Impact of design parameters and cycles of damage loads on CFRP repair effectiveness of Shear-Deficient RC structures

Abstract

• The study utilize experimental static load test to assess the effectiveness of CFRP sheets as externally bonded repair system for shear-deficient RC structures. • The study investigates different shear damage locations, different design parameters, and different pre-repair damage levels. • The CFRP sheets were found to be effective as a shear repair system regardless of the pre-repair damage level, shear damage location and existence of shear stirrups. • The results show no contribution from the shear stirrups to the load capacity at the pre-repair stage for shear damage closer to the support. • The failure mode was a combination of flexural cracks and CFRP delamination of a concrete layer for shear damage at quarter-span, and a combination of shear cracks and CFRP debonding for shear damage close to the support. An experimental static load test was used to assess the shear damage and ascertain the effectiveness of an externally bonded carbon-fibre-reinforced polymer (CFRP) repair system. The static test-based evaluation covers load against deflection, load against steel strain, load against CFRP strain and failure mode. The study investigates different shear damage locations, different shear design parameters and different pre-repair damage levels. A total of eight RC beams were prepared and categorised into two groups with different loading conditions. The first group of beams was tested under a concentrated point load at quarter-span to induce shear damage, while the second group was for shear damage with load positions at 1.5 times the beam depth from the support. The CFRP sheets were found to be effective as a shear repair system regardless of the pre-repair damage level, shear damage location and existence of shear stirrups. The failure mode is a combination of flexural cracks and CFRP delamination of a concrete layer for shear damage at quarter-span and a combination of shear cracks and CFRP debonding for shear damage close to the support.