Shear Strength of Low-Strength RC Beams Strengthened with Glass Fiber Sheets

유리섬유쉬트로 전단보강된 저강도 RC보의 전단강도

The effectiveness of shear strengthening with glass fiber sheets on normal or low strength RC beams have been investigated experimentally. A design compressive strength of concrete of 13.5MPa has been planned considering the degradation state of the existing structure to be strengthened in this study. Also, concrete surface reinforcing agent was applied to increase bond capacity between concrete and GFRP sheets in case of low strength RC beams. Comparing the test results of low and normal strength beams strengthened with GFRP sheets indicated that total shear capacity of beams was decreased with concrete strength decreased, but the shear strengthening capacity of GFRP sheets are hardly affected by concrete strength. In addition, shear strengthening effects of RC beams strengthened with GFRP sheets can be estimated by $\rho_w{\cdot}f_w$ based on the maximum effective strain of FRP sheet proposed by ACI 440.2R recommendation.