Modeling Residual Flexural Strength of Corroded Reinforced Concrete Beams

This paper presents a new analytical method for evaluating concrete crack development, estimating reinforcing bar bond strength degradation and predicting residual flexural strength of concrete beams affected by reinforcement corrosion. First, cracking development in cover concrete due to reinforcement corrosion is investigated by using the reinforcing bar-concrete model where realistic concrete properties such as bilinear tension softening law for the cracked concrete are considered. Then, the bond strength evolution of the corroded reinforcing bar is evaluated by considering the contributions from adhesion, concrete confinement, and corrosion pressure acting at the bond interface. The effects of cover concrete cracking on the corroded reinforcing bar bond strength are analytically investigated. On the basis of the estimated concrete crack width and reinforcing bar bond strength degradation due to corrosion, the residual flexural strength of corroded concrete beams is predicted by assuming new strain compatibility at the reinforcing bar bond interface. Finally, the results obtained from the proposed methods are examined by experimental and field data available from various sources. From the results, the residual flexural strength of corroded reinforced concrete beams can be largely dependent on the residual bond strength of corroded reinforcing bar, and the failure mode of the beams may be changed from reinforcing bar tensile yielding to reinforcing bar anchorage failure due to reinforcing bar bond strength degradation. The results also show that the proposed analytical approach is capable of providing accurate predictions for concrete cracking, bond strength degradation, and residual flexural strength of corrosion-damaged reinforced concrete beams.

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