Study on the seismic performance of reinforced concrete framed exterior joints with slabs

Abstract

Due to the existence of cast-in-place slab, strong column-weak beam failure mechanism of frame structure will be changed into strong beam-weak column failure mechanism, so it is very necessary to study the influence of cast-in-place slab on seismic performance of frame joints. This paper aims to investigate the seismic performance of reinforced concrete (RC) framed exterior joints with slabs experimentally and numerically. A total of two RC exterior joint slabs were constructed and tested to study their seismic performance under quasi-static reversed cyclic load, including failure modes, crack patterns, stiffness degradation, load capacity and ductility, energy dissipation capacity, and the stress distribution of longitudinal bars and distributed reinforcement of cast-in-place slabs, hysteretic property of the plastic hinge region of beam end was also analyzed. It was found that ultimate bearing capacity and ductility of specimen BSCJ2 showed slightly increase compared to specimen BSCJ1, because that the slab width of specimen BSCJ2 reaches 8 times slab height. A numerical study, using ABAQUS, was also used to study the seismic performance of RC exterior joints for further, the result of the proposed numerical model shows a good agreement with test data. Furthermore, parametric and orthogonal experimental design study were completed to investigate the seismic performance of RC exterior joints, including beam height, beam span, beam-to-slab stiffness ratio, and longitudinal reinforcement ratios. The results indicate that beam-to-slab stiffness ratio significantly enhances ultimate load capacity, ductility and energy dissipation capacity, while the slab reinforcement ratio improves slightly the load-bearing capacity and energy dissipation capacity. On the contrary, increasing the beam span reduces ultimate bearing capacity, ductility and energy dissipation capacity. The orthogonal analysis further demonstrated that beam span exerted the most pronounced influence on both ductility and energy dissipation capacity, followed by beam-to-slab stiffness ratio, while slab longitudinal reinforcement ratio showed relatively minimal impact.