Sensitivity Analysis on Seismic Performance of Pile-Group Supported Bridges under Combined Effects of Scour and Liquefaction Hazards

摘要

Characterizing the effect of varying design parameters on the seismic performance of bridges can assist in optimum seismic design, especially for those in complex geotechnical conditions where scour and liquefaction hazards occur. This paper presents results of sensitivity analyses on the seismic performance of pile-group-supported bridges under combined effects of scour and liquefaction hazards. A fragility-based tornado diagram method is proposed for the sensitivity analyses. The studied parameters include the column height, diameter and axial compressive ratio, pile diameter and center-to-center distance, and relative densities of loose and dense sands. Special attentions are paid to the influence of scour depth on the sensitivity-ranking of the parameters. Main findings are that the pile diameter and center-to-center distance show increasing sensitivity with the increase of scour depth. These two parameters should be treated carefully in the seismic design of scoured bridges in liquefaction ground. On the contrary, relative densities of loose and dense sands that show significant influences for the scenario without scour turn to be the least sensitive parameters for scoured scenarios.