FRP加固节点的混凝土框架结构抗震性能试验研究

Experimental study on seismic performance of concrete frame structures with joints retrofitted by FRP

设计了3个1/2缩尺两层两跨RC平面框架结构试件,对其进行了拟静力加载试验,其中2个试件完好时加固,1个试件加载受损后再进行加固,框架结构的节点及梁柱端均采用FRP加固。对比分析了FRP加固RC框架的破坏形态、承载能力、承载力退化、刚度退化、延性、耗能能力等。结果表明:试件加载至荷载下降到峰值荷载的85%为止,FRP加固RC框架结构均未产生严重破坏,滞回环较为饱满,有捏拢现象,承载力及刚度退化缓慢;较之普通RC框架,FRP加固节点的框架结构延性和耗能能力明显提高,具有良好的抗震性能;CFRP加固框架的承载能力、承载力退化、刚度、延性、耗能能力均优于CFRP/GFRP层间混杂加固的效果,但前者的变形能力及损伤容限提高程度不及后者;受损后CFRP加固框架的承载能力、刚度、延性、耗能能力均低于完好加固的效果。

The quasi-static loading test was conducted on three 1 /2 scaled two-bay and two-story RC in-plane frames,where the joint zones and the ends of beams and columns were retrofitted by FRP. When retrofitted,two of the three specimens were in good condition and the third one was damaged. The seismic performance of RC frames retrofitted by FRP was contrastively analyzed,including the failure pattern,bearing capacity,strength and stiffness degradation,ductility,and energy dissipation,etc. Test results show that until the load was dropped below 85% of the peak load,each specimen was not severely damaged. The hysteretic loops were relatively full with the pinching phenomenon. The strength and stiffness degradation were slow. Compared with the unretrofitted RC frame,retrofitted RC frames had good seismic performance,whose ductility and energy dissipation capacity were significantly improved. Furthermore,the retrofitting effects by CFRP were better than those by CFRP / GFRP in bearing capacity, strength and stiffness degradation,ductility and energy dissipation capacity. However,the deformation capacity and increasing range of allowed damage tolerance of the former were less than the latter. The bearing capacity,stiffness,ductility and energy dissipation capacity of damaged frame structure retrofitted by CFRP were all inferior to the retrofitted structures without damages.