Analytical Model for Concrete Cover Separation in Prestressed Near-Surface-Mounted Carbon Fiber-Reinforced Polymer-Strengthened Reinforced Concrete Beams

This study presents a novel method for calculating the stress and bending moment in reinforced concrete (RC) beams strengthened with prestressed near-surface-mounted (NSM) carbon fiber-reinforced polymer (CFRP), focusing specifically on separation failure at the end concrete cover. By characterizing the geometry of the failure body and integrating it with the concrete tooth model, a comprehensive theoretical framework has been developed. This framework utilizes sectional strain distribution characteristics to establish the bending moment–curvature relationship and the load–deflection curve during loading. Comparisons with experimental data confirm the accuracy and applicability of this analytical model. The results demonstrate that the model is capable of accurately predicting the load–deflection behavior of the strengthened beam. Additionally, this study underscores the substantial impact of the CFRP prestress level on the concrete cover separation failure, showing that optimizing prestress settings can effectively enhance the ductility and bearing capacity of the strengthened beam.

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