Investigation on Flexural Performance of RC Beams Flexurally Strengthened by Soffit-Bonding and Side-Bonding CFRP Sheets

Abstract

It is an effective way to increase the flexural performance of reinforced concrete (RC) beam by externally bonding fiber reinforcement polymer (FRP) laminate on the soffit of the beam. However, there is little investigation on flexural behavior of RC beam by side-bonding FRP laminates. To investigate the difference of flexural behavior between soffit-bonding and side-binding FRP laminates RC beams, a total of 9 RC beams were tested, including 8 strengthened beams and 1 control beam. The test results showed that: the first crack load of RC beam strengthened by side-bonding CFRP laminates is much bigger than that of RC beam strengthened by soffit-bonding CFRP laminates.The first crack load of side-bonding CFRP laminates beams improved significantly;side-bonding and soffit-bonding methods have the same effect on the flexural stiffness of RC beams with same quantity of CFRP laminates before tension steel rebar yielding. However, side-bonding can remarkably decrease the crack width and change the crack pattern.Side-bonding of CFRP laminates can extend the pre-crack stage of the strengthened beam;the first yielding load and the ultimate load of beams cannot be improved significantly by side-bonding FRP laminates.