Nonlinear Finite Element Analysis of Reinforced Concrete Exterior Beam Column Joint Subjected to Monotonic Loading

Abstract

A numerical analysis of exterior beam-column joint subjected to constant axial load on the column top and monotonic load applied at the beam tip is presented in this work. A strain-based nonlinear finite element program is developed in MATLAB R2009a. The nonlinear analysis of reinforced concrete structural member is carried out considering it as a two-phase system. The concrete in nonlinear range is considered as orthotropic material having different stress-strain relationship in tension and compression. The reinforcement is modeled as a linear elastic – perfectly plastic material. An incremental iterative procedure is adopted with secant stiffness approach for the present nonlinear finite element analysis. The present model is capable of retrieving the load at the initiation of the first crack, the load at the failure and type of failure of beam-column sub-assemblage. The numerical model is also able to locate the position and depth of cracks occurred in the joint assembly under the assumed boundary condition and applied loading. The results of numerical analysis are compared with experimental values and they are in good agreements.

Keywords: Exterior beam column joint, reinforced concrete, monotonic load, nonlinear analysis, secant stiffness, plastic hinge, finite element formulation