A Novel Hybrid Self-Centering Piston-Based Bracing Fitted with SMA Bars and Friction Springs: Analytical Study and Seismic Simulation

Abstract

Self-centering piston-based braced frames (SC-PBBFs) are such structural assemblies that can withstand a severe earthquake through passive control. The self-centering motion of the bracing system curtails the seismic permanent damage of a building, thereby considerably mitigating postearthquake repair costs and downtime. This paper proposes a novel hybrid self-centering piston-based bracing (SC-PBB) equipped with friction springs (FS) and superelastic shape-memory alloy (SMA) bars. Analytical formulas are presented for rapid analysis and preliminary seismic design of the SC-PBBFs fitted with SC-PBBs. The general mechanics of the proposed archetypes confirms their symmetric self-centering behavior. To validate the proposed design procedure, a set of SC-PBBFs fitted with tension-only SMA bars and precompressed FS is examined under far-field ground motions. Effects of prestressing of components and earthquake types (crustal, subcrustal, and subduction) are quantified and compared with the responses of buckling-restrained braced frames (BRBFs). The analysis outcomes revealed the effectiveness of the proposed hybrid SC-PBBF subjected to design-level earthquakes.