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.

中文翻译：

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使用基于 PPP-BOTDA 的光纤传感器对暴露在火灾中的混凝土梁进行温度测量和损坏检测

在这项研究中，基于脉冲前置泵布里渊光时域分析 (PPP-BODTA) 的分布式光纤传感器被表征和部署，以测量暴露在火中的钢筋混凝土试样的空间分布温度。四个光束在以天然气为燃料的隔间火灾中被测试为失效，每个光束都配备一根熔融石英单模光纤作为分布式传感器和四个热电偶。在混凝土开裂之前，通过小于 9% 的相对差异验证了热电偶位置处的分布温度。混凝土中的裂缝可以被识别为温度分布中的尖峰，因为裂缝局部充满了热空气。