Upgrading of slab–column connections using fiber reinforced polymers

The results of an experimental program on upgrading of reinforced concrete slab–column connections subjected to monotonic shear and unbalanced moment transfer are presented in this study. Externally installed carbon fiber reinforced polymer (CFRP) stirrups acting as shear reinforcement around the slab–column connection area were used with two patterns of CFRP arrangements. It was found that the proposed method resulted in punching shear capacity increases up to 60% relative to the specimen without any strengthening. In some cases punching shear failure was eliminated with the use of CFRPs as shear reinforcement. Capacities of test specimens were evaluated using punching shear strength provisions of ACI 318-02 and yield line analyses for the test specimens. On the basis of the results of this study, use of CFRPs as externally installed stirrups was found to be successful in strengthening slab–column connections.