Strengthening of Existing RC Two-Way Slabs using New Combined FRP fabric/rod Technique

This study presents the results of an experimental program to investigate the effectiveness of an innovative combined FRP technique using combination of externally bonded (EB) FRP fabrics and near surface mounted (NSM) FRP rods for flexural strengthening of existing reinforced concrete (RC) two-wayslabs with low clear cover thickness. Three full-scale RC slabs (1500×1500×120 mm) were tested under monotonic four-point bending. One slab was kept un-strengthened as the control specimen, one slab was strengthened using NSM GFRP rods, and the other one slab was strengthened using combination of EB CFRP fabrics and NSM GFRP rods. The load-deflection responses, strain measurements, and failure modes of the tested slabs were studied and discussed. The behavior of the slab strengthened with this technique was compared to the behavior of the slab strengthened with GFRP rods. The test results confirmed the feasibility and efficacy of this technique in improving the flexural behavior of RC two-way slabs. Strengthened slabs showed an increase in flexural capacity between 250 and 394% over the control specimen. The slab strengthened using this technique showed higher ductility compared to the slab strengthened using GFRP rods. A 3D nonlinear numerical model was also developed using the finite element (FE) method to predict the flexural behavior of the tested slabs. A good agreement between experimental and numerical results was observed.