公路组合桥面钢桁梁桥整体式节点计算对比

钢桁梁桥在进行全桥有限元计算时,节点的精确模拟与否直接影响计算结果的准确性.传统空间梁单元模型只能反映结构的整体受力,不能反映局部详细应力分布,然而局部应力分布也是桥梁设计的重要依据.为了对比分析空间梁单元模型与精细组合单元模型节点刚性对全桥整体变形和应力分布的影响,以跨径90 m、桥面宽18m公路简支钢桁梁桥为研究背景,分别采用Midas Civil与ABAQUS有限元软件建立三维梁单元模型与精细组合单元模型.采用不同恒载与车辆荷载工况进行加载,对比分析了梁单元模型与组合单元模型相应杆件的应力分布与相对差值;最后通过实桥原位实验证明了精细组合单元模型计算结果的有效性.研究表明,三维梁单元模型简单易行,可以快速给出钢桁梁桥整体计算结果,而精细组合单元模型能够准确考虑节点刚性对于钢桁梁桥整体变形的影响,并给出关注部位详细应力分布.

Comparative Research on Calculation of Integral Joints of Highway Steel Truss Bridge with Composite Deck

Accurate simulation of joints has a direct bearing on the accuracy of computer simulation results when computing the full-bridge finite element model. While the 3D-beam element model can only get the stress state of the whole bridge. Local stress distribution, however, is an important basis for bridge design. In order to compare the joints stiffness influence of the 3D-beam element model and the refined combined-element model on the total deformation and stress distribution, this paper based on a simply-supported steel truss bridge with a 90m span and bridge deck width 18m, 3D-beam element model and refined combined-element model were established with Midas Civil and ABAQUS finite element software respectively. With different load cases, the detailed stress distribution and relative difference of corresponding members between the 3D-beam element model and fined combine-element model are compared and analyzed. Finally, the in-situ experiment of the steel truss bridge proves the validity of the calculation results of the refined combined-element model. The 3D-beam element model is simple and easy to operate, which can quickly give the overall calculation results of a steel truss bridge, while the refined combined-element model can accurately consider the influence of joint rigidity on the overall deformation of a steel truss bridge, and give the detailed stress distribution of concerning parts for design optimization.