提篮式简支梁拱组合体系桥的稳定性研究

Study on the Stability of Basket Type Beam Arch Composite Bridge

以长沙市圭塘河通道建设工程一座跨度为84 m的大跨提篮式简支梁拱组合体系桥为工程背景,分别采用屈曲分析和非线性仿真分析两种方法对提篮式简支梁拱组合体系桥的稳定性和失稳模态进行计算,结果表明:该类桥失稳主要为拱顶侧向变形,且在计入初始缺陷后结构稳定系数明显下降,非线性因素对于结构稳定性影响显著。随后又进行了倾角、横撑布置与矢跨比等因素对拱桥稳定性影响的探讨,结果表明:非保向力效应、内倾角、矢跨比与拱肋刚度对结构的稳定性有非常显著的影响;其中倾角以10°~20°为宜、矢跨比取1/3~1/4为宜。而关于横撑的分析结果表明取一形撑与米形撑更有利于拱桥的稳定性。

As the construction of Changsha Guitang River channel the project background of a main 84 m spans basket type beam arch composite bridge,buckling analysis and the non-linear simulation analysis are used to analyze the basket type beam arch composite bridge to get the instability of the bridge and instability mode. The results of calculation show that the main cause for instability of arch bridge is arch lateral deformation. Moreover,the structural stability coefficient is decreased obviously after the analysis include in the initial defect,and the nonlinear factors have significant influence on the stability of the structure. Then,the buckling analysis is used to explore the inclination angle,lateral braces,span ratio,arch rib stiffness and other factors on the stability of arch bridge. The results of calculation show that the influence of the non normal force effect,inclination angle and span ratio on the stability is great. The inclination to 10 ~ 20 degrees is appropriate and the span ratio is 1/3 ~ 1/4. The results of the analysis show that the stability of one font cross brace of the arch bridge is more favorable for the X-shape cross brace.