Retrofitting techniques for non-ductile reinforced concrete exterior beam-to-column joints subjected to cyclic loading using multi-criteria decision-making

Previous seismic events have emphasised the critical role of beam-column joints in the performance of moment-resisting frames. This study investigates retrofitting techniques for non-ductile reinforced concrete beam-column joints under cyclic loading, evaluating structural performance, environmental sustainability, and economic feasibility. Finite element models were developed and validated using ABAQUS simulations. A parametric study targeting a 37 kN load capacity identified three effective methods: CFRP grids with engineered cementitious composites (ECC), CFRP sheets with steel anchor bolts, and steel jacketing. Among these, CFRP grids with ECC provided the highest structural performance by mitigating failure modes such as cracking. CFRP sheets with steel anchor bolts and steel jacketing also improved performance but exhibited limitations like stress concentration and plastic deformation. A life cycle assessment (LCA) conducted with SimaPro® showed that CFRP sheets with steel anchors had the lowest global warming potential and human health impact. Despite its higher environmental footprint, steel jacketing proved most cost-effective in the life cycle cost (LCC) analysis. A multi-criteria decision-making (MCDM) approach integrating LCA and LCC through the weighted sum method (WSM) ultimately recommended steel jacketing as the optimal retrofitting solution due to its balanced performance, durability, and economic advantages.