关键词: 桥梁工程, 肋拱桥, 地震响应, 地震输入

Abstract: The seismic responses of two long-span rib arch bridges of different types were calculated by using response spectrum method and time-history method with four different seismic input modes, i.e. inputting the response spectrum along longitudinal, transverse, vertical direction respectively, and the earthquake action in three directions simultaneously. The main internal forces of main arch ribs caused by seismic action in different directions were analyzed. It is found that the lateral seismic action has a great influence on the internal force of the main arch rib of deck ribbed arch bridge. The lateral seismic action not only causes the out-of-plane internal force of the arch rib, but also causes larger in-plane bending moment and shear force in the arch rib, especially the larger axial force. Therefore, in the seismic calculation of rib arch bridges, seismic action should be input along three directions of the bridge simultaneously, such as longitudinal, transverse and vertical direction. Arch foot is the weak part of the rib arch bridge in the aseismic design, and special attention should be paid to.

Key words: bridge engineering, rib arch bridge, seismic response, seismic input