Study On Shear Property Of RC Beams With FRP Mesh Hoops

Fiber Reinforced Polymer(FRP) has been used widely in civil engineering due to its lightweight, high- strength and good erosion-resistance. Usually, FRP sheets are applied to repair structures and FRP bars to replace steel bars embedded in concrete members. Firstly, the applications and researches of FRP are reviewed in this paper, and then aims at the problems existing, and brings up a new application of FRP, that is replacing steel hoops with AFRP mesh hoops to strengthen shear ability of concrete members. These AFRP mesh hoops were woven as a net by AFRP belts. The erosion of steel stirrups could be avoided. The thesis includes the following parts:The experiment about the properties of AFRP mesh hoop are introduced, including its tension strength and the bond behavior with concrete. The experiment results show that the AFRP belt's tension strength is lower than its original silk, and the thicker the belt is, the lower its strength. The bond strength between AFRP belts and concrete was higher than that between steel bars and concrete.Six RC concrete beams with AFRP mesh hoops and one with steel hoops are tested for shear property. Test variables include shear span ratio, AFRP mesh hoops ratio ,the way of hoops and the variety of aramid fiber etc. Compared with the beams, in which the AFRP mesh hoops were laid 90° to the longitudinal axis of beams, The experiment results show that the cracking load and the ultimate load of beams should be increased when AFRP mesh hoops were laid ±45° with the longitudinal axis of beams, at the same time, the stiffness of beams is enhanced and the deflection is decreased.The shear strength of those beams is analyzed by using ANSYS, which a versatile FEM analysis software. The load-deflection curve, the cracking load and the ultimate load of beams and the strain of AFRP mesh hoops which intersect the main shear crack are acquired, and compared with experiment results, the results indicate that they are in a good agreement.According to the code for design of concrete structures (GB 50010-2002), a mechanical model about shear strength of RC beams with AFRP mesh hoops is established. The coefficient of strain distribution and the effective strength of aramid fiber were analyzed at different shear span to effective depth ratios, and then a formula was deduced.At last, this paper made a summary about experiment results, FEM and theory analysis of shear resistance of RC beams, and some suggestions for further study are put forward.