Dan Danhui, Jia Pengfei, Li Guoqiang, Niu Po
Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education, Tongji University, Shanghai 200092, China.
Department of Bridge Engineering, Tongji University, Shanghai 200092, China.
Materials (Basel). 2018 Oct 25;11(11):2087. doi: 10.3390/ma11112087.
It is typically difficult for engineers to detect the tension force of prestressed tendons in concrete structures. In this study, a smart bar is fabricated by embedding a Fiber Bragg Grating (FBG) in conjunction with its communication fiber into a composite bar surrounded by carbon fibers. Subsequently, a smart composite cable is twisted by using six outer steel wires and the smart bar. Given the embedded FBG, the proposed composite cable simultaneously provides two functions, namely withstanding tension force and self-sensing the stress state. It can be potentially used as an alternative to a prestressing reinforcement tendon for prestressed concrete (PC), and thereby provide a solution to detecting the stress state of the prestressing reinforcement tendons during construction and operation. In the study, both the mechanical properties and sensing performance of the proposed composite cable are investigated by experimental studies under different force standing conditions. These conditions are similar to those of ordinary prestressed tendons of a real PC components in service or in a construction stage. The results indicate that the proposed smart composite cable under the action of ultra-high pretension stress exhibits reliable mechanical performance and sensing performance, and can be used as a prestressed tendon in prestressed concrete structures.
对于工程师来说，检测混凝土结构中预应力筋的拉力通常很困难。在本研究中，通过将光纤布拉格光栅（FBG）及其通信光纤嵌入由碳纤维包围的复合棒中，制造出一种智能棒。随后，使用六根外部钢丝和智能棒绞合出一条智能复合缆索。鉴于内部嵌入了FBG，所提出的复合缆索同时具备两种功能，即承受拉力和自感应应力状态。它有可能用作预应力混凝土（PC）中预应力增强筋的替代品，从而为检测施工和运营期间预应力增强筋的应力状态提供一种解决方案。在该研究中，通过在不同受力条件下的实验研究，对所提出的复合缆索的力学性能和传感性能进行了研究。这些条件与实际PC构件在使用或施工阶段的普通预应力筋的条件相似。结果表明，所提出的智能复合缆索在超高预拉应力作用下表现出可靠的力学性能和传感性能，可作为预应力混凝土结构中的预应力筋使用。
