Abstract
Seismic retrofit of damaged steel school gymnasium with angle braces is often carried out by replacing damaged braces by larger section angle braces with ultimate strength designed connections. However, the effects of the replaced braces for the retrofit against expected seismic input are not confirmed yet. In this paper, a gymnasium damaged by Tohoku Earthquake 2011 was analyzed including the fracture conditions derived from cyclic tests of angle braces. Furthermore, retrofit options using angle braces with ultimate strength designed connections, strength based designed braces, and energy dissipating braces are analyzed using the same model, and their performances are compared including effects on the acceleration response along the roof.
