Elastoplastic Dilatant Interface Model for Cyclic Bond-Slip Behavior of Reinforcing Bars

This paper presents a new interface model to simulate the cyclic bond-slip behavior of steel reinforcing bars embedded inconcrete. A multi-surface plasticity formulation is used to model two major inelastic deformation mechanisms occurring in bond slip.One is the crushing and shearing of the concrete between the bar ribs, and the other is the sliding between the concrete and bar surfaces.These two mechanisms are represented by different yield surfaces and nonassociated flow rules. The flow rules account for the sheardilatation of the interface induced by the wedging action of the bar ribs and crushed concrete particles. The interface model has been implementedin a finite element analysis program and has been validated with experimental data. The model is easy to calibrate and is able toreproduce the bond-slip behavior of bars under a wide range of confinement situations, including bar pullout and concrete splitting failures.