Probabilistic Assessment of Strengths of Corrosion-Affected RC Beams

Abstract

Corrosion of reinforcement causes premature deterioration in reinforced concrete (RC) structures and reduces their intended residual service life. Damages to RC structures due to reinforcement corrosion generally manifest in the form of expansion, cracking and eventual spalling of the cover concrete, loss of steel cross-sectional area and loss of bond between corroded reinforcement and surrounding cracked concrete. These damages may sometime result in structural failure. This chapter initially presents predictive models for time-dependent damages in corrosion-affected RC beams, recognized as loss of mass and cross-sectional area of reinforcing bar and loss of concrete section owing to the peeling of cover concrete. Then these models have been used to present analytical formulations for evaluating time-dependent flexural and shear strengths for corroded RC beams based on the standard composite mechanics expressions for RC sections. Further, by considering variability in the identified basic variables that could affect the time-dependent strengths of corrosion-affected RC beams, an attempt is made in this chapter to present simple estimations for the time-dependent mean strengths and time-dependent coefficient of variation (c.o.v.) associated with the strengths for a typical simply supported RC beam. Comparison of presented simple estimations of mean strengths and c.o.v. associated with strengths has been made with those obtained using Monte Carlo simulation.