Shear performance of stirrup corroded RC beams: Effects of strengthening interventions and corrosion rates

This paper investigates the shear performance of corroded reinforced concrete (RC) beams with different stirrup corrosion rates and strengthening interventions. In this work, eight corroded beams strengthened with various interventions, including U-shaped stirrup, bonded steel plate, and anchored steel plate strengthening techniques, were tested under static loading. The experimental shear capacity, load-deflection response, and failure modes of the unstrengthened and strengthened specimens were carefully studied. Three shear capacity models based on GB50010-2010, ACI 318-08, and Eurocode 2 codes were proposed and discussed. The results showed that all specimens have the same failure mode, that is, the shear-compression failure. The shear capacities are improved by 17.36%-23.61% and 23.76%-38.46% by these interventions for the specimens with 10% and 20% stirrup corrosion rates, respectively. The anchored steel plate technique provides the maximum improvement in the shear capacity. Additionally, the increased stiffness of corroded specimens with strengthening interventions is apparent when the corrosion rate is 10% but not obvious when the corrosion rate is 20%. The models based on GB50010-2010 and ACI 318-08 codes were proved to have higher accuracy but may overestimate the shear capacity. In contrast, the Eurocode 2-based model comes with relatively low prediction accuracy but conservative results, and it is recommended for engineering design.