Under Low Temperature Conditions Strengthened By Cfrp Reinforced Concrete Beams Pilot Study

According to the forcing characteristic of the RC members strengthened with externally bonded carbon fiber sheets, the ultimate strength, stiffness and deflection of rectangular section RC beams strengthened with CFRP are calculated, the formulas to calculate the stiffness and the deflection of RC beams strengthened with CFRP is provided when the effect of secondary load are being and not being considered.Based on the analysis of ductility for reinforced beams, the coefficient of section ductility curvature for reinforced beams strengthened with CFRP is deduced. Secondly, from the view of the engineering, an experimental study under low temperature is carried out on normal-section flexural performance for reinforced concrete beams bonded with carbon fiber sheets. Eight beams are designed in this experiment, and one of them is control beam without carbon fiber sheets, three of them are under normal temperature bonded with carbon fiber sheets, four of them are under low temperature bonded with carbon fiber sheets. The experiment study is carried out between normal temperature and low temperature on the flexural strengthened effects, the whole load-deformation process, failure modes, crack characteristics, and the effects of the CFRP usage and the temperature on the strengthened performance, the hypothesis of plane-section is verified by the experiment. The results show that the ultimate bearing capacity of the beams strengthened under low temperature is smaller than those strengthened under normal temperature. Compared with the beams strengthened under normal temperature, the beams strengthened under 1 ow t emperature have wider cracks, the varieties of the strain at local area is obvious, and the ultimate bearing capacity increases wife the increasing usage of CFRP. At the same time, FEM program-ANSYS is used to give nonlinear analysis for the reinforced concrete beams bonded with carbom fiber sheets. Calculated results agree well with experimental results. This paper builds the foundation for the deep research of reinforced concrete beams bonded with carbon fiber sheets under low temperature, and it can be provided as the practice basis on strengthened projects of CFRP under low temperature.