The objective of this work is to investigate the fatigue behavior of reinforced concrete(RC) beams strengthened with externally bonded carbon fiber reinforced polymer(CFRP) and steel plate. An experimental investigati...The objective of this work is to investigate the fatigue behavior of reinforced concrete(RC) beams strengthened with externally bonded carbon fiber reinforced polymer(CFRP) and steel plate. An experimental investigation and theoretical analysis were made on the law of deflection development and stiffness degradation, as well as the influence of fatigue load ranges. Test results indicate that the law of three-stage change under fatigue loading is followed by both midspan deflection and permanent deflection, which also have positive correlation with fatigue load amplitude. Fatigue stiffness of composite strengthened beams degrades gradually with the increasing of number of cycles. Based on the experimental results, a theoretical model by effective moment of inertia method is developed for calculating the sectional stiffness of such composite strengthened beams under fatigue loading, and the calculated results are in good agreement with the experimental results.展开更多
The tensile properties of five groups of composite specimens, which consist of steel plate bonded by CFRP,were experimentally researched. The failure types, performing characteristics and failure mechanism of the comp...The tensile properties of five groups of composite specimens, which consist of steel plate bonded by CFRP,were experimentally researched. The failure types, performing characteristics and failure mechanism of the composite specimens were investigated in detail. The influence of different ratio of CFRP on bearing capacity, loading-strain curves, compound modulus, rigidity and ductility of the composite specimens was analyzed. The experimental results indicate that the composite specimen can work harmonically and the steel plate does not break in tension. Comparing with steel plate, the bearing capacity and the rigidity of the composite specimens increase and ductility decreases. The bearing capacity increases sharply with the increase in the number of layers of CFRP. With the increase in CFRP, the yield strength increases slightly and ductility decreases. The experimental researches can provide a theoretical basis for engineering application of combination strengthening.展开更多
Corbels support the crossbeams of half-through arch bridges. They are prone to cracking easily due to their characteristics and complicated loading conditions. Based on a practical diagnosis of a bridge crossbeam, we ...Corbels support the crossbeams of half-through arch bridges. They are prone to cracking easily due to their characteristics and complicated loading conditions. Based on a practical diagnosis of a bridge crossbeam, we bonded steel plates onto bridge corbels to strengthen them. We carried out a numerical analysis on the effectiveness of the reinforcement by using the commercial sof^are ANSYS. The numerical analysis shows that the stresses near the section break increased slightly, but the variation amplitude was small and all the stresses were within an allowable range. The loading test indicates that it is feasible to strengthen the corbel with vertical bonded steel plates. Therefore, the reinforcement is effective and economical. This reinforcement method is suitable for this type of corbel and can be applied in similar cases.展开更多
基金Project(51108355)supported by the National Natural Science Foundation of ChinaProject(2011CDB269)supported by the Natural Science Foundation of Hubei Province,China
文摘The objective of this work is to investigate the fatigue behavior of reinforced concrete(RC) beams strengthened with externally bonded carbon fiber reinforced polymer(CFRP) and steel plate. An experimental investigation and theoretical analysis were made on the law of deflection development and stiffness degradation, as well as the influence of fatigue load ranges. Test results indicate that the law of three-stage change under fatigue loading is followed by both midspan deflection and permanent deflection, which also have positive correlation with fatigue load amplitude. Fatigue stiffness of composite strengthened beams degrades gradually with the increasing of number of cycles. Based on the experimental results, a theoretical model by effective moment of inertia method is developed for calculating the sectional stiffness of such composite strengthened beams under fatigue loading, and the calculated results are in good agreement with the experimental results.
基金Hubei Provincial Important Science and Technology De-velopment Planning Sponsor Projects (No. 20001P2104)The Project of National Natural Science Foundation of China ( No. 50678136)
文摘The tensile properties of five groups of composite specimens, which consist of steel plate bonded by CFRP,were experimentally researched. The failure types, performing characteristics and failure mechanism of the composite specimens were investigated in detail. The influence of different ratio of CFRP on bearing capacity, loading-strain curves, compound modulus, rigidity and ductility of the composite specimens was analyzed. The experimental results indicate that the composite specimen can work harmonically and the steel plate does not break in tension. Comparing with steel plate, the bearing capacity and the rigidity of the composite specimens increase and ductility decreases. The bearing capacity increases sharply with the increase in the number of layers of CFRP. With the increase in CFRP, the yield strength increases slightly and ductility decreases. The experimental researches can provide a theoretical basis for engineering application of combination strengthening.
文摘Corbels support the crossbeams of half-through arch bridges. They are prone to cracking easily due to their characteristics and complicated loading conditions. Based on a practical diagnosis of a bridge crossbeam, we bonded steel plates onto bridge corbels to strengthen them. We carried out a numerical analysis on the effectiveness of the reinforcement by using the commercial sof^are ANSYS. The numerical analysis shows that the stresses near the section break increased slightly, but the variation amplitude was small and all the stresses were within an allowable range. The loading test indicates that it is feasible to strengthen the corbel with vertical bonded steel plates. Therefore, the reinforcement is effective and economical. This reinforcement method is suitable for this type of corbel and can be applied in similar cases.
