在弯矩、剪力和反复扭矩复合作用下的碳纤维布加固RC箱梁抗扭性能试验研究

为研究碳纤维布加固弯矩、剪力和反复扭矩复合作用下的钢筋混凝土箱梁的抗扭性能,共设计制作了4根钢筋混凝土箱梁试件,其中3根采取碳纤维布加固、1根不加固作为对比试件。试验在自行研制的扭转试验装置上进行,对箱梁试件同步施加弯矩、剪力和反复扭矩作用。以加固方式和加固数量为主要研究参数,分析了箱梁试件的破坏机理、承载能力、变形能力和滞回性能等。通过各箱梁试件的碳纤维布和钢筋的应变变化规律,探讨了碳纤维布加固箱梁的抗扭工作机理;通过测得的各试件的扭矩-扭转角滞回曲线和骨架曲线,提出了碳纤维布加固钢筋混凝土箱梁的抗扭恢复力模型。从而为碳纤维布加固钢筋混凝土箱梁抗扭性能的理论研究和工程应用提供了重要的依据。

Experiments on the torsional behavior of FRP strengthened RC box beams subjected to combined action with cyclic torque

Experiments on the torsional behavior of RC box beams strengthened with fiber-reinforced polymer(FRP) laminates are performed under the combined action of bending moment,shear and cyclic torque.Four RC box beams are designed and fabricated,of which,three are strengthened with FRP laminates and one is kept as original for comparison purpose.The tests were run on a self-manufactured torsion test apparatus,and the box beams are synchronously subjected to bending moment,shear and cyclic torque.Take the strengthening scheme and the number of FRP layers as the main parameters,the failure mode,torsion capacity,deformation capacity and hysteresis behavior of the specimens are investigated.According to the change of strains in FRP and reinforcement,the torsional mechanism of the FRP strengthened box beams is discussed.Based on the hysteresis and the torque vs.twist-angle curves,a model is developed for the torsional recovering force of the FRP strengthened box beams,which provides an important reference for theoretical study and engineering application of the FRP torsional reinforcement to RC box beams.