[This article belongs to Volume - 53, Issue - 05]
Gongcheng Kexue Yu Jishu/Advanced Engineering Science
Journal ID : AES-14-11-2021-88
Total View : 0

Title : Seismic Fragility Comparative Research of Sea-crossing Bridges with Scour Conditions Under Onshore and Offshore Ground Motions
WANG Debin, XIA Qing, SUN Zhiguo, WANG Dongsheng, LIU Duo,

Abstract :

Onshore ground motions were widely used for seismic analysis of sea-crossing bridges, and the difference between the onshore and offshore ground motions were ignored. Due to soil loss around piles scoured by water for a long time, the stability of substructure of bridge in marine environment was reduced. Taking an approach part of a sea-crossing bridge as an example, a finite element model for this approach part was built by using the ABAQUS software. The pile-soil effect and hydro dynamic force were considered in the model. The probabilistic seismic demand analysis method was used with the fragility analysis of bridge piers under onshore and offshore ground motions with different scour conditions. By drawing the transcendence probability vulnerability curves and the transcendence probability increase diagrams of piers and bearings, the damage regularities of bridges under the onshore and offshore ground motions and different scour depths of bridges key components were studied. The results showed that the bridge piers were more vulnerable under offshore motions than that under onshore motions. With the increase of the local soil scour depth, the failure probability of the bridge piers and bearings increased. The effect of scour depth had a more obvious effect on the failure exceeding probability of the piers. The failure exceeding probability of the piers in bridge longitudinal direction was higher than that in bridge transverse direction under the same intensity of ground motion. The bearings were more vulnerable than bridge piers under the same working conditions. The increase of failure exceeding probability of the bearings under the offshore motions was also generally higher than that under the onshore. As the scour depth increased, the failure exceeding probability of the bearing gradually increased. Comparing with the onshore motions, the scour depth had a more obvious influence on the failure exceeding probability of bridge piers under the offshore motions with the increase of the ground motion intensity.