Seismic performance of reinforced concrete shear walls with hybrid shape memory alloy–steel reinforcement

This study investigates the seismic performance of reinforced concrete (RC) shear walls enhanced with hybrid shape memory alloy (SMA)–steel reinforcement, addressing the challenge of residual deformations in conventional systems. A user-defined material subroutine (UMAT) was developed in the Fortran programming language to simulate the superelastic behaviour of nickel titanium SMA in the Abaqus software program. Both single and coupled wall systems were modelled and subjected to non-linear time-history analyses using the El Centro (1940) and Koyna (1967) earthquake records. Results show that SMA reinforcement can reduce residual drift by up to 70–80% depending on reinforcement ratio compared to traditional steel-only walls. Notably, hybrid configurations such as 4% SMA + 2% steel achieved performance comparable to full-SMA systems, offering a more cost-efficient solution. The numerical model was benchmarked against published results, confirming the accuracy of the simulation approach. These findings demonstrate that SMA–steel hybrid reinforcement is a practical, validated and resilient strategy for seismic design, aligning with contemporary performance-based engineering objectives.