Short-term load–deflection behavior of corroded RC beams with confinement effect based on the partial-interaction segmental approach

Abstract

This paper presents a segmental approach that quantifies the short-term load–deflection behavior of corroded reinforced concrete (RC) beams confined with stirrups. Corrosion of the reinforcement weakens the bond strength between the concrete and reinforcement, while the confinement effect provided by the stirrups strengthens the bond-slip characteristics. The traditional moment–curvature (M/χ) approach depends largely on the flexural rigidity (EI) to derive the load–deflection responses. This approach becomes semi-empirical after the concrete has cracked because it cannot simulate the slip between the concrete and the reinforcement; therefore, it cannot simulate the tension-stiffening mechanism. In this study, the segmental moment-rotation (M/θ) approach was used to determine load–deflection responses by incorporating the bond-slip characteristics between the concrete and tensile reinforcement. The M/θ approach simulates the tension-stiffening mechanism and thus directly demonstrates the effects of the corrosion and confinement on the bond-slip characteristics. Combining the M/θ approach with the material bond-slip models, the load–deflection responses were quantified for the corroded RC beams confined with stirrups. The predicted load–deflection curves agreed well with the test results. The load–deflection curves with and without confinement for corroded and non-corroded RC beams were then compared in a parametric study. The interfacial fracture energy and the debonding resistance are also discussed due to the confinement effect for corroded RC members.