| Beam-column is an important part of frame structure and play the role in transmission and distribution of internal forces, the deformation of the coordination between components in the structure to guarantee the stability of structure.Previous earthquake damage at home and abroad indicate that the joint is the most easily damaged part of frame structure, the node damaged would make the entire structure in an extremely unfavorable stress state, lead to the collapse of the entire structure. Earthquake in China is frequent, so that study on seismic reinforcement of frame joint is of great practical significance and engineering.This design produced a total of seven high-strength steel fiber reinforced concrete frame beam-column edge joints in a simulated earthquake loads to damage. First crack treatment is for the damaged components and then paste fiber-reinforced materials, referred to as FRP) to make then reinforce and restore. The main parameters of this experiment are: the different types of fiber-reinforced materials (CFRP and glass fiber cloth), different amount of carbon fiber cloth (0 layer,1 layer and 2 layers), different ways reinforcement in the core area (0°paste and 45°pasted two-layer CFRP) and the a different coupling conditions in core area (0 and 2 rowsΦ8).Test on the specimen joint which have been strengthened and repaired by FRP under low cycles loading force, mainly observe and record cracks development,initial cracking load,yield load and yield displacement ultimate load and ultimate displacement and so on. Through the hysteresis curve,skeleton curve and the energy dissipation capacity of specimens reinforced and such indicators,study the carrying capacity, ductility and energy-recovery level of ability to compare the effect of different test parameters on the reinforcement. The results showed that:the way of strengthening and repairing is very effective. significantly ultimate bearing capacity, limit displacement of the damaged specimen and is conducive to seismic; reinforcement effect is improved with layers of carbon increasing; effect of pasting a layer of carbon fiber cloth and a layer of glass fiber cloth is poor, the reinforcing effect of two layers of carbon fiber cloth is superior to two layers of glass fiber cloth; 45°pasting layer CFRP reinforcement in the joint core area is better than 0°pasting layer CFRP; reinforcing effect in the joints core area of two rowsΦ8 o is better than no stirrups of the specimen. Based on that ,facus on analyzing the enhancement mechanism of fiber reinforced materials on the shear carrying capacity of joints in the core area of fiber-reinforced materials and shear strength formula of FRP reinforced damaged high-strength steel fiber concrete frame joint was proposed. |
PDF Full Text Request