B. Test in a real environment
The real environment is characterized by a metal bridge with approximately 40 m long. The bridge and examples of FBG sensors deployed along this structure are shown in Figure 10. An optical cable of approximately 500 m connects the sensor network installed on the bridge with the interrogator located in the laboratory. The SHM of the structure is continually carried out by an optical sensor network composed of three temperature sensors, three strain sensors and five acceleration sensors. The strain sensors were installed on positions defined and always accompanied by a temperature sensor. These temperature sensors are located closest to the strain sensors for the purpose of compensation. The accelerometers were previously assembled at their bases in uni, bi or triaxial mount in order to be able to easy installation and removal.