Retrofitting seismically designed exterior beam-column joints under lateral monotonic loading: A numerical analysis based on experimental testing

Abstract This research paper presents an experimental and numerical study on the behavior of reinforced concrete (RC) in exterior beam-column joints designed for seismic conditions. Three laboratory specimens were prepared and tested to evaluate their load-bearing capacity and study the joint behavior under a constant axial load and a gradually increasing peak monotonic load until failure. The experimental results demonstrated convergence among the specimens in terms of the load-displacement curve, displacement ductility, and energy dissipation. This was further confirmed through the use of a Finite Element (FE) analysis model. The numerical analysis exhibited significant convergence between experimental and numerical results. Additionally, the numerical model was retrofitted using Carbon Fiber Reinforced Polymer (CFRP) in two methods: model 1 (CFRP sheets only) and model 2 (CFRP sheets with strips). The retrofitting with CFRP proved suitable for enhancing structure performance, showing an improvement in failure mode and a significant increase in peak monotonic load and energy dissipation by (31 and 26) % for model 1, and by (47 and 36) % for model 2. This provides valuable insights into the behavior of RC exterior beam-column joints, highlighting the importance of retrofitting with CFRP composites.