Nonlinear analysis of full-range bending process of prefabricated and cast-in-place concrete composite beams considering interface debonding

This paper conducts four-point negative bending tests on three different designed cross-sectional types of Tshaped composite beams using wet connections. The study analyses the mechanism by which interface debonding impacts the overall performance of the composite beams based on failure modes, load, mid-span deflection, and rebar strain. The findings demonstrate that interface debonding reduces the collaborative performance between the different concrete layers, leading to a decrease in the bending performance of the composite beam. A nonlinear calculating model was developed to calculate the load-deflection response, stress and strain distributions, and the debonding crack length. The model employs different analytical methods for the bonding and debonding regions, thus accounting for the redistribution of stress and strain caused by progressive interfacial debonding. Comparisons between simulated and experimental values confirm the reliability of the model calculations.