三点弯曲加载FRP强化混凝土梁的破坏分析

The failure analysis of FRP reinforced concrete beam by three-point bending loading

制备了10个混凝土梁、包括8个GFRP加固梁和2个CFRP加固梁,其中部分加固梁在静海水中浸泡三个月.对上述试件进行三点弯曲加载试验,测量最大荷载、最大位移并比较加固前后和海水浸泡前后的强度.通过在梁侧面粘贴应变片,电测观察中性层随载荷的变化情况,分析粘贴FRP后对中性层的影响.由粘贴应变片的测试数据和力学模型得出FRP板轴力与混凝土界面的切应力分布,分析了其破坏行为.

In this paper,10 concrete beams were prepared,including 8 GFRP reinforced concrete beams and 2 CFRP reinforced concrete beams,two of which were immersed in seawater for 3 months.The specimens were loaded by three points bending,and the maximum load and the maximum displacement were measured.The strength of reinforced concrete beams with FRP was compared with that of concrete beams.The variation law of neutral layer of FRP concrete beams with loading is analyzed according to the data of strain gages attached to specimens.The strength difference between immersed specimens and non-immersed ones was discussed in this paper.The tensile stress of FRP cross section and interface shear stress were obtained by the mechanics analysis model,and the failure behaviors of FRP concrete beams were analyzed according to the test data.