Structural health monitoring of concrete structures using fibre-optic-based sensors: a review

Structural health monitoring (SHM) of civil engineering structures has been widely developed to increase safety and to provide cost-effective maintenance programmes. Although the current approaches of SHM systems using traditional single-point sensors - such as electric strain sensors, accelerometers and global positioning system-based sensors have appropriate measurement precision for SHM purposes, they present challenges when deployed in real-scale applications, given the limited number of possible points to assess structural behaviour and the harsh environmental conditions during operation. When it comes to reinforced-concrete structures, the development of health monitoring and damage identification presents further challenges, since this type of structure is affected by a variety of chemical, physical and mechanical degradation processes, has a heterogeneous composition and shows non-linear behaviour. On the other hand, fibre optic (FO) technology can provide integrated sensing along with extensive measurement lengths of high sensitivity, durability and stability, which makes it ideal for the SHM of concrete structures. In this paper, FO sensing principles and the different types of FO sensors for civil structure applications are briefly described and a stateof-the-art review of SHM applied to concrete structures using FO sensors in recent decades is presented.