Finite Element Analysis of Reinforced Concrete Beam Column Connection Subjected to Lateral loading

Abstract

The beam column connection is the most critical zone in a reinforced concrete frame. The strength of connection affects the overall behavior and performance of RC framed structures subjected to lateral load and axial loads. Beam column connection may be subjected to large seismic lateral loading and severe ground shaking during earth quakes. The study of critical parameters that affects the overall joint performances and response of the structure is important. Recent developments in computer technology have made possible the use of Finite element method for 3D modeling and analysis of reinforced concrete structures. Nonlinear finite element analysis of reinforced concrete beam column connections subjected to lateral loading was performed in order to investigate joint shear failure mode in terms of joint shear capacity, deformations and cracking pattern using ABAQUS software. A 3D solid shape model using 3D stress hexahedral element type (C3D8R) was implemented to simulate concrete behavior. Wire shape model with truss shape elements (T3D2) was used to simulate reinforcement’s behavior. The concrete and reinforcement bars were coupled using the embedded modeling technique. In order to define nonlinear behavior of concrete material, the concrete damage plasticity (CDP) was applied to the numerical model as a distributed plasticity over the whole geometry. The study was to investigate the most influential parameters affecting joint shear failure due to column axial load, beam longitudinal reinforcement ratio, joint panel geometry and concrete compressive strength. The Finite Element Model (FEM) was verified against experimental tests of two non-ductile exterior and interior RC beam column connection subjected to lateral loading. The model showed good comparison with test results in terms of load-displacement relation, cracking pattern and joint shear failure modes. At yielding of reinforcement and initiation of concrete crushing, the increase in concrete compressive strength influences the overall joint shear stress strain behavior. Other parameters such as column axial load, beam longitudinal reinforcement ratio, and joint panel geometry did not show a distinct and significant effect that can predict the failure. The FEA clarified that the main influential parameter for predicting joint shear failure was concrete compressive strength.