The investigation into the effect of consecutive earthquakes on the strongback bracing system

Abstract

This paper examines a newly developed seismic-force-resisting system technically known as Strongback. To achieve improved seismic performance, this system combines characteristics of a traditional concentric braced frame (CBF) with a mast to form a hybrid system; the strongback system aims to promote uniform story drifts over the height of a structure. In seismically prone areas, structures are not always subjected to a single earthquake and they are likely to experience seismic events sequentially. Accordingly, this paper deals with design method as well as the nonlinear dynamic behavior of structures equipped with strongback system (SBS). In this regard, three buildings with 3, 6 and 12 stories configured in three diverse forms at the intersection of the braces to the beam were studied. For the sake of dynamic analysis, different earthquake records and 18 various consecutive seismic scenarios were accounted for. Finally, it is concluded that SBS can effectively deconcentrate deformations using the proposed design strategy and prevent the occurrence of the soft-story phenomenon.