The purpose of earthquake resistant design for typical bridges is the ‘No Collapse Design’ allowing emergency vehicles just after earthquakes. The Roadway Bridge Design Code provides design provisions to carry out such ‘No Collapse Design’ with a ductile mechanism and response modification factors given for connections and substructure play key role in this procedure. In case of response modification factors for substructure, the Roadway Bridge Design Code provides values considering ductility and redundancy. On the other hand, ‘AASHTO LRFD Bridge Design Specifications’ provides values considering additionally an artificial factor according to the bridge importance categories divided into critical, essential and others. In this study, a typical bridge with steel bearing connections and reinforced concrete piers is selected and different response modification factors for substructure are applied with design conditions given in the Roadway Bridge Design Code. Based on the comparison study of the design results, supplementary measures are suggested required by applying different response modification factors for substructure.

• 국승규(부경대학교 토목공학과) | Seung-Kyu Kook (Department of Civil Engineering, Pukyung Univ., Busan, 48513, Korea) Corresponding author