Zhu Wanxu, Chen Hongbin, Wei Wei, Chen Boxuan, Chen Xuejun
College of Civil and Architecture Engineering, Guilin University of Technology, Guilin 541004, China.
Collaborative Innovation Center for Exploration of Hidden Nonferrous Metal Deposits and Development of New Materials in Guangxi, Guilin 541004, China.
Materials (Basel). 2022 Apr 15;15(8):2895. doi: 10.3390/ma15082895.
Carbon fiber-reinforced polymer (CFRP) cables are anticipated to be employed in larger, longer, and more durable structures in the engineering field. However, its anchorage devices and mechanism should be appropriately developed and improved. At present, mainly relying on the adhesive force, most anchorage devices may lose their efficiency because of adhesive aging and failure or the slip of an individual tendon. A friction-based composite anchorage device with an integrated bearing of inner cone filler (i.e., load transfer media (LTM)) bonding and a single extruding anchor is proposed, and the anchorage mechanism is examined for Φ7 CFRP cables of strength 2400 MPa. Firstly, sufficient conditions for anti-slip failure of CFRP tendons in the anchorage zone are derived by assuming uniform LTM bonding. The obtained results reveal that the smaller inner pore size of the barrel leads to higher efficiency. Additionally, the maximum efficiency depends on the friction coefficient of the contact surface, the inner cone angle of the barrel, and the diameter and quantity of the CFRP tendons. The necessary conditions for the safety of the CFRP tendon anchorage zone are carefully obtained based on the Tsai-Wu failure criterion. It is concluded that the compressive stress of CFRP tendons in the anchorage zone should gradually increase from the load-bearing end to the no-loading end. Additionally, the relations among the anchorage efficiency coefficient and the CFRP tendon diameter , the anchorage length , the dip angle of LTM external conical surface , and the friction angle are derived based on the equivalent failure principle. The CFRP cables of four specifications (i.e., with Φ12, Φ19, Φ37, and Φ121 tendons) are designed under theoretical guidance, and eight static tests are carried out for more verification studies. The test results indicate that the anchorage efficiency coefficient of designed anchorage devices can be over 90%, and even up to 96.8%. Further, the failure modes are divergent destruction, which verifies the reliability of friction-based anchorage devices and provides a solid theoretical foundation for the design and engineering applications of CFRP cables.
碳纤维增强聚合物（CFRP）缆索有望应用于工程领域中更大、更长且更耐用的结构。然而，其锚固装置及机理需要进行适当的开发和改进。目前，大多数锚固装置主要依靠粘合力，由于粘合剂老化、失效或单根钢绞线的滑移，这些锚固装置可能会失去其有效性。本文提出了一种基于摩擦的复合锚固装置，该装置集成了内锥填料（即荷载传递介质（LTM））粘结的承压和单根挤压锚，并针对强度为2400MPa的Φ7 CFRP缆索研究了其锚固机理。首先，通过假设LTM粘结均匀，推导了CFRP钢绞线在锚固区抗滑失效的充分条件。所得结果表明，锚具较小的内孔径可提高效率。此外，最大效率取决于接触面的摩擦系数、锚具的内锥角以及CFRP钢绞线的直径和数量。基于蔡 - 吴失效准则，仔细得出了CFRP钢绞线锚固区安全的必要条件。得出结论，锚固区内CFRP钢绞线的压应力应从承载端到空载端逐渐增加。此外，基于等效失效原理，推导了锚固效率系数与CFRP钢绞线直径、锚固长度、LTM外锥面倾角以及摩擦角之间的关系。在理论指导下设计了四种规格（即分别带有Φ12、Φ19、Φ37和Φ121钢绞线）的CFRP缆索，并进行了八次静载试验以进行更多的验证研究。试验结果表明，所设计锚固装置的锚固效率系数可达90%以上，甚至高达96.8%。此外，破坏模式为分散破坏，验证了基于摩擦的锚固装置的可靠性，为CFRP缆索的设计和工程应用提供了坚实的理论基础。
