The majority of steel factory buildings constructed in 1960-70’s in Japan do not display satisfactory seismic performance due to the lack of strength in the brace-end joints or the foundations. The retrofit works that simply add lateral bracings would be undesirable because it would prevent ordinary factory operations. Then, another retrofit approach could be alternative by enhancing ductility of each structural member. In this study, the practical applications to the existing steel factory buildings are presented and the efficiency of the seismic retrofit with ductility enhancement is discussed.
