An experimental study on shear strengthening of RC T-section beams with CFRP plates subjected to cyclic load

The aim of this experimental study was to investigate the behaviour of reinforced concrete (RC) T-section beams that were strengthened by carbon fibre reinforced polymer (CFRP) plates. Six specimens, one of which was the control specimen and five of which were the shear deficient test specimens, were strengthened with side-bonded and ⍽-jacketed CFRP plates. Unidirectional and bidirectional CFRP sheets were used as strengthening material. Distinct CFRP type, CFRP arrangement, number of sheet layers and wrapping schemes were the variables that were investigated during the experimental programme. The main objective of the study was to obtain ductile flexural behaviour from the shear deficient RC T-section beams. Debonding reduces the strengthening potential of the externally bonded CFRP thus obstructs structures to meet the expected requirement from strengthening materials. To block debonding, mechanical anchorages were used at the end regions of CFRP plates. Test results confirmed that all performance CFRP arrangements differ from type and wrapping scheme improved the strength and behaviour of the specimens in different level significantly. Nevertheless, specimens that were strengthened with ⍽-jacketed bidirectional CFRP showed better strength and behaviour than the remaining specimens. To verify the reliability, test results were compared with results of ACI-440 design code and Concrete Society TR55.