空间扭背索组合梁斜塔斜拉桥极限承载力分析

Analysis about Ultimate Bearing Capacity of Space-Twisting Cable Composite Beam Leaning Tower Cable-Stayed Bridge

为进一步研究新兴空间扭背索组合梁斜塔斜拉桥的力学行为,以某主跨220m的空间扭背索组合梁斜塔斜拉桥为研究背景,采用非线性数值分析方法,并通过现场实测值验证数值模型的有效性,讨论了该桥的非线性响应和稳定性,同时用塑性铰法理论对结构极限承载能力进行了计算。研究发现:与常规斜拉桥相比,由于扭背索索长均匀,降低了拉索垂度影响差异;由于扭背索对主塔的水平约束作用较小,主塔较容易出现失稳;由不同工况分析得出,空间扭背索组合梁斜塔斜拉桥的破坏断面位于中塔柱顶部,锚固区下缘。本文研究结论可为类似桥型的进一步研究提供借鉴。

In order to further study the mechanical behavior of emerging bridge type-space-twisting cable composite beam leaning tower cable-stayed bridge, one space-twisting cable composite beam cable-stayed bridge with 220 m main span was taken as example, nonlinear numerical analysis method was adopted, and the effectiveness of numerical model was proved by field measured values. The nonlinear response and stability of the bridge were discussed, and the ulti- mate bearing capacity was calculated by plastic hinge method. Research shows that： compared with conventional cable-stayed bridge, because the length of twisted cable is uniform, the cable sag effect difference is little;because the horizontal restraint of twisted cable to main tower is little, main tower is easy to appear instability ; from the analysis on different working condition,it is concluded that the damaged section of space-twisting cable composite beam inclined tower cable-stayed bridge is located at the top of middle pylon, the bottom edge of anchorage zone.