体外CFRP预应力筋混凝土梁的受力性能

Mechanical Behaviors of Concrete Beam of External Prestressed CFRP Tendons

对体外碳纤维增强复合材料(CFRP)预应力筋混凝土梁的抗弯性能进行了试验研究,根据试验结果对其受力过程、承载力、延性性能和破坏模式等进行了描述,同时编制了体外预应力混凝土梁的非线性全过程分析程序,对体外CFRP预应力筋混凝土梁进行了参数分析,进而推导了体外预应力混凝土梁的简化计算公式。结果表明:理论计算值与试验值吻合较好;张拉预应力筋时是否持荷以及持荷大小对梁的抗弯性能影响可以忽略;体外CFRP预应力筋可以大幅度提高钢筋混凝土梁的承载力,减小梁体变形和开裂程度;梁体内非预应力钢筋可以明显改善体外CFRP预应力筋混凝土梁的裂缝分布和延性;体外CFRP预应力筋混凝土梁的延性指标可达到2.5左右。

Tests were carried out on four concrete T-beams of external prestressed CFRP tendons. According to the test result, the beams＇ bearing capacity, deformation, ductility performance, cracking pattern and failure mode were studied. A program and an analytical model were developed for the analysis of those beams strengthened with external prestressed CFRP tendons and the parametric study was conducted using the program. Results show that the predicted results from the program and analytical model are in good agreement with the test values. The initial loading state on the beam before tendon jacking has insignificant influence to the ultimate loading capacity and deflection. The external prestressed CFRP tendons can improve beams＇ bearing capacity and reduce their deformation and crack remarkably. Non-prestressed tendon in the beam can improve the flexural behaviors effectively since it can lead to the more rational crack distribution and the better ductility. The ductility index of those beams of external prestressed CFRP tendons can reach about 2.5.