The flexural behavior of eight FRP （ fiber reinforced polymer） strengthened RC （reinforced concrete） beams with different steel corrosion rates are numerically studied by Ansys finite element software. The influen...The flexural behavior of eight FRP （ fiber reinforced polymer） strengthened RC （reinforced concrete） beams with different steel corrosion rates are numerically studied by Ansys finite element software. The influences of the corrosion rate on crack pattern, failure mechanism, ultimate strength, ductility and deformation capacity are also analyzed. Modeling results show that the beams with low corrosion rates fail by the crushing of the concrete in the compression zone. For the beams with medium corrosion rates, the bond slip between the concrete and the longitudinal reinforcement occurs after steel yielding, and the beams finally fail by the debonding of the FRP plates. For the beams with high corrosion rates, the bond slip occurs before steel yielding, and the beams finally fail by the crushing of the concrete in the compression zone. The higher the corrosion rates of the longitudinal reinforcement, the more the carrying capacity of FRP strengthened RC beams reduces. The carrying capacity of RCB-1 （the corrosion rate is 0） is 115 kN, and the carrying capacity of RCB-7 （the corrosion rate is 20% ） is 42 kN. The deformation capacity of FRP strengthened corroded RC beams is higher than that of FRP strengthened uucorroded RC beams. The ultimate deflection of RCB-1 and RCB-7 are 20 mm and 35 nun, respectively, and the ultimate deflection of RCB-5 （the corrosion rate is 10% ） reaches 60 ilUn.展开更多
This paper concerns the bond strength of FRP bars in AAC by the concentric pullout test. Specimens were subjected to compare with mild steel bars. The bond performance including the mode of failure and bond strength w...This paper concerns the bond strength of FRP bars in AAC by the concentric pullout test. Specimens were subjected to compare with mild steel bars. The bond performance including the mode of failure and bond strength was investigated with varying embedment length and surface treatment. Regarding the bond performance, embedment depth has influenced on bond strength as well as the sanded surface. Carbon fiber reinforced polymer （CFRP） pronounced the most promising results with the highest bond strength attained.展开更多
Although several experimental and numerical studies have been carried out on the shear capacity of RC beams retrofitted by carbon or glass fibre-reinforced polymers, there has been little work on hybrid FRP sheet appl...Although several experimental and numerical studies have been carried out on the shear capacity of RC beams retrofitted by carbon or glass fibre-reinforced polymers, there has been little work on hybrid FRP sheet applications, particularly under cyclic loading. In the present research, five RC beams were constructed, and four of which were retrofitted using various schemes of FRP sheets. All beams were subjected to quasi-static cyclic loading in an attempt to represent the effect repetitive loading. The ultimate load, and deflection response at mid-span of the beams were measured and compared with predictions of a computational model based on finite element analysis. Experimental results demonstrated that hybrid applications of FRP sheets can improve the shear performance of retrofitted RC beams and increase the ultimate strain of the FRP sheets at failure. The results of the computational model were in reasonable agreement with the corresponding experimental results.展开更多
Strengthening of RC structures with externally bonded FRP （fiber reinforced polymers） has become an important challenge in civil engineering. Epoxy is the main bonding agent used so far, but in the case of a fire, i...Strengthening of RC structures with externally bonded FRP （fiber reinforced polymers） has become an important challenge in civil engineering. Epoxy is the main bonding agent used so far, but in the case of a fire, it is subjected to complete loss of his bonding capabilities. Mineral based composites strengthening systems consist of FRPs and a cementitious bonding agent which form a repair or strengthening system that is more compatible with the concrete substrata, and roved its efficiency. The current research introduces the use of a special cementitious material ＂Grancrete＂ as a bonding agent. Test results of 32 T-section RC beams strengthened with various FRG （fiber reinforced Grancrete） strengthening systems are presented. The results demonstrated that most of the specimens were likely to fail by debonding of the FRP from the concrete either at the ends or at intermediate flexural cracks. This paper presents an in-depth study aimed at the development of a better understanding of debonding failures in RC beams strengthened with externally bonded FRP systems. Different analytical models, published in the literature for plate end debonding, are reviewed and compared to test results. The results also demonstrated that when using U-wraps, the specimens were likely to fail by FRP sheet rupture.展开更多
Fiber reinforced plastics (i. e. FRP) rebars are one kind of high-performance composite materi- als used in concrete structures of civil engineering. Compared with ordinary steel rebars, FRP rebars have the characteri...Fiber reinforced plastics (i. e. FRP) rebars are one kind of high-performance composite materi- als used in concrete structures of civil engineering. Compared with ordinary steel rebars, FRP rebars have the characteristics of high tensile strength, an- tisepsis, light weight, low elastics modulus and low shear strength, et al. At present time, FRP re- bars have been studied and applied in Europe, America and Japan Since 2000, in the Fund of NS- FC, we systematically carried out experimental and theoretical studies on FRP rebars The progress of our research is briefly introduced in this paper.展开更多
