Seismic performance of concrete joints strengthened with hybrid-fibre-reinforced polymers

This paper presents the results of experimental and numerical investigations performed on nine one-third scaled exterior beam–column joints. They were first damaged in a displacement-controlled manner with constant column axial load and reverse cyclic load at the tip of the beams. The damaged joints were then repaired with new concrete and strengthened with hybrid-fibre-reinforced polymer laminates. These had combinations of natural and glass fibre mat and chopped laminations together with eight layers of glass-fibre-reinforced polymer wrapping. The aim was to restore and enhance seismic capacity parameters such as strength, stiffness, ductility and energy dissipation. It was observed that specimens with hybrid fibre mat laminations and glass-fibre wrapping exhibited a better performance in terms of ductility, with up to 81% increase. Numerical investigations were carried out using finite-element software to validate the experimental results. It was observed that the numerical results were in good agreement.