浸水效應下跨河橋梁耐震易損性分析

Abstract

本篇之研究考量橋梁受到浸水效應，並模擬其在地震威脅下之破壞機率。為模擬橋梁在浸水效應下之反應，將橋梁之材料之質量重新定義，並進行非線性動力分析。而後透過考量之外力計算出橋梁之可靠度，並探討橋梁在特定重現期距之洪水水位、附加質量方法、地動強度下之易損性。為探討地震事件下之破壞機率，分別求取地震強度、事件發生機率與易損性曲線，而在探討地震威脅發生機率，再取保守計算求得。最後便可依此結構易損性與地震威脅之發生機率求得破壞機率。

The purpose of this study is to assess the failure probability for a water-surrounded river bridge under seismic excitations within its design service period. To simulate the water-surrounded effect of a bridge structure, developing the constitutive law of materials behavior of piers is necessary. In addition, the aforementioned data is utilized to construct a bridge model for performing nonlinear time-history analysis. Based on analysis results, the structural demand is acquired. The structural capacity can be determined from design guideline. The fragility of water-surrounded river bridge and seismic intensity can be evaluated with the information of demand and capacity. This study evaluates seismic intensity and fragility to obtain the failure probability. Finally, the failure probability under seismic and water-surrounded effect within its design service period is calculated by combining structural fragility and the occurrence probability of seismic event.