Sound field radiated by an infinitely long elastic plate strip in contact with a vertical reflecting surface

For understanding the phenomenon nature of the elevated structure noise around motorways, theoretical studies concerning the main source are needed. Steel plate girders of elevated motorways are the main source of the elevated structure noise. Considering the real conditions, it is necessary to clarify the effect of a concrete slab on the radiated sound field from a steel plate girder. In the present study, a steel plate girder in contact with a concrete slab is modelled by an infinitely long elastic plate strip in contact with a vertical reflecting surface. The method of equivalent sources is used. The sound field radiated by the elastic plate strip is illustrated by numerical examples. The main effects of a slab on the sound field are discussed. Furthermore, the variation of the effects due to the varying height of a plate girder is demonstrated. It is shown that a concrete slab does not affect significantly the sound field radiated by a plate girder in the range of 500–1000 Hz at most receiving points, which is the frequency range of the main interest in the study on the elevated structure noise.