一种索道桥主索架设参数计算方法

摘要

Attempts to improve the calculation precision of erection parameters for main cables of cableway bridges were made in this study.An algorithm for calculation of erection parameters,which was based on the control principle of un-stressed state for bridges constructed in stages, was introduced by the analytical methodologies in mechanics of materials.The deformation compatibility conditions as a result of the mutual transformation effects of cable sections in cableway bridges between the anchor spans and the main span were included.The study showed that un-stressed length of steel cables behave mutual shift between the anchor spans and the main span in the course of constructing cableway bridges.Errors of the geometric parameters were relatively large, while the parameters of internal forces were relatively small by the approximate analytical method.Existing algorithms based on the finite element method have logical deficiency due to the fact that local mechanics behaviors were used to substitute global ones.The erection parameters of unloaded cables were untrue.The algorithm based on the finite element method uses the calculation models which can better conform to the actual mechanics behaviors of cableway bridges, and the un-stressed length results of steel cables were computed by it satisfy the deformable coordination condition of structural elements.The results were reliable, and its computing efficiency was very high.%为了提高索道桥架设参数的计算精度,基于分阶段施工桥梁无应力状态控制法原理,采用统筹考虑锚跨和主跨缆索架设过程中索段相互转换的变形协调条件的材料力学分析法,提出了基于结构有限元分析理论的主索架设参数新算法.分析及算例计算结果表明:索道桥施工过程中钢索无应力索长在主跨和锚跨之间呈现此消彼长的转换现象;近似解析法的计算结果中钢索几何参数的误差较大,而索力参数的误差较小;既有有限元算法存在用局部结构行为代替整体结构行为的逻辑缺陷,由此计算得到的空缆状态架设参数是失真的.提出的算法的计算模型更符合索道桥的实际力学行为,计算得到的钢索无应力索长结果很好地满足了构件变形协调条件的要求,计算结果可靠,算法效率更高.