Fernandez Ignasi, Berrocal Carlos G, Rempling Rasmus
Division of Structural Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden.
Thomas Concrete Group AB, Södra Vägen 28, 41254 Göteborg, Sweden.
Sensors (Basel). 2021 Sep 22;21(19):6338. doi: 10.3390/s21196338.
This paper explores the performance of distributed optical fiber sensors based on Rayleigh backscattering for the monitoring of strains in reinforced concrete elements subjected to different types of long-term external loading. In particular, the reliability and accuracy of robust fiber optic cables with an inner steel tube and an external protective polymeric cladding were investigated through a series of laboratory experiments involving large-scale reinforced concrete beams subjected to either sustained deflection or cyclic loading for 96 days. The unmatched spatial resolution of the strain measurements provided by the sensors allows for a level of detail that leads to new insights in the understanding of the structural behavior of reinforced concrete specimens. Moreover, the accuracy and stability of the sensors enabled the monitoring of subtle strain variations, both in the short-term due to changes of the external load and in the long-term due to time-dependent effects such as creep. Moreover, a comparison with Digital Image Correlation measurements revealed that the strain measurements and the calculation of deflection and crack widths derived thereof remain accurate over time. Therefore, the study concluded that this type of fiber optic has great potential to be used in real long-term monitoring applications in reinforced concrete structures.
本文探讨了基于瑞利背向散射的分布式光纤传感器在监测承受不同类型长期外部荷载的钢筋混凝土构件应变方面的性能。具体而言，通过一系列实验室试验，对带有内部钢管和外部保护性聚合物包层的坚固光缆的可靠性和准确性进行了研究，这些试验涉及对大型钢筋混凝土梁施加持续挠度或循环荷载达96天。传感器提供的应变测量具有无与伦比的空间分辨率，能够达到一定的详细程度，从而为理解钢筋混凝土试件的结构行为带来新的见解。此外，传感器的准确性和稳定性使得既能监测由于外部荷载变化导致的短期细微应变变化，也能监测由于徐变等时效效应导致的长期细微应变变化。此外，与数字图像相关测量的比较表明，应变测量以及由此得出的挠度和裂缝宽度计算随时间推移仍保持准确。因此，该研究得出结论，这种类型的光纤在钢筋混凝土结构的实际长期监测应用中具有巨大潜力。
