Pseudo-dynamic testing, repairability, and resilience assessment of a large-scale steel structure equipped with self-centering 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. Regarding steel Moment Resisting Frames (MRFs), the inclusion of Friction Devices (FDs) in Beam-to-Column Joints (BCJs) has emerged as an effective solution to dissipate the seismic input energy while ensuring a damage-free behavior. Additionally, recent studies have demonstrated the benefits of implementing similar damage-free solutions for Column Bases (CBs). In this context, the authors have recently experimentally investigated a Self-Centering CB (SC-CB) aimed at residual drift reduction. Previous experimental tests only focused on the response of isolated SC-CBs under cyclic loads. Conversely, the present paper advances the research through an experimental campaign on a large-scale steel structure equipped with the proposed SC-CBs, providing valuable insights into the global structural response and improved repairability. A set of eight Pseudo-Dynamic (PsD) tests were conducted considering different records and configurations of the structure. The experimental results highlighted the effectiveness of the SC-CBs in minimizing the residual interstory drifts and protecting the first-story columns from damage, thus enhancing the structure's resilience. Moreover, the consecutive PsD tests allowed investigating the effectiveness of the reparation process in restoring the seismic performance of the ‘undamaged’ structure. An advanced numerical model was developed in OpenSees and validated against the global and component-level experimental results. Incremental Dynamic Analyses were finally performed to investigate the influence of the SC-CBs on the structure's seismic response while accounting for the record-to-record variability.