大跨简支系杆拱桥非线性稳定性

宁杭高速公路南河大桥为主桥130m跨径简支下承式钢管混凝土系杆拱桥。在考虑了拱桥非线性稳定性影响因素基础上，利用有限元ANSYS结构分析程序，建立了拱桥结构稳定性分析空间有限元模型，给出了该桥常见的失稳屈曲模态，研究了大跨简支系杆拱桥的非线性稳定性求解策略，并对南河大桥简支钢管混凝土系杆拱桥进行了非线性稳定性计算。结果表明，钢管混凝土拱脚处的拱肋首先形成塑性铰，破坏时的极限荷载达到正常使用荷载的3．50倍，满足稳定性要求。

Nonlinear stability of simply supported tied-arch bridge with long span

Nanhe bridge locates on Nanjing-Hangzhou highway.It is a simply supported,concrete filled steel tubular,tied-arch bridge with a span of 130 m.The bridge's 3-D finite element model of stability analysis was created by structural analysis program ANSYS based on considering its nonlinear stability influence factors.Its buckling modes were provided,its nonlinear solution method was discussed,the nonlinear stability calculation of the bridge was performed.The result shows that a plastic hinge is firstly developed at the arch springing,its stability collapse load is 3.5 times larger than the design load,which satisfies the requirement of the bridge stability.1 tab,8 figs,8 refs.