Experimental Study And Theoretical Analysis On Flexural RC Beams Strengthened With Externally Bonded CFS

Because CFRP has many advantages, CFRP-strengthening technique attracts eyes of researchers and engineers all over the world.In order to study the behaviors of RC beams strengthened with CFRP, experimental study and theoretical analysis were combined in the process of research. This thesis put forward the results of experimental and analytical studies concerning flexural reinforced concrete beams strengthened with externally bonded CFS to the tension face of the beams.Six rectangular beams with the same size and the same steel bar ratio were tested experimentally to evaluate the strength enhancement provided by CFS. At the same time, ultimate capacity, strain, deflection, cracked width, and failure mode were measured and observed.The results of experiment clearly indicated that after being strengthened, the flexural capacity of beams can be significantly raised by bonding CFS to the tension face of beams, and the meanwhile, the cracks appeared a little later and the space and width became larger. The stiffness of the beams increased, especially after the bending of the steel bars, while the ductility of beams decreased to some extent. This indicates that: strengthening RC beams with bonding CFS to the face of the beams is available.Based on the results of experiment, an available analytical procedure derived from plane assumption for evaluating the ultimate flexural capacity of RC beams strengthened by CFS was put forward. Under three failure modes (the CFS rupture mode, the concrete crushing mode, the concrete crushing as well as the concrete crushing mode),this thesis presented the concrete formulas respectively. After comparing the calculation results and experiment, we find that the calculating results agree with the experimental results well. It proved that the method to calculate the ultimate flexural capacity was effective. So it can be applied in project for reference.