EXPERIMENTAL INVESTIGATION OF THE CONTRIBUTION OF BONDED C-FRP JACKETS TO SHEAR CAPACITY OF RC BEAMS

Abstract

This paper addresses the issue of the shear capacity of concrete elements with T cross-section strengthened externally by applied epoxy bonded Carbon Fibre Reinforced Polymer (C-FRP) jackets. The experimental programme includes four beams constructed and tested for this purpose. Two of them were rectangular cross-sections and two were T-beams. One specimen of each pair was strengthened with bonded C-FRP jackets. The rectangular one was totally wrapped around the cross-section and in the case of the T-beam C-FRP jackets wrapped the vertical sides and the width of the web (U-jacket). All beams were tested in monotonic increased loading until total failure. The strengthened beams exhibited an increase of the maximum shear strength equal to 300% for the totally wrapped rectangular concrete member and 39% for the U-wrapped T-beam in respect to the corresponding nonstrengthened beams. The strengthened beam with slab (T-beam) exhibited shear diagonal cracks and quite brittle shear failure. Premature debonding failure at the concrete – C-FRP adhesive was observed. On the contrary the entire shear performance of the strengthened rectangular beam was substantially improved in comparison to the non-strengthened rectangular one and it exhibited flexural and rather ductile response while failure finally appeared at a high level of loading and deformation along with C-FRP jackets rupture. INTRODUCTION RESEARCH SIGNIFICANCE EXPERIMENTAL PROGRAMME TEST RESULTS AND DISCUSSIONS CONTRIBUTION OF C-FRP JACKETS TO THE SHEAR CAPACITY CONCLUDING REMARKS ACKNOWLEDGMENTS REFERENCES