Abstract:There are silt-soft soil layers and seawater layers in the seabed site, which lead to a different mode of seismic action on the seabed from that on land. In order to study the seismic performance of sea-crossing concrete cable-stayed bridge under seabed seismic action, taking a typical double-pylon cable-stayed bridge as an example, the nonlinear finite element dynamic analysis model is established. Based on the strong earthquake database of the K-Net network in Japan, seven strong earthquake records on the seabed and on land are selected respectively for nonlinear time-history analysis. Combined with the characteristics of the structure, the seismic response of various components of sea-crossing cable-stayed bridge is studied, and the differences in seismic performance of the bridge under the different earthquake actions are compared and analyzed. The results show that in most cases, the structural response under seabed seismic action is greater than that under land seismic action. The maximum amplification can be close to 50%. There will be the risk of underestimating the seismic response if using the land earthquakes for seismic analysis and calculation of sea-crossing bridges. The lateral seismic response of the girder of a cable-stayed bridge is often greater than the longitudinal response. The seismic response of short cables of cable-stayed bridge is often greater than that of long cables. Therefore, it is necessary to focus on the lateral vibration of the girder and the damage status of the short cables in the seismic design of cable-stayed bridges.
