Experimental and numerical investigation on seismic performance of retrofitted RC columns with web direct/indirect bonding external H-section

Abstract

This paper presents experimental and numerical investigations of existing reinforced concrete (RC) columns enhanced by two seismic retrofit methods, web indirect bonding and web direct bonding combined with a steel endplate. The former retrofit system is an H-shaped steel member connected to an existing RC column with anchor bolts and an infilled-concrete layer. The latter is quite similar to the web indirect bonding method but incorporates a steel endplate and a stud bolt layer additionally. Three RC columns with/without the retrofitted methods, designated BC, SC-T2, and SC-T4, were built and tested under cyclic loading. The experimental findings showed that the retrofitted RC columns were superior to the non-retrofitted specimen in terms of initial stiffness, peak strength, and energy dissipation capacity. Based on the experimental responses, finite element (FE) models were developed and verified with the experimental results. The results obtained from the simulations were consistent with those from the experiments, indicating the finite element (FE) models can reproduce the seismic responses of bare and retrofitted RC columns with slight simulation variation. Finally, a parametric analysis was carried out to investigate the effect of the material strength and length of the added components on the seismic behavior of the SC-T2 specimen.