CFRP筋黏结型锚具承载力评估试验与理论研究

为探究土木工程中碳纤维增强复合材料(CFRP)筋黏结型锚具的内部力学行为,实现黏结型锚具的优化设计,建立了黏结型锚具承载力预测模型,给出了临界锚固长度计算方法,并通过CFRP筋-锚具拔出试验获得了锚固区筋-黏结介质界面残余黏结力与界面径向压应力的关系式。针对CFRP筋直径和锚固界面径向压应力对锚具计算承载力和临界锚固长度的影响进行了评估。研究结果表明:当黏结界面径向压应力在0~160 MPa范围内时,拔出试验最大拔出拉力、界面最大黏结力及界面残余黏结力随着界面径向压应力增加总体呈线性增加,其中,残余黏结力可达20. 5 MPa。锚具计算承载力随CFRP筋直径或径向压应力增加而呈线性增加,而临界锚固长度随径向压应力增加逐渐减小。对于10mm直径微压纹表面形式CFRP筋黏结型锚具,当界面径向压应力为150 MPa,锚固安全系数为1. 5时,其临界锚固长度为427 mm。

Experimental and theoretical study on load-carrying capacity evaluation of CFRP tendon bond-type anchor

In order to explore the internal mechanical behavior of the tendon bond-type anchor made of the carbon fiber reinforced composite (CFRP) reinforcement in civil engineering and optimize the design of anchor, a prediction model of the bearing capacity of the bond-type anchor is established in this paper. From the prediction model, we can obtained the calculation method of the critical anchorage length. The relationship between the residual cohesive force of the interface of the anchorage zone and the interfacial radial stress was obtained by the pull out test of the CFRP bar anchor. The influence of the diameter of CFRP bar and the radial compressive stress at the anchorage interface on the bearing capacity and critical anchorage length of the anchorage is evaluated. The results showed that when the radial compressive stress of the boundary surface is within the range of 0 ~ 160 MP, the maximum pulling force, the maximum interfacial bonding force and the residual adhesion force of the interface increased linearly with the increase of the radial compressive stress of the interface, and the residual bond strength could reach 20.5 MPa. The calculated bearing capacity of the anchorage increased linearly with the increase of CFRP diameter or radial compressive stress, whereas the critical anchorage length decreased with increasing radial compressive stress. The critical anchorage length of the 10 mm diameter micro pressure stripe surface type CFRP tendons was 427 mm when the radial stress of the interface was 150 MPa and the anchorage safety factor is 1.5.