Refined Peridynamic Modeling of Bond-Slip Behaviors between Ribbed Steel Rebar and Concrete in Pull-Out Tests

Abstract

Peridynamics (PD) has been increasingly used to study the damage behaviors of reinforced concrete (RC) structures due to its strong capacity in analyzing discontinuous problems. In this paper, bond-based peridynamics (BPD) is enhanced for refined analysis of bond-slip behaviors between concrete and ribbed steel rebar in the pullout test. The enhancement of BPD includes the following: (1) an axial-shear interaction (ASI) model for refined simulation of bond-slip behaviors between steel ribbed rebar and concrete; (2) a nonlinear uniaxial concrete model to avoid excessive compression of concrete bonds; (3) a novel gradually weakening fictitious element (GWFE) approach to improve the stability and convergence of the Newton algorithm in solving the PD equations, e.g., in case of negative concrete stiffness; (4) a horizon updating approach for rebuilding bond interactions when large displacements occur in the bond-slip process; and (5) a parallel computing approach to improve the computational efficiency of refined analysis. The enhanced BPD method is implemented in an open-source finite-element software, OpenSees, and verified by a rebar pullout test. The type of steel rebar rib, strength of concrete, cross-area of steel, and cyclic loading condition are investigated in detail regarding their effects on the stress redistribution and mesoscale crack propagation of the RC members. The results demonstrate that the enhanced BPD modeling method presented herein is capable of fine simulation of bond-slip behaviors in the pullout test, e.g., the strength deterioration, stiffness degradation, and cyclic response.