六四军用常备式梁钢拱架稳定性分析

姜旭

济南华鲁中交公路设计有限公司，山东 济南  250000

摘要：为提高钢拱架的稳定性，以六四军用常备式梁钢拱架为研究对象，采用MIDAS/Civil软件建立有限元结构模型，分析钢拱架结构单元的连接条件、钢拱架榀数、结构设计强度极限承载力与结构稳定性的关系。计算结果表明：三角形单元构件的连接条件对结构的稳定性影响不大；随榀数的增多，钢拱架的屈曲临界荷载系数增大，但增大幅度逐渐减小，当榀数达到一定数量时，屈曲临界荷载系数基本不再增大；当榀数较少时，结构的破坏形式为稳定极限承载破坏，当榀数增加到一定数量时，结构的破坏形式为结构设计强度极限承载破坏。为准确表述钢拱架榀数对其稳定性的影响，在3种荷载工况下，拟合不同结构榀数对钢拱架屈曲临界荷载系数、设计强度极限承载力和稳定极限承载力之比的函数式。结果表明拟合函数精度较高，可满足施工设计要求。因此，可通过调整钢拱架榀数改善结构的稳定性。

关键词：钢拱架；有限元分析；稳定性；榀数

Stability analysis of the June Fourth military beam steel arch frame

JIANG Xu

Jinan Hualu China Communications Highway Design Co., Ltd., Jinan 250000，China

Abstract：In order to improve the stability of the steel arch, a finite element model is established to analyze the relationship between the connection conditions of structural elements, the number of steel arches, and the structural design strength ultimate bearing capacity with structural stability by taking the June Fourth military beam steel arch frame. The calculation results show that, the connection conditions of the triangular element members have little effect on the stability of the structure. The buckling critical load factor of the steel arch increases with the increase of the number of trusses, but the increase range gradually decreases. When the number of trusses reaches a certain number, the critical load coefficient of buckling does not increase basically. As the number of trusses is small, the failure mode of the structure is the failure of the stable ultimate bearing capacity, and when the number of trusses increases to a certain number, the failure mode of the structure is the ultimate bearing failure of the structural design strength. The function formula of different structural numbers to the buckling critical load coefficient of steel arches, and the ratio of the design strength ultimate bearing capacity and the stable ultimate bearing capacity was fitted under three load conditions to describe precisely the effect of the number of steel arches on stability. The results show that, the fitting function has high accuracy and meets the requirements of construction design. Therefore, the structural stability can be improved via adjusting the number of steel arches.

Keywords：steel arch frame; finite element analysis; stability; the number of steel arches