大直径喷砂FRP筋应力松弛试件锚固方法研究

纤维增强合聚物（FRP）筋具有设计性好，比强度高，不导电、磁和耐腐蚀性强的优点。FRP筋为非均质复合材料，强度高、弹性模量小，有尺寸效应，用于预应力结构是一种趋势，其应力松弛特性指标是一必要的设计参数。通过不同锚固方式的FRP筋应力松弛试验，研究测试大直径喷砂FRP筋应力松弛特性的试件锚固方法和量测方法。研究表明，改进的钢套筒灌胶锚固方法，可有效减少加载过后FRP筋杆体的滑移量，能满足杆体应力松弛实验要求；预置加载设施的混凝土构件模拟锚固法，可用于测试FRP筋锚杆结构的应力松弛综合性状；光纤光栅变形监测方法能用于应力松弛试验，所测应变数据可靠性高。

Anchoring method for stress relaxation specimens with large-diameter sand-surface FRP bars

Recently, due to their high specific strength, non-electric conductivity, non-magnetic nature and corrosion resistance, fiber reinforced polymer (FRP) bars are being used in engineering structures built in corrosive environments to enhance the durability of reinforced concrete (RC). Moreover, because of their high strength, small elastic modulus and remarkable size effect, the FRP bars are applied to pre-stressed structures, and their stress-relaxation feature is an important design parameter. The anchoring and measuring method for stress relaxation specimens with larger-diameter sand-surface FRP bars is studied. The results show that the modified steel sleeve-type anchoring method can reduce the slippage of the specimens, which meets the requirements of specification. The counterpart experimental method of anchoring concrete component with pre-buried loading devices can be used to test the relaxation behavior of anchoring structures. Furthermore, the fiber optic grating technology is employed to monitor the continuous long-term strain process of rod body. The measured strain data are accurate and stable.