Seismic performance assessment of building retrofitted with superelastic shape memory alloy steel slit damper (SMA-SSD)

Recent seismic vulnerability to high-rise buildings has driven interest in passive dampers to reduce damage and prevent collapse. Among these, yield dampers are commonly used, yet their efficacy in stable energy dissipation and residual deformation remains uncertain, often rendering buildings non-operational after an earthquake. A modification of yield damper i.e. steel slit damper (SSD) supplemented with superelastic shape memory alloys (SMAs) has been proposed with a noble and simple 2D modelling in SAP2000. The SSD's performance was analysed for various fractions of SMA strength based on energy dissipation capacity and residual deformation. Cyclic loading tests revealed that increasing SMA fraction decreased energy dissipation capacity by 20 %–45 % but improved recentring by 55 %–100 %, than SSD. Pushover analysis of 5, 10, and 20-story buildings indicated that SMA-SSD had minimal impact on the structural performance, but improves load-carrying capacity by 5 %–20 % at a 2 % drift ratio and shifted damage state from collapse to immediate occupancy. Also, SMA-SSD enhances interstorey and residual interstorey drift control efficiency without sacrificing the acceleration control efficacy. Incremental dynamic analysis (IDA) under near-fault earthquakes revealed that the SMA-SSD increased spectral acceleration at 50 % failure probability, improving peak floor acceleration (5 %–27 %), interstorey drift (15 %–63 %), residual drift (27 %–95 %), and system-level failure (10 %–85 %), compared to the SSD.