Experimental investigation and numerical analysis for RC beams strengthened with CFRP after fire damage
XU Zhi-sheng,ZHANG Wei-zhen (Disaster Prevention Science and Safety Technology Institute, Central South University,Changsha 410075,China)
Based on the analysis of the structural damage from fire, the relationship between load and displacement and that between load and stress of RC beams strengthened with CFRP(Carbon Fiber Reinforced Plastics) after fire damage are discussed, by means of a finite element method. The results of numerical calculation and the experimental ones coincide well, and which have great value for civil engineering. RC beams strengthened with CFRP still have a lot of capacity of bearing loads and can increase the ultimate strength and the stiffness of the beams after the steel has yielded. The cracks in the course of loading of beams after strengthening are developed comparatively slowly and in large quantity and intensive. The width of crack is obviously smaller than the unstrengthened beams. The reason is that the restraint function of CFRP limits the further development of the bottom and side cracks of beams, which strengthens the rigidity of the beams greatly. It is found that relatively accurate theoretical results of RC beams strengthened with CFRP through finite element method are obtained.