Study on Fatigue Characteristics of FRP Tendons Anchored by HEM and Development of HEM Anchorage Having Large Capacity with FRP Multiple Cables

疲劳拉伸试验结果表明，采用HEM锚固的CFRP钢绞线的性能优于环氧树脂锚固。为阐明上述差异及两种锚固在疲劳荷载作用下的作用机理，进行了试验和分析研究。此外，大型结构如“斜拉桥”已开发出具有大容量的多根碳纤维布筋的HEM腱夹。本文的主要研究结果总结如下：1。澄清了HEM与环氧树脂锚固在锚固机理上的差异。在树脂锚固中，钢套与CFRP钢绞线之间的相对变形幅值随疲劳加载次数的增加而增大。在树脂锚固加载端，由于CFRP钢绞线相对变形的增加，温度上升至80度，将导致CFRP钢绞线基体树脂的薄弱区发生疲劳。在HEM锚固中，CFRP钢绞线在加载端温度的上升幅度远小于树脂锚固，因为相对变形幅值与树脂锚固相比非常小。3 . HEM的荷载幅值小于环氧树脂的荷载幅值，这是由于剪切预应力的引入影响了荷载幅值的减小。研制了12根碳纤维布锚索的大承载力2500kN的HEM锚索。通过拉伸试验、长期加载试验和疲劳试验，证实了所研制的HEM锚固可以在实际中使用。

From fatigue tensile tests, it was found that the characteristics of CFRP strands using HEM anchorage is advantageous than that of epoxy resin anchorage. To clarify the above difference and the mechanism of both anchorages under fatigue loading the experimental and analytical investigations were made. Also, HEM tendon grip having the large capacity with multiple CFRP strands have been developed for large structure such as "Cable Stayed Bridge". Main results obtained in this study are summarized as follows:1. The difference of anchoring mechanism between HEM and epoxy resin anchorage is cleared. In resin anchorage, the relative deformation amplitude between steel sleeve and CFRP strand has increased according to the increment of cycles of fatigue loading. The temperature rise up to 80 degrees due to the increment of relative deformation in CFRP strand at the loaded end of resin anchorage will cause the weak area of matrix resin of CFRP strand for fatigue.2. In HEM anchorage, the rise in temperature of CFRP strand at the loaded end is much smaller than that of resin anchorage, since the relative deformation amplitude is quite small compare to that of resin anchorage.3. The load amplitude for HEM is smaller than that of the one with epoxy resin, because of the reduction of load amplitude affected by the introduction of shear prestress.4. HEM anchorage having large capacity of 2500kN with twelve CFRP strands has been developed. From the tensile tests, long term loading tests and fatigue tests, it was confirmed that developed HEM anchorage can be used in the practice.