Shear behaviour of fire-damaged reinforced-concrete beams

Abstract

This paper experimentally evaluates the shear behaviour of seven reinforced-concrete (RC) beams following fire damage. Three sides of each beam were subjected to an ISO 834-1 standard fire for 2 h and then the beams were tested in shear loading after air cooling. The effects of the shear/span ratio and the heated positions on the shear behaviour of RC beams were investigated. The test results showed that after fire damage, the shear-bearing capacities and the shear stiffness of the RC beams decreased, while the ultimate deformations of the beams increased. With respect to RC beams, the reduction in the flexural-bearing capacity was larger than that in its shear-bearing capacity when its compression zone was subjected to fire. The study of the shear-transfer mechanism indicated that arch action is one of the main contributors to the shear capacity of a RC beam after fire damage. Based on the plastic limit theory, a simplified approach for evaluating the residual shear strength is presented in this study.