Analysis of the cause of noise when the drawbridge goes up and down through non‐destructive diagnosis.

In the case of the Yeongdodaegyo bridge, abnormal noise occurred only in summer when it was opened, and the expected cause of noise was expected to be due to bearing damage or deformation friction. Therefore, a non‐destructive test was performed around the spherical bearing, which is a major part of the drawbridge components connected to the rotating shaft girder. For the measurement to analyze the cause of noise, the real‐time noise source was tracked during hoisting using an acoustic sensor according to the angular displacement of the rotating shaft. Through this, we tried to identify the noise source by identifying the left and right real‐time deformation (torsion, deflection, inclination) and the friction part of the damaged bearing. As a result of the analysis, irregular noise was generated from the left and right sides, and noise was generated when the twist, deflection, or tilt of the rotation shaft occurred. The bottom of the left and right bearings was found to be the main source of noise, and the bearing contact during deformation is considered to be the cause of the noise. [ABSTRACT FROM AUTHOR]