CFN加固钢筋混凝土梁抗弯性能试验研究

Experimental study on flexural behavior of reinforced concrete beams strengthened with CFN

为研究碳纤维网格(Carbon Fiber Net,简称CFN)加固梁的力学性能,对4根CFN加固钢筋混凝土梁进行了抗弯试验,以加固层数、加固方式(是否U型箍加固)为试验参量,分析了试验参量对梁破坏形态、裂缝发展与分布、跨中挠度、混凝土应变、钢筋应变等方面的影响。结果表明:CFN加固降低了混凝土应变、钢筋应变的增长速率,且滞后现象在加载后期更加显著;CFN加固材料对梁的承载力提高主要体现在梁的钢筋屈服之后,跨中挠度缓慢增加,混凝土梁刚度退化缓慢;梁底粘贴一层CFN且设置U型箍加固比单纯在梁底增加CFN粘贴层数对提高梁的抗弯承载力效果明显,由此,给出实际工程中选择加固方式的推荐方案。

In order to study the mechanical properties of carbon fiber mesh(CFN)reinforced beams,four CFN reinforced concrete beams are tested for bending resistance,and the number of layers and reinforcement method(U-ring reinforcement)are tested.The influence of CFN reinforcement on beam failure morphology,crack development and distribution,mid-span deflection,concrete strain and steel strain is analyzed.The results show that:CFN reinforcement could reduce the growth rate of concrete strain and steel strain,and the hysteresis is more significant in the later stage of loading.The increase of bearing capacity of CFN reinforcement material is mainly reflected in the yield of the beam after the yield of the beam is increased,the stiffness of the concrete beam is slowly degraded;After bonding a layer of CFN reinforcement material to the bottom of the beam,setting U-shaped hoops on the side of the beam is more effective than simply increasing the number of CFN bonding layers on the bottom of the beam to improve the flexural bearing capacity of the beam.Therefore,the recommended scheme for selecting reinforcement methods in practical projects is given.