A Macro-method for Including Bond–Slip Flexibility Within Fibre Element Formulation for Simulating Hysteretic Behaviour of RC Beam–Column Members

Abstract

Fibre beam–column elements are frequently used in the nonlinear analysis of reinforced concrete (RC) frames. The “plane-sections remain plane” assumption in the fibre element formulation results in perfect–bond between rebar and surrounding concrete matrix, which neglects bond–slip added flexibility effects. This drawback affects the lateral stiffness, deformation, energy dissipation, yield displacement, and ductility of an RC member and consequently the RC structure. In this paper, a simple and effective method is presented for incorporating bond–slip flexibility within the plastic hinge of an RC member into fibre elements available in commercially developed computer programs. The developed macro-method modifies rebar elastic modulus using a rebar elastic modulus modification coefficient determined through a simplified and systematic formulation. Furthermore, in this study main design parameters contributing to rebar modulus modifications are determined. Although the developed formulation is simple, it has adequate accuracy and robustness which are verified using a large number of experimental test results.