关键词：钢箱单肋拱桥；不稳定模式；安全系数；ANSYS；抗弯刚度
摘 要：Steel single rib box section arch bridge is established on the basis of secondary development using parametric language of large-scale finite element software ANSYS.On the premise of same sectional area A of arch rib,height breadth ratio h/b is changed,and both the spatial instability mode under the condition of arch bridge's dead weight and the stability safety coefficient under the condition of the first step instability mode is calculated.With the aim to optimize distribution of stiffness and stability of single rib arch bridge,the target is to find out a height breadth ratio h/b which can make in-plane and out-plane instability mode coupling,that is to say,equivalent stiffness of in-plane and out-plane of the mode.