Corbels constitute what are known as “disturbed” regions in concrete structures, where typical shear failure may be anticipated on the grounds of small shear span-to-depth ratios. The concentration of stress induced by the weight of girders on the very small loadbearing areas in corbels often causes cracking in bridges and other structures. Little experimental research can be found in the literature on the shear strengthening of corbels. In the present study, nine such members were tested. Two had no carbon fibre reinforced polymers attached, while CFRP laminates were externally bonded to the other seven, in a number of different spatial arrangements. Ultimate shear strength was found and compared for all specimens. The results showed that CFRP configuration and geometry directly affected corbel shear strength, which was higher in all the CFRPstrengthened corbels than in the controls. The highest strength values were recorded for specimens whose shear-critical area was wrapped in CFRP.

The ordinary beams theory based on Bernoulli's theorem is not applicable to non linear and non prismatic members, in RC structures like deep beams, pile caps, dapped ended beams and corbels etc. Such structures normally fail due to shear failure rather than flexural failure and cannot be analyzed and designed with the flexural analysis or beam theory. Strut and Tie Model (STM) provides an acceptable analysis and design solution for the non linear and disturbed regions in RC structures. In this research four pile caps, six corbels, three deep beams, and three dapped ended beams, designed on the basis of assumed Strut and Tie Model were tested in the laboratory under monotonic loads. The failure loads were compared with the assumed design loads. It has been observed that STM provides reasonable solution for the design of disturbed region in RC structures. In most of the cases the actual failure loads were reasonably closed to the theoretical design loads. However for generalization of the STM as an alternative design solution, more experimental work is required on non linear and disturbed region