Effect of Externally Bonded Strips of Polymer Fiber (frp) on the Shear Strength of R.C Beam

Abstract

This research includes the findings of a workable study investigation for topic of externally strengthening by polymer fiber strips (FRP) of shear span and its impact on the behavior of reinforced concrete beams. The study was carried out by casting (18) concrete beams (1000mm) in length, (150mm) in width and (200mm) in height reinforced by longitudinal steel bars to avoid flexure failure. Two of these beams were considered as controlling beams where its shear span was left without external wrapping by fiber strips. The remaining beams were divided into tow groups where its shear span was wrapped from the bottom and the sides by glass fiber (GFRP) or carbon fiber (CFRP) at (90˚) angle for the first group and (45˚) angle for the second. After these beams were tested the result showed that externally strengthening by polymer fiber strips increases shear strength of the wrapped beams compared to the controlling beams (unwrapped) at ratios based on type of fibers strips, strips thickness and declination. The increase has reached (10% - 28%) for wrapped beams at an angle of (90˚) and (20% - 44%) for wrapped beams at an angle of (45˚). Externally strengthening also increases the absorption energy as well as reducing wrapped beams, ductility compared to controlling beams (unwrapped) with (12% - 23%) for the wrapped beams at an angle of (90˚) and (14% - 37%) for the wrapped beams at an angle of (45˚). .

Keywords

• effect
• externally
• bonded
• strips
• polymer fiber
• shear strength of r
• c beam
• frp