Abstract: Arch bridge has been used in China for a long time. In recent years, collapse accidents of arch bridges happen frequently which raised the attention of researchers and engineers. In this paper, based on an actual collapse accident of a reinforced concrete rigid-frame arch bridge, a nonlinear finite element model was built. Firstly, to simulate different constraint conditions at the feet of the piers, two rotation stiffness cases were modeled respectively and the overload-induced progressive collapse procedures were simulated. Secondly, the bridge component importance was evaluated by using the method based on the generalized structural stiffness. It can be concluded that the importance factors are large on the brace and the joint between diagonal braces and horizontal components, which agrees well with the observed collapse process.