A strength–ductility type seismic retrofit technique for soft first-story reinforced concrete (RC) buildings via adding wing-walls to the existing RC columns is called thick hybrid wall (THW) technique. In this technique, the additional wing-wall does not require longitudinal, transverse and anchor reinforcements; therefore, its construction is easy and cost-effective. In this study, THW technique was applied to an existing pilotis RC building in Okinawa. The objectives of this study were (1) to compare the advantages of THW and conventional retrofit techniques applied to this pilotis building, and (2) to assess the future retrofitting activities through this study.
