Beam-to-column connections of steel pier is tend to have stress concentration and causes fatigue crack in welding connects flange and web steel plate of beam and pier which is difficult to keep good welding quality. In 1982, crack damage on beam-to-column connection of a T-shape steel pier in Hanshin Expressway is detected for the first case. The damage was repaired by attaching ribs by welding. Another crack was detected on the welding of the ribs and repaired in 1995 but it was cracked again in 2002. In this study, finite element method analysis and stress frequency measurement are conducted to evaluate former and newly proposed retrofit method. Finally, retrofit existing stiffening ribs and patching steel plate with bolt was adopted.
