Ventilator jet fan is installed in long tunnels to ventilate exhaust gas of the vehicles. The jet fan is hung on the ceiling of the tunnels using turn buckles. The accessibility of the jet fan is limited and this causes high cost for safety inspections. Due to the accessibility, inspection intervals are decided by only running time. However, accidents of the jet fan are suddenly caused by an impact of large vehicles or a change of environmental condition. These accidents cannot be detected with a present time based inspection. To solve these issues, real time monitoring system for the jet fan is required. In this study, for basic study of automatic damage monitoring method, vibration analysis for damage monitoring of the jet fan was conducted.
