预应力CFRP钢筒混凝土管锚具性能试验研究

Experimental Research on Performance of the Anchor for Prestressed CFRP Concrete Cylinder Pipes

摘要: 针对预应力钢筒混凝土管(Prestressed Concrete Cylinder Pipe，简称PCCP)在使用过程中预应力钢丝易氢脆及锈蚀现象，提出使用CFRP布替代预应力钢丝的思路，并设计新型预应力CFRP锚具，解决CFRP布在PCCP上的锚固问题。文章首先设计并制作了固定端及张拉端锚具，固定端锚具采用缠绕式复合锚具，以先固定后张拉的方式应用在PCCP承口位置；张拉端锚具采用加嵌条带齿平板锚具，以先张拉后固定的方式应用在PCCP插口位置。然后针对锚具进行拉拔试验，最后对该锚具系统开展放张后的预应力损失试验。结果表明：固定端和张拉端锚具盖板螺栓扭矩分别为3 N·m和5 N·m时，CFRP布均为拉断破坏，且拉应力分别可以达到其极限拉应力的90.7%和88.3%；在本文试验条件下，较高应力水平下的CFRP布预应力损失仅为5.84%，满足工程要求。

Abstract: In order to avoid wire breakage due to hydrogen embrittlement or corrosion in prestressed concrete cylinder pipes (PCCP), this paper proposes a method of wrapping CFRP sheets instead of prestressed steel wires around the structures. Moreover, innovative anchors that were used for prestressed CFRP sheets were designed to transfer the forces from CFRP sheets to the body of PCCPS. Firstly, the post-tensioning anchor, which had a shaft to wrap CFRP sheets around it through a groove to grip and prestress the CFRP, and the pre-tensioning anchor, which consisted of two steel plates with embedded strip teeth, were proposed and manufactured. The post-tensioning and pre-tensioning anchors were applied at the socket and spigot end of PCCPs, respectively. Secondly, these two anchors were tensioned experimentally to investigate the tensile performance. Finally, the prestress loss of CFRP sheets anchored with the above anchors was tested. The results show that the failure mode was the sudden tensile failure of the CFRP sheets outside of the anchors when a torque of 3 N·m and 5 N·m was applied on each bolt in the post-tensioning and pre-tensioning anchor, respectively. Moreover, the tensile stress of CFRP sheets at failure reached 90.7% and 88.3% of the ultimate stress of CFRP. Under the conditions of this experiment, the prestress loss of CFRP sheets accounted only for 5.84% of the initial loading stress at higher levels, meeting engineering requirements.