Abstract
Many RC viaducts have been used for traffic facilities for example railway and highway bridges. So it is very important to establish the rational design method of such structures against big earthquakes. The purpose of this study is to evaluate analytically the relationship between the damage index of each member of RC 2-story viaduct and several factors by means of dynamic response analysis. In this study, ductility factor and accumulated plastic strain energy are used as measures of damage index.