Development of fragility curves for bridges in Korea

The purpose of this paper is to develop fragility curves for bridges in Korea. Fragility curves are needed for assessing the vulnerability of bridges to unscheduled events and for setting retrofit and/or repair priorities. Research results show that individual bridges suffer different levels of damage, depending not only on the magnitude of earthquake and distance from the epicenter, but also on the structural characteristics of the bridge and the soil type on which it is built. For the construction of bridge fragility curves for Korea, we used data from 1008 expressway bridges and a statistical regression method. The relationships between peak ground accelerations and vulnerabilities were modeled with logistic curve equations using the bridge classification and models by Hwang, Jernigan and Lin. The primary contribution of this research is that this study is the first of its kind that develops fragility curves for bridges in Korea, which can now be used for various applications that analyze the socio-economic impacts of network vulnerability caused by natural and man-made disasters. Finding a logical and rational basis for transforming the structural disruption ratio of a bridge directly to its functional disruption ratio is left for a future study.