Seismic performance of hybrid self-centring steel-timber rocking core walls with slip friction connections

Abstract

While structures with conventional lateral force resisting systems are designed to meet the life safety criteria for the residents during and after a seismic event, they are allowed to tolerate the expected structural damage. This damage might be because of the residual displacements after the earthquake or the lack of ductility in the system. Despite the fact that the allowable damages are intended to be repairable, however, in most cases the repairs are highly uneconomical. A self-centring hybrid steel-timber rocking core wall system (SC-RW) is developed to provide sufficient ductility in addition to a significant amount of energy dissipation while it limits the residual drift and the associated damage. This system is comprised of one or more rocking cross laminated timber (CLT) walls with slip friction connections as the main lateral resisting system and steel beams and columns to resist against gravity loads. Horizontally oriented post-tensioned strands through the beams provide additional moment resistance at the beam-column interface to re-centre the structure after the earthquake. The efficiency of the proposed system is investigated under cyclic and seismic loading regimes. Furthermore, a preliminary displacement based design approach for a SC-RW system is introduced. Dynamic time-history simulations confirm an excellent behaviour in terms of drift capacity, residual displacement and peak roof accelerations.