Experimental and Numerical Investigations on the Seismic Behavior of Lightly Reinforced Concrete Beam-Column Joints

Abstract

The experimental and analytical investigations carried out on lightly reinforced concrete beam-column joints subjected to seismic loading are presented in this paper. Five 3/4-scale reinforced concrete beam-column joints were tested to investigate the seismic behavior of the joints. The variables in the tested specimens include column orientations and the presence of slabs on the top of beams. The specimens were subjected to quasi-static load reversals to simulate earthquake loadings. Experimental results obtained include joint shear stresses, joint shear strains, observed cracking and initial stiffness. The test results provided some information about the seismic behavior of the specimens. However, due to the unique nature of the specimens, several key parameters could not be varied. Therefore, to elucidate further information, a numerical study consisting of three-dimensional nonlinear finite-element (FE) models was carried out. The FE models were then validated with the experimental results. This was followed by parametric studies, carried out to understand the effects of several critical factors, including column axial load, ratio of column depth to beam reinforcement bar diameter, and effective slab width, on the complex behavior of the joints.