Study On Seismic Performance Of Steel Fiber Composite Bar (SFCB) Reinforced Concrete Structure

Steel fiber composite bars (SFCB) is a kind of composite materials which keep a reinforcement bar as the inner core with longitudinal fiber surrounding outside. With high strength and elastic modulus, good ductility and low price, it has been used in the structures. What’s more, it can effectively reduce the corrosion of reinforcement due to the effect of the surrounded fiber. The existed research show that the composite materials could significantly improve the yield components of secondary stiffness, reduce the residual deformation, and show good seismic performance. In this paper, a SFCB reinforced concrete frame was comprehensively studied through theoretical analysis, experimental studies and numerical simulation.(1) A one-single and one-span of SFCB reinforced concrete frame was designed according to the code for seismic design of building. Then the specimen was loaded under reversed cyclic loading to study the seismic performance. The result showed that there were three stages-elastic, plastic and destroy, and the carrying capacity rised after yielding with no increasing on the the residual displacement. Then the specimen failed in flexural failure with fully of the hysteresis curve and good energy dissipation ability and ductility.(2) Based on Perform-3D, the seismic performance of the SFCB reinforced concrete frame was simulated and compared with that of the test result. Then different parameters, including the axial compression ratios, concrete strength and fiber content, were also simulated to study the effect of them on the seismic behavior of SFCB reinforced concrete frame. The results showed that the axial compression ratio had a big effect on the seismic performance of the frame. The more the axial compression ratio, the steeper the skeleton curve, the worse the seismic performance of the frame. What’s more, the SFCB reinforced concrete frame had a more obvious secondary stiffness, smaller residual displacement and better seismic performance than those of common reinforced concrete frame.(3) Based on the formula for calculating the restoring force model of conventional concrete, a calculation methods of the key parameters of SFCB reinforced concrete frame was proposed combining with the result of experiment and numerical simulation. Then the simulation results were regressed to achieve the rules of the artifacts and uninstall the stiffness degradation of the frame.(4) Based on the skeleton curve model and loading stiffness degradation, the rule of the hysteresis loop of the SFCB reinforced concrete frame was proposed. After that a restoring force model was built and validation of it was verified with the experimental results, loading a foundation for further studying.