Shear behavior of corroded reinforced concrete beams after high-temperature exposure

Purpose Corroded reinforced concrete (RC) structures are exposed to fire during their service lives. This study aims to examine the effects of stirrup corrosion, fire exposure duration, shear–span ratio and concrete cover thickness on the shear strength and energy dissipation capacity of RC beams. Design/methodology/approach In total, 12 RC beams were fabricated, and accelerated corrosion tests were performed on the stirrups, after which they were subjected to an International Organization for Standardization 834 standard fire. Finally, the residual shear strength was determined using four-point loading tests. Findings The test results indicated an alteration in the failure modes of the concrete beams owing to the combined effects of stirrup corrosion and fire. When exposed to fire for 2 h or with a stirrup corrosion degree exceeding 5%, the load-bearing capacity of the RC beam decreased by more than 30%. Similarly, the energy dissipation capacity was affected by the stirrup corrosion and fire; a stirrup corrosion degree of 12% resulted in a 33% decrease in the energy dissipation capacity after one hour of fire exposure. Finally, an updated approach for determining the shear capacity is proposed. Originality/value These findings provide a valuable empirical foundation for evaluating the remaining shear behavior of in-service corroded RC beams subjected to high temperatures.