Citation

Bao Y, Hoehler MS, Smith CM, Bundy M, Chen G. Smart Mater. Struct. 2017; 26(10): PPP-BOTDA.

Affiliation

Department of Civil, Architectural, and Environmental Engineering, Missouri University of Science and Technology, 1401 N. Pine Street, Rolla, MO 65409.

Copyright

(Copyright © 2017, Institute of Physics Publishing)

DOI

10.1088/1361-665X/aa89a9

PMID

29230083

PMCID

PMC5721354

Abstract

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.

Language: en

Keywords

Crack detection; Distributed fiber optic sensor; Fire; PPP-BOTDA; Reinforced concrete; Temperature distribution