Experimental Analysis of Steel Beams Subjected to Fire Enhanced by Brillouin Scattering-Based Fiber Optic Sensor Data

Huang

et al. 2019

Sensors

Self Cite

Reliable and accurate measurements of temperature and strain in structures subjected to fire can be difficult to obtain using traditional sensing technologies based on electrical signals. Fiber optic sensors, which are based on light signals, solve many of the problems of monitoring structures in high temperature environments; however, they present their own challenges. This paper, which is intended for structural engineers new to fiber optic sensors, reviews various fiber optic sensors that have been used to make measurements in structure fires, including the sensing principles, fabrication, key characteristics, and recently-reported applications. Three categories of fiber optic sensors are reviewed: Grating-based sensors, interferometer sensors, and distributed sensors.

Section: Distributed Fiber Optic Sensorsmentioning

confidence: 99%

Section: Distributed Fiber Optic Sensorsmentioning

confidence: 99%

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Review of Fiber Optic Sensors for Structural Fire Engineering

Huang

et al. 2019

Sensors

Self Cite

“…Different distributed sensors have been used to measure temperatures in small-scale steel and reinforced concrete beams subjected to fire. For example, temperature distributions of a small steel beam exposed to combined fire and mechanical loading were measured and enabled an enhanced thermal–mechanical analysis of the steel beam [ 21 ]; In addition, temperature distributions in a small reinforced concrete beam exposed to fire were measured and enabled detection of cracks in the concrete [ 22 ]. Based on the existing studies, it is rational to hypothesize that distributed fiber optic sensors can be deployed in structures to image three-dimensional temperature distributions and generate digital models of these distributions.…”

Section: Introductionmentioning

confidence: 99%

Measuring Three-Dimensional Temperature Distributions in Steel–Concrete Composite Slabs Subjected to Fire Using Distributed Fiber Optic Sensors

Smith

et al. 2020

Sensors

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Detailed information about temperature distribution can be important to understand structural behavior in fire. This study develops a method to image three-dimensional temperature distributions in steel–concrete composite slabs using distributed fiber optic sensors. The feasibility of the method is explored using six 1.2 m × 0.9 m steel–concrete composite slabs instrumented with distributed sensors and thermocouples subjected to fire for over 3 h. Dense point clouds of temperature in the slabs were measured using the distributed sensors. The results show that the distributed sensors operated at material temperatures up to 960 °C with acceptable accuracy for many structural fire applications. The measured non-uniform temperature distributions indicate a spatially distributed thermal response in steel–concrete composite slabs, which can only be adequately captured using approaches that provide a high density of through-depth data points.

“…Thus, a pulse pre-pump BOTDA (PPP-BOTDA) has recently been developed and commercialized with spatial resolution of 2 cm over a measurement distance of 0.5 km [20, 21]. PPP-BOTDA sensors for strain and temperature measurement at elevated temperatures were characterized [22–24], and implemented the sensors for steel beams in fire [25]. With an annealing treatment, the maximum operation temperature has been extended to 1000 °C [26].…”

Section: Introductionmentioning

confidence: 99%

Temperature measurement and damage detection in concrete beams exposed to fire using PPP-BOTDA based fiber optic sensors

Smith

et al. 2017

Smart Mater. Struct.

Self Cite

In this study, distributed fiber optic sensors based on pulse pre-pump Brillouin optical time domain analysis (PPP-BODTA) are characterized and deployed to measure spatially-distributed temperatures in reinforced concrete specimens exposed to fire. Four beams were tested to failure in a natural gas fueled compartment fire, each instrumented with one fused silica, single-mode optical fiber as a distributed sensor and four thermocouples. Prior to concrete cracking, the distributed temperature was validated at locations of the thermocouples by a relative difference of less than 9 %. The cracks in concrete can be identified as sharp peaks in the temperature distribution since the cracks are locally filled with hot air. Concrete cracking did not affect the sensitivity of the distributed sensor but concrete spalling broke the optical fiber loop required for PPP-BOTDA measurements.