Seismic behaviour of seismic-resilient steel moment-resisting frames equipped with damage-free self-centring column bases

Abstract

Recent destructive seismic events have underlined the need for increasing research efforts devoted to the development of innovative seismic-resilient structures able to reduce seismic-induced direct and indirect losses. For steel Moment Resisting Frames (MRFs), the inclusion of Friction Devices (FDs) in Beam-to-column Joints (BCJs) has been widely investigated as a viable solution to provide both high local ductility and energy dissipation capacity. However, it has been demonstrated that, although using FDs efficiently protects the BCJs’ components from local damage, global damage can still be observed in significant post-earthquake residual drifts. This issue has been tackled by several research works, introducing elastic restoring forces able to regulate the structure’s Self-Centring (SC) capability, having the main advantage of ensuring both the energy dissipation capacity and the SC behaviour of the structure. However, although considerable attention has been given to define innovative technologies for BCJs, further research is still needed to define innovative configurations for Column Bases (CBs), which play a fundamental role in the seismic performance of steel MRFs, and their protection is paramount for the achievement of the structural resilience. In this context, an innovative Damage-Free Self-Centring Column Base (SC-CB) has been recently experimentally developed at the University of Salerno. It consists of a rocking column splice joint where a combination of FDs and PT bars with disk springs dissipates the seismic energy and promotes the connection's SC behaviour. Component tests of an isolated SC-CB specimen showed a good and stable flag-shaped hysteretic behaviour, demonstrating the advantages of this technology in terms of improved SC and energy dissipation capabilities. .. [edited by Author]