A shear fiber-bundle plastic-chain model of rebar-concrete interface under monotonic and cyclic loading

•A novel fiber-bundle plastic chain model for rebar-concrete interface is proposed.•Both interfacial elastic damage and irreversible sliding damage are considered.•The physical essence of the coupling of the randomness and nonlinearity is revealed. In this work, a fiber-bundle plastic chain model of rebar-concrete interface under monotonic and cyclic loading is proposed. Considering the sophisticated mechanical behaviour of the rebar-concrete interface under loading, the classical interface model is not able to character the major mechanism as a way of effective stress-driven random slip development in a considerable zone rather a perfect mode-II crack/frictional slip in an idealized plane. The model in this work is able to describe the major mechanism by adopting a fiber-bundle model with physical sense, and also to express the main mechanical behaviours of the interface under monotonic and cyclic loading. This model captures the damage accumulation by the shear fiber failures and the irreversible slips by the effective stress-driven slider slips for the rebar-concrete interface zone, and the physical essence of the coupling of the randomness and nonlinear of bond stress-slip constitutive behaviour is revealed. It is verified by both theoretical analysis and experimental results.