大跨度单线铁路连续梁拱空间稳定性分析

Spatial Stability Analysis of Large-span Single-track Railway Continuous Beam-arch Bridge

由于单线铁路大跨度连续梁拱组合结构横向宽度小,因此,需要重点关注结构的横向刚度和整体稳定性。文中以国内最大跨度的单线铁路连续梁拱——乐清湾铁路楠溪江特大桥主桥70 m+136 m+70 m连续梁拱为例,采用midas软件建立全桥空间有限元模型,分析了结构的空间弹性稳定性,并对全桥横向倾覆稳定性进行了分析。结果表明,该单线铁路大跨度连续梁拱的拱肋面外稳定系数为6.396,面内竖向稳定系数为41.316,满足拱结构稳定系数不小于5的要求;拱肋的面外稳定储备远小于面内稳定储备,面外稳定性是单线连续梁拱的设计控制因素之一,应引起足够重视;在最不利荷载组合作用下,全桥横向倾覆稳定系数为3.95,满足横向倾覆稳定系数不小于1.3的要求。

Due to the small lateral width of single-track railway large-span continuous beam-arch composite structures,it is necessary to focus on the lateral stiffness and overall stability of the structure.Taking the largest span continuous beam-arch of single-track railway in China-the main bridge of the Nan-xi-jiang Extra Large Bridge with the span of(70+136+70)m of Yueqing Bay Railway as an example,the space finite element model of the bridge was established using midas software.Spatial elastic stabilityand lateral overturning stability of the full bridge was analyzed.The analysis results show that the single-track railway large-span continuous beam-arch has an out-of-plane stability factor of 6.396 and an in-plane vertical stability factor of 41.316,which meets the requirement of the arch structure stability factor of not less than 5.The out-of-plane stability reserve of the arch rib is far Less than the in-plane stability reserve,the out-of-plane stability is one of the design control factors for single-track continuous beam-arches,and should be paid enough attention to;under the most unfavorable load combination,the bridge'slateral overturning stability factor is 3.95,which meets the requirement of the lateral overturning stability factor of not less than 1.3.