etc. The section form has developed from the original single-box single-chamber section to the single-box multi-chamber section. From the view of stress performance and cost saving,the spans between 50 m and 150 m are most competitive. At present,the computational analytical method mainly adopts the spatial bar system model,plane beam grillage model or solid model. However,the spatial bar system model is lack of refinement analysis on the space effect,such as the shear lag effect,effective distribution width problem and eccentric load factor problem,etc. Due to the similarity of the plane beam grid method in the equivalence principle,i the shearing stress distribution and local stress of the top and bottom plates of the box type composite beam cannot be reflected. The solid model is very difficult to combine with the overall calculation. Moreover,the spatial grid model can achieve the refinement analysis with the advantages of integrity analysis and the comprehensiveness of the stress checking calculation,thus the deficiency of the current analytical method can be overcome. The calculation results of stress and displacements with the solid model and the spatial grid model agree well with each other,which indicates the applicability and precision of the grid model.