Distributed Optical Fiber Sensors for Monitoring of Civil Engineering Structures

Abstract

Distributed Fiber Optics Sensing (DFOS) is a mature technology, with known, tested, verified, and even certified performance of various interrogators and measurement methods, which include Distributed Temperature Sensing (DTS), Distributed Temperature-Strain Sensing (DTSS), and Distributed Acoustic Sensing (DAS). This paper reviews recent progress in two critical areas of DFOS implementation in large scale civil engineering structures. First is the substantial improvement in sensing accuracy achieved by replacing Brillouin scattering-based measurements with its Rayleigh counterpart. The second is progress in acquisition speed and robustness, as now engineers can observe parameters of interest in real-time, and make informed, operational decisions regarding quality and safety. This received a high valuation from field engineers when used during the construction stage of the project. Furthermore, this change in the use of DFOS in civil engineering greatly increases the practical possibility of installing FO cables permanently. The same FO cables can be later used for long-term monitoring, during maintenance periods throughout the structure’s lifetime. To illustrate these two advances, we present a comparison between Brillouin and Rayleigh scattering measurements, and their accuracy, and highlight the importance of temperature and strain separation. We also present several important applications in large scale civil engineering infrastructure projects.

Optical Fibre-Based Sensors—An Assessment of Current Innovations

“…Since the 1980s, the use of fibre-optic sensors has steadily expanded across a range of applications. The underlying sectors have seen considerable advancements in distributed fibre-optic sensors, which provide continuous and real-time measurements over the whole length of an optical fibre cable [ 54 ]. Distributed fibre-optic sensors have substantial value throughout a well’s life cycle and may monitor pipelines that carry hydrocarbons over long distances in the oil and gas industry [ 55 ].…”

“…Distributed fibre-optic sensors have substantial value throughout a well’s life cycle and may monitor pipelines that carry hydrocarbons over long distances in the oil and gas industry [ 55 ]. Distributed fibre optic sensors have several advantages over traditional electromechanical-based sensors used in the environmental, mining, civil, and geo-energy fields, particularly for harsh and difficult-to-access conditions [ 54 , 56 , 57 , 58 ]. These advantages include light weight, small size, electromagnetic interference immunity, remote detection, resistance to high pressure and high temperature, multiplexing, and smart sensing.…”

Classification of Events Violating the Safety of Physical Layers in Fiber-Optic Network Infrastructures

“…These systems are very accurate and enable localization of events and measurements over long distances, while being complex, robust, and costly [ 3 , 10 ]. Consequently, these systems are often used to secure critical infrastructures [ 11 , 12 ].…”

Pilot-scale testing of natural gas pipeline monitoring based on phase-OTDR and enhanced scatter optical fiber cable

“…Among various distributed fiber sensor systems, a phase-sensitive optical time domain reflectometer (Φ-OTDR) is the most novel technique for real-time acoustic vibration measurement with high sensitivity and spatially resolved sensing 7 . However, when using conventional fibers the sensing performance is severely degraded due to low backscattered intensity level, thus limited sensitivity and performance for pipeline monitoring applications 8 . Moreover, Φ-OTDR sensing performance is severely degraded by interference and polarization fading.…”