Experimental Research on Seismic Behavior of Seismically Damaged RC Frame Column Strengthened with Sprayed Hybrid Basalt/carbon Fiber Reinforced Polymer
|School||Wuhan University of Technology|
|Keywords||concrete frame column earthquake damaged reinforced seismicperformance injected fiber polymer basalt fiber hybrid fibers|
Reinforced concrete frame is widely used in Chinese urban housing structural form, in varying degrees of earthquake disasters, except for a few buildings were collapsed or severely damaged, however, most of the houses were mild or moderate injury, which belongs to the scope of "can be repaired" and "can be reinforced ", therefore, to reinforce the concrete frame structure damaged in the earthquake by a scientific and rational, fast and efficient way has become an urgent problem.Injection of FRP is a new technology, which can quickly repair and reinforce damaged housing structure. Compared with other strengthening technologies, injection of FRP reinforcement has many advantages, such as, lightweight but high strength, convenient construction, good durability and quick reinforcement, nice repaired effect and so on.At present, the domestic and foreign research on injection of FRP strengthening methods are mostly adopted by fiber glass fiber materials, but considering to the injection of short GFRP materials are brittle broken, aging and have poor durability and other shortcomings, this paper selects the new basalt fiber to prepare for the injection reinforcement material, major in studying the seismic strengthening effect of injection of BFRP reinforcement work to damaged frame columns structure, this paper mainly completed the following studies:1. Through tensile experiment on12groups of sprayed FRP sheet, the effect of such factors as sprayed fiber length, volume fraction, type of fiber, type of resin matrix, fiber hybrid ratio on elasticity modulus, elongation at break, tensile strength of specimens were discussed.The results showed that:The fibers volume rate in the sprayed FRP composite is higher, the tensile elastic modulus is greater and the elongation at break is lower; The tensile modulus and strength of FRP composite injected by901resin increased greatly. 2. Anti-seismic experiments under horizontal low cyclic reciprocate load were conducted on9reinforced concrete frame columns (7of them were pre-damaged,2of them were directly loading to failure) and seismic reinforcement effect of seismically damaged frame columns strengthened by sprayed hyper BF/CF was discussed. By comparing stress deformation characteristics, failure patterns, ultimate bearing capacity, ductility, hysteresis curves, skeleton curves and energy dissipation capacity of columns before and after reinforcement, Contrastive analysis of seismic reinforcement effect was conducted on columns with different axial compression ratio, the degree of pre-damage, hybrid ratio and different sprayed fiber thickness.The experimental results showed that:Axial compression ratio increases, the yield and ultimate loads of specimens increase largely; The effect of injected by FRP to improve the carrying capacity of the specimens is not obvious; The pre-loss can significantly reduce the energy dissipation capacity of the specimens; Injected fiber thickness increases, to improve the ductility of the specimens is not obvious, but it can significantly improve the energy dissipation capacity of the specimens; Injected by BF or CFRP can simultaneously improving energy dissipation capacity and ductility of specimens.3.The analysis on the bearing capacity of damaged RC frame column strengthened with sprayed hybrid basalt/carbon fiber reinforced polymer was carried out. The calculation formula of bending capacity and shear capacity of damaged RC frame column strengthened with sprayed hybrid basalt/carbon fiber reinforced polymer is established.