Study On Seismic Performance Of RC Vertical Components Strengthened With FRP

Since the last two decades,FRP(Fiber Reinforced Plastics) is widely applied to seismic reinforcement of RC structures for its predominance,such as high strength, high effectiveness,great durability,easy to construct,wide applicability and so on. Based on the recent study, experimental and theoretical study on the seismic performance of RC vertical components such as RC columns, shear walls and RC core walls strengthened with FRP were carried out, which include the following:Seven square reinforced concrete columns were tested under low cyclic alternate load to investigate the seismic performances of square columns strengthened with HFRP in this paper.The results show that the seismic performance could be improved effectively for square columns strengthened with HFRP.The effect of axial load ratio is great,HFRP could confine concrete more effectively when the axial load ratio is low.The higher the axial load ratio is,the lower the confinement and the ductility are.The results also indicate that increasing the amount of HFRP could improve the seismic performance effectively when the axial load ratio is low but barely have any effect when the axial load ratio is high.The seismic performance of the square columns could be improved significantly by increasing the stirrup ratio.Four reinforced concrete shear walls were tested under low cyclic alternate load to investigate the seismic performances of shear walls strengthened with HFRP in this paper. The results show that the stiffness would degrade slower if shear walls were strengthened with HFRP, and it's more effective to low-rise shear wall than mid-rise one. Strengthening the shear walls with the new-style HFRP herein would barely have no effect on improving the bearing capacity but have a great effect on improving the ductility, and it's more effective to low-rise shear wall than mid-rise one. The shear walls would have a good ductility and seismic performance, and the hysteresis curves, the pinching behavior and the capacity of energy consumption of which would be improved effectively by strengthening with HFRP.Two badly seismically damaged RC core walls strengthened with FRP were tested under low cyclic alternate load to investigate the restoration degrees of seismic performances in this paper. The results show that by using FRP reinforcement, although the ductility coefficient is only 50%~60% of the one of the initial RC core walls, the overall behavior of the strengthened RC core walls is not brittle failure with no sign for the peak strength is attained and the failure sign is obviously observed before its failure. The ability of energy consumption is well resumed, the stiffness degrade slower and the shear strength is resumed even increased after reasonable strengthened with FRP. The effect of retrofit is even better to the RC core walls under biaxial loading which is more analogical to the actual earthquake reaction.Based on the experimental data, the formulas to decide the characteristic points of the skeleton curves and the unloading stiffness of the hysteresis curves are suggested by regression analysis. The calculate result of the skeleton curves and the hysteresis curves are compared with the experimental one, and it shows that they tally well.The construction process and things need to pay attention to of the reinforcement with FRP are summed up after extensive investigation and study. Drawing on the quality inspection and assessment methods of construction in different fields, the construction of the reinforcement with FRP and the quality inspection and assessment methods of it are discussed based on the control principle and method of the quality of engineering.