预应力CFRP筋弯曲极限承载力理论与试验研究

Theoretical and experimental study on bending ultimate bearing capacity of prestressed CFRP bars

为了得到碳纤维复合材料(CarbonFiber-reinforcedPolymer,CFRP)筋弯曲状态下的极限承载力,开展了不同直径的CFRP筋在不同弯曲半径下抗拉极限承载力研究.首先,根据前人的理论公式,分析CFRP筋直径和弯曲半径对弯曲抗拉强度的影响,在此基础上建立CFRP筋在弯曲状态下极限承载力的理论计算模型;其次,利用建立的模型对2种不同直径的CFRP筋在3种不同弯曲半径下的弯曲极限承载力进行测试,并将测试结果与理论模型计算结果进行对比,验证理论模型的正确性;最后,通过CFRP筋弯曲状态下极限承载力理论计算模型,对不同直径和弯曲半径的CFRP筋弯曲极限承载力进行预测.结果表明:在相同弯曲半径下,CFRP筋的弯曲极限强度随其直径的增大而减小;在相同直径下,CFRP筋的弯曲极限强度随其弯曲半径的增大而增大;当弯曲半径大于5 m时,直径为10 mm和12 mm的CFRP筋的张拉效率均超过90%.本文所建立的理论计算模型的计算结果与试验结果吻合较好,可用于预测不同弯曲工况下CFRP筋的极限承载力.

In order to obtain the ultimate bearing capacity of carbon fiber reinforced polymer(CFRP)bars under bending state,the ultimate tensile bearing capacity of CFRP bars with different diameters under different bending radii was studied.Firstly,the influence of the diameter and bending radius of CFRP bars on the bending tensile strength is analyzed based on existing theoretical formulas,and on this basis,the theoretical model of the ultimate bearing capacity of CFRP bars under bending state is established.Secondly,the bending ultimate bearing capacity of two different diameters of CFRP bars under three different bending radii is tested by model test,and the computational results are compared with the experimental results to verify the theoretical model.Finally,the bending ultimate bearing capacity of CFRP bars with different diameters and bending radius is predicted by the theoretical model of the ultimate bearing capacity of CFRP bars under the bending state.The results show that under the same bending radius,the bending ultimate strength of CFRP bars decreases with the increase of its diameter;and under the same diameter of CFRP bars,the bending ultimate strength of CFRP bars increases with the increase of its bending radius;when the bending radius is greater than 5 m,the tensile efficiency of 10 mm and 12 mm CFRP bars can exceed 90%.The computational result is in good agreement with the experimental result.Hence the theoretical model established in this paper can be used to predict the ultimate bearing capacity of CFRP bars under different bending conditions.