基金The National Natural Science Foundation of China(No.51278118)Scientific and Technological Research Project of Ministry of Education(No.113028A)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK2012756)the Program for Special Talents in Six Fields of Jiangsu Province(No.2011-JZ-010)
文摘The flexural behavior of eight FRP （ fiber reinforced polymer） strengthened RC （reinforced concrete） beams with different steel corrosion rates are numerically studied by Ansys finite element software. The influences of the corrosion rate on crack pattern, failure mechanism, ultimate strength, ductility and deformation capacity are also analyzed. Modeling results show that the beams with low corrosion rates fail by the crushing of the concrete in the compression zone. For the beams with medium corrosion rates, the bond slip between the concrete and the longitudinal reinforcement occurs after steel yielding, and the beams finally fail by the debonding of the FRP plates. For the beams with high corrosion rates, the bond slip occurs before steel yielding, and the beams finally fail by the crushing of the concrete in the compression zone. The higher the corrosion rates of the longitudinal reinforcement, the more the carrying capacity of FRP strengthened RC beams reduces. The carrying capacity of RCB-1 （the corrosion rate is 0） is 115 kN, and the carrying capacity of RCB-7 （the corrosion rate is 20% ） is 42 kN. The deformation capacity of FRP strengthened corroded RC beams is higher than that of FRP strengthened uucorroded RC beams. The ultimate deflection of RCB-1 and RCB-7 are 20 mm and 35 nun, respectively, and the ultimate deflection of RCB-5 （the corrosion rate is 10% ） reaches 60 ilUn.
文摘This paper concerns the bond strength of FRP bars in AAC by the concentric pullout test. Specimens were subjected to compare with mild steel bars. The bond performance including the mode of failure and bond strength was investigated with varying embedment length and surface treatment. Regarding the bond performance, embedment depth has influenced on bond strength as well as the sanded surface. Carbon fiber reinforced polymer （CFRP） pronounced the most promising results with the highest bond strength attained.
文摘Although several experimental and numerical studies have been carried out on the shear capacity of RC beams retrofitted by carbon or glass fibre-reinforced polymers, there has been little work on hybrid FRP sheet applications, particularly under cyclic loading. In the present research, five RC beams were constructed, and four of which were retrofitted using various schemes of FRP sheets. All beams were subjected to quasi-static cyclic loading in an attempt to represent the effect repetitive loading. The ultimate load, and deflection response at mid-span of the beams were measured and compared with predictions of a computational model based on finite element analysis. Experimental results demonstrated that hybrid applications of FRP sheets can improve the shear performance of retrofitted RC beams and increase the ultimate strain of the FRP sheets at failure. The results of the computational model were in reasonable agreement with the corresponding experimental results.
文摘Strengthening of RC structures with externally bonded FRP （fiber reinforced polymers） has become an important challenge in civil engineering. Epoxy is the main bonding agent used so far, but in the case of a fire, it is subjected to complete loss of his bonding capabilities. Mineral based composites strengthening systems consist of FRPs and a cementitious bonding agent which form a repair or strengthening system that is more compatible with the concrete substrata, and roved its efficiency. The current research introduces the use of a special cementitious material ＂Grancrete＂ as a bonding agent. Test results of 32 T-section RC beams strengthened with various FRG （fiber reinforced Grancrete） strengthening systems are presented. The results demonstrated that most of the specimens were likely to fail by debonding of the FRP from the concrete either at the ends or at intermediate flexural cracks. This paper presents an in-depth study aimed at the development of a better understanding of debonding failures in RC beams strengthened with externally bonded FRP systems. Different analytical models, published in the literature for plate end debonding, are reviewed and compared to test results. The results also demonstrated that when using U-wraps, the specimens were likely to fail by FRP sheet rupture.
基金Support for this research by the Fund of Rising-Star Plan of Shanghai Scientific and Technical Committee(No.02QF14047)the Fund of National Natural Science Foundation of China(No.50008012)is gratefully acknowledged.
文摘Fiber reinforced plastics (i. e. FRP) rebars are one kind of high-performance composite materi- als used in concrete structures of civil engineering. Compared with ordinary steel rebars, FRP rebars have the characteristics of high tensile strength, an- tisepsis, light weight, low elastics modulus and low shear strength, et al. At present time, FRP re- bars have been studied and applied in Europe, America and Japan Since 2000, in the Fund of NS- FC, we systematically carried out experimental and theoretical studies on FRP rebars The progress of our research is briefly introduced in this paper.
