Sound field radiated by infinitely long elastic plate strips placed in parallel

With the aim to propose a suitable countermeasure for the elevated structure noise, the sound field radiated by a steel plate girder, which is the main source of the elevated structure noise, have been theoretically analysed to gain a physical insight into the elevated structure noise problem. In actual condition of an elevated motorway, the reflection and diffraction due to the adjacent steel plate girders placed in parallel should be considered for analysis of the sound field. In the present study, the sound field radiated by some steel plate girders are analysed. Steel plate girders are modelled as infinitely long elastic plate strips placed in parallel. In the analysis of the radiated sound field, the equivalent source method is employed. The character of the sound field is discussed thorough numerical examples. The effects of an adjacent steel plate girder on the radiated sound field from a steel plate girder are discussed thoroughly: the adjacent steel plate girder affect significantly the sound field radiated by the plate girder. Especially, the increase of the sound pressure caused by the reflection due to the adjacent steel plate girder is shown. The variations of the effects due to varying number of the girders are also demonstrated.