CFRP加固钢筋混凝土梁的抗剪疲劳试验研究

Shear Fatigue Performance of Reinforced Concrete Beams Strengthened with CFRP Sheet

通过对一组粘贴U型碳纤维布加固钢筋混凝土粱的抗剪疲劳试验，研究了完好加固梁与损伤加固梁的箍筋和碳纤维布应变随疲劳次数增加的变化情况，不同碳纤维布用量对抗剪加固效果的影响以及斜裂缝的扩展变化状况等。试验表明，钢筋混凝土梁粘贴U型碳纤维布后箍筋应变减小20％-50％，斜裂缝宽度减小35％-45％，且碳纤维布用量越大效果越明显，完好粱加固效果优于损伤梁。粘贴碳纤维布可以明显提高钢筋混凝土梁的抗剪疲劳性能，延长钢筋混凝土结构的使用寿命。

A group of RC beams strengthened with carbon fiber-reinforced polymer （CFRP） sheets of U-wraps axe tested in shear fatigue. It is experimentally investigated that the change of stresses of stirrup and CFRP corresponding to the fatigue loads, the reinforcement effect for shearing capacity with different amount of CFRP sheets and the diagonal crack propagation etc for the undamaged beams and damaged beams. The experimental results indicate that the stresses of stirrup is decreased by 20% - 50%, the width of diagonal crack is decreased by 35% - 45%, and the effect is more significant with the larger amount of CFRP sheets, the strengthening effect of the undamaged beams is superior to that of the damaged beams. Accordingly, externally bonded CFRP sheets of U-wraps can improve the shear fatigue performance and increase the fatigue life of reinforced concrete beam significantly.