Abstract:In the western regions of China with high seismic risks, many pre-stressed concrete continuous rigid-frame bridges with high piers and long spans have been constructed. Generally, cantilever construction technology is used, but the construction period is long. The bridge may suffer earthquakes during construction. The possible seismic damage to the main beam and pier of the rigid-frame bridges in the cantilever construction stage was explored under the strong earthquake. Based on the Miaoziping bridge, which had undergone the Wenchuan earthquake, three structural systems, i.e. maximum cantilever T-frame, asymmetric single cantilever T-frame of side-span-closure, and continuous rigid-frame of the completed bridge, were established to simulate the transition process of cantilever construction from statically indeterminate to once statically indeterminate to multiple statically indeterminate. The strong motion records near the bridge site during the Wenchuan earthquake were selected as the inputs for time history analysis. Combined with the actual earthquake damage of Miaoziping bridge in the completion state, the main beam stress, and piers internal force of the three system structures were analyzed under the strong earthquake. Compared with the bridge completion stage, the top plate and web at the consolidation of piers and girder were also prone to cracking in the maximum cantilever stage under strong earthquakes, but it was not easy to crack in most other positions; In the side-closure-stage, the (principal) tension stress and (principal) compressive stress were also relatively larger in the top plates and bottom plates near the closing section of side-span, the web near the 1/5 to 2/5 area of the side span, and the top plates and bottom plates near consolidation pier-beam, which were also prone to cracking, but the mid-span was not easy cracking. In the two construction phases, although the longitudinal bending moment at the middle-high position of piers was more than twice that of the completed bridge stage, it was not easy to crack; the top and bottom of the main pier were easy to crack, which was consistent with the response of the completed bridge. It is recommended that the seismic importance coefficients of class A continuous rigid frame bridges be 0.76 during the construction period. The research results provide a reference for the construction of high pier and long-span rigid frame bridges with cantilever construction technology meeting earthquakes.