Numerical study of steel beam‐to‐column connections retrofitted by shape memory alloy bolts

Abstract

Steel beam‐to‐column connections play a critical role in the overall seismic performance of steel structures, as they transfer the forces and show ductile behavior during lateral loading. Enhancing these connections through innovative retrofitting strategies can significantly improve structural resilience and reduce damage under earthquakes. In this research, a steel frame has been used under cyclic loading to determine effects of different regular bolts, and retrofitting them with shape memory alloy (SMA) bolts. The primary aim is to investigate how SMA bolts, with their unique superelastic properties, influence the strength, ductility, and energy dissipation of retrofitted connections. During analysis, load‐displacement responses, connection rotations, and failure modes were recorded, showing that SMA bolts effectively limited residual deformations, enhanced self‐centering capacity, and provided stable hysteretic behavior compared to regular bolted connections. To extend the findings, a detailed finite element (FE) model of the frame and connections was developed in ABAQUS, incorporating material models capable of reproducing the superelastic response of SMA. The numerical analyses confirmed that SMA‐retrofitted connections substantially reduced residual drifts while maintaining load‐carrying capacity, making them highly effective for seismic resilience.