Exterior reinforced concrete beam column joint subjected to monotonic loading

Abstract

The joints between beams and columns are crucial zones in a reinforced concrete moment resisting frame. The behaviour of such joints greatly influences the strength and ductility of the overall frame. In this research, analysis of three-dimensional numerical models of exterior reinforced concrete beam-column joints under monotonic loading was performed using the finite element ABAQUS package. Concrete and reinforcing steel material nonlinearities, as well as bond characteristics between reinforcing bars and surrounding concrete were considered in the analysis. A parametric study involving thirty joint models was conducted to examine the influence of concrete strength, column axial load, joint stirrups and shape of the beam top reinforcement on the beam tip load and displacement capacities. The concrete dimensions and reinforcement of the studied models were chosen to ensure the occurrence of joint failure. The study showed that the beam tip ultimate load significantly increased as the concrete strength, column axial load and joint stirrups were increased. Joints with L-shaped beam top reinforcing bars exhibited similar performance to those with U-shaped bars. The use of straight bars for beam top reinforcement significantly reduced the beam tip ultimate load. Keywords: Reinforced concrete, Beam-column joint, Finite element, Monotonic loading, Numerical analysis, Bond simulation