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

Abstract

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 t -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 t -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. Notation a shear span d effective height of the cross-section f c compressive strength of concrete L length of the beam M cal calculated moment capacities of specimens M exp experimental moment capacities of specimens V exp: experimental shear forces of specimens V cal: calculated shear forces of specimens å CU maximum strain of concrete ö diameter of reinforcement Conversion factors 1 mm ¼ 0 . 039 in 1 mm 2 ¼ 0 . 00152 in 2 1 kN ¼ 0 . 2248 kips 1 MPa ¼ 145 lbf/in 2

Experimental and Computational Investigation of Hybrid FRP Bonded-Reinforced Concrete Beams under Cyclic Loading

“…It was indicated that hybrid sheets allow the transfer of stress in the hybrid composite between carbon fibres and glass fibres, and further improve ductility. Sakar et al [18] reported results of an experimental research on the application of bidirectional CFRP sheets for retrofitting RC beams under cyclic loading. It was concluded that adding a horizontal ply in the 0 o direction has a considerable effect of increasing the shear capacity.…”

Shear Strengthening of RC Beams Subjected to Cyclic Load Using CFRP Strips

“…These studies indicated that using CFRP for shear strengthening is an effective and convenient method for improving member's strength and/or stiffness. In these studies, the behaviour of shear deficient beams strengthened with CFRP was also investigated [8].…”