Optimal Shear Strengthening of Severely Deficient RC Beam Using JFRP Laminate with Anchor

Abstract

High-strength jute fibre-reinforced polymer (JFRP) laminates have recently been introduced to strengthen RC beams against shear. In contrast to synthetic-based composites, JFRP laminates would be more ductile, compatible with steel shear rebar and effective in reducing debonding due to their lower modulus of elasticity. The prime objective of this research was providing an optimal solution to strengthen a severely deficient RC beam against shear using an externally bonded JFRP laminate with anchor. Fabrication of the JFRP laminate was carried out with the maximum fibre content of 37.5% to obtain high tensile strength. Five full-scale RC beam specimens were cast. Shear strengthening was done by an externally bonded JFRP laminate with double connector, multiple connector and embedded-bar anchor systems. The dimensions of JFRP laminate were obtained based on proposed guidelines. Based on the experimental test, the average tensile strength of the fabricated JFRP laminate was found to be 162 MPa. Results also showed that the JFRP laminate with multiconnector anchor increased the maximum shear capacity of deficient RC beams by 89% and the beams had failed by the fracture of laminate. Beams strengthened with embedded-bar anchor had shown flexural ductile failure. Both beams failed after yielding of flexural bar. The proposed guidelines could be used for shear strengthening of severely deficient beams to enhance the maximum shear capacity using full strength of JFRP laminate with anchor. KEYWORDS: RC beam, Shear strengthening, JFRP laminate, Anchor, Optimal design