Seismic behavior and numerical simulation of damaged beam-column joints retrofitted with viscoelastic steel-enveloped elements

This study proposes an innovative retrofitting method to enhance the seismic performance of damaged reinforced concrete (RC) beam-column (B-C) joints by applying viscoelastic pads and steel plates. Five T-shaped RC joints were initially subjected to reverse cyclic loading tests to evaluate their seismic performance. Using limited experimental data, numerical simulations were utilized to capture the behavior of the T-shaped RC joints to assess how variations in the parameters of retrofitting devices influence the retrofitting effect. A detailed comparison between experimental tests and analytical examination of the experimental data revealed that the finite element model effectively replicated the seismic performance of the retrofitted damaged joints. Variations in the viscoelastic pad thickness significantly affected the joints' deformation capacity. Increasing the thickness of the steel plate substantially enhanced the initial stiffness, with a 14 mm thick viscoelastic pad and a 6 mm thick steel plate offering a balanced increase in seismic performance while avoiding excessive material usage.