Experiences in Testing Structures with Distributed Fiber-Optical Sensing

In this paper our experiences with distributed fiber-optical strain sensing (DFOS) and temperature measurements are presented for three different projects. Some results of the first project [1] were presented on IOMAC 2022. In 2023 a street equipped with various cable configurations and temperature sensing cables at different layers has been constructed. Temperature and the strain can be measured at different layers. By correlating temperature-adjusted strain values measured in the asphalt pavement and implementing special algorithms, comprehensive conclusions about the street’s condition can be drawn. In a second project the application of DFOS was used in static tests of reinforced concrete elements. Five structural elements were tested until failure. In parallel the specimens were equipped with standard strain gages and several displacement sensors. Different methods were investigated to attach the fibers to the elements and in the elements. The goal of the third project is to use the distributed fiber-optical strain sensing in structural dynamics (OMA) and condition monitoring of steel structures. Simple steel beams were tested in the lab. We hope to gain more experiences so that the distributed fiber-optical strain/temperature method can be applied to bridges and to historical structures.