Abstract
Since the Great Hansin Earthquake in 1995, numerous researches on the seismic performance of steel high way bridge piers consisted of rectangular or circular cross section with constant steel plate thickness have been conducted. But effective results improving their seismic performance such as ductility under the repeated horizontal external forces have not been brought. Use of tapered plate at the bottom of the pier is considered to solve this problem. In this study, four main parameters are selected; 1) mold line of the tapered plate, 2) tapering ratio and failure mode, 3) rigidity of stiffeners, and 4) tapered stiffeners. Fundamental seismic behavior of the steel box section piers with tapered plate is disclosed by both experimental and FEM analysis.