Flexural Behaviour and Stiffness of Reinforced Concrete T-Beams with Bond-Slip Effects

Abstract

This study investigates the stiffness and long-term flexural behaviour of reinforced concrete T-beams by incorporating the effects of bond-slip at the reinforcement–concrete interface. Traditional design approaches often assume a perfect bond, which may lead to an overestimation of stiffness and an underestimation of long-term deflection. In this work, an analytical method is developed to quantify the influence of slip on curvature, stiffness reduction, and deflection. The model integrates essential mechanical parameters of concrete, including its modulus of elasticity, time-dependent deformation characteristics, creep, shrinkage, and the nonlinear interaction between concrete and reinforcement. A comprehensive computational framework is established based on regulatory recommendations and long-term deformation models. The results demonstrate that bond-slip significantly increases deflection and reduces effective stiffness compared to conventional bonded assumptions. The analytical expressions derived in this study provide a more realistic prediction of the flexural response of reinforced concrete beams, especially under sustained loading conditions as time approaches infinity. The proposed method can serve as a practical tool for evaluating long-term serviceability performance and can be applied to further experimental and theoretical research in the mechanics of reinforced concrete structures.