大跨度钢桁梁柔性拱桥稳定性能研究

某跨径布置为(130+338+338+130)m的钢桁梁柔性拱双线铁路桥,其跨度和建设规模在同类桥梁中均属于最大,稳定性问题更为突出,设计难度高。研究在恒载和活载作用下的一类稳定性和二类稳定性。研究结论:(1)一类稳定过高地估计本桥的承载能力,不能作为承载能力的设计依据;(2)二类稳定非线性特征主要表现为材料非线性,几何非线性的影响可以忽略;(3)加载方式对稳定性分析有较大影响,隔跨布置活载时是最不利的受力状态,全桥满布活载时是最理想的受力状态;(4)具备足够的安全储备,结构设计合理。

Study on Stability of Large-span Continuous Steel-truss Bridge Stiffened by Flexible Arch

A large-span double-line railway bridge composed of continuous steel-truss bridge and flexible arch is arranged in spans of 130 m+338 m+338 m + 130 m. Both the span and the construction scale are the larges of its kind. The stability of the bridge remains an outstanding problem and makes the design very difficult. This paper studies on the first type and the second type of stability under dead and live loads.The research results show that( 1) the bearing capacity is overestimated in the first type of stability analysis and can't be based to design the bridge;( 2) the material nonlinear influence is dominated in the second type of stability,and the influence of geometric nonlinearity can be ignored;( 3) the way of loading brings significant impact on stability analysis,and it is the worst case when train live load is placed on every other span,while the ideal loading is achieved when live load is distributed fully on the bridge;( 4) this bridge has sufficient safety bearing capacity and the structural design is reasonable.