Fiber Bragg Grating
The FBG technology has great characteristics for both the multiplexing capability as well as self-referencing. Several sensors, with different functions, can be connected in series on a single fiber without signals being confused. The necessary cable length becomes considerably smaller because of this technology. The connection between the measurement unit and sensors are ensured via standard telecommunication fibers. A distance of several tens of kilometers can be reached. Therefore you can cover a large area to measure without the need of additional equipment and a power connection on all measurement locations. For each grating a reflected wavelength, which is an absolute parameter, is defined. This means there is the possibility of turning off or changing the measurement unit without the need to perform a static calibration or determining a new zero value. Looking at the explanation above, we can easily say that by implementing our Structural Health Monitoring solution the safety of the tunnel will improve and because of the collected data the predictability of maintenance can be reached. This represents both a public as well as a economic goal.