COLLAPSE AND RESIDUAL DRIFT DURING POST-LOCAL-BUCKLING BEHAVIORS UNDER EARTHQUAKE

Abstract

Low-rise steel structures, when hit by a severe earthquake, are forced to drift beyond their elastic limits associated with local buckling of plate elements of the members. Exact formulae ruling the post-local-buckling behaviors have not been established because of non-stationary complexity. In this study, three models for the post-local-buckling hysteresis loops were proposed on the basis of experiment of box-columns with a large width-to-thickness ratio. The models were applied to response analysis of SDOF systems, from which resistances with respect to collapse and residual drift were calculated for each model. It was found that the elastic-perfectly-plastic model tends to overestimate the performance against collapse and residual drift limits, while the post-local-buckling deteriorating model induced only from monotonic load-deformation relationships provides fairly good estimations for the performance in spite of excluding the Bauschinger effect.