Experimental studies on the effect of ceiling materials on the sound environment of underpass concourse using the station simulator

Sound environments in railway stations are often noisy because of sound-reflective materials and many noise sources. Especially in underpass concourses, structure-borne sounds are radiated from the ceiling due to vibrations when trains pass by. This results in a high noise level, which often interferes with listening to the announcements. In this study, to examine interior materials that effectively reduce such noise in railway stations, the following measurements and laboratory experiments were carried out: 1) Field measurements of vibrations of the ceiling and environmental sound in stations in Tokyo. 2) Reproduction of vibrations and sounds in the station simulator (full-scale mock-up of a station building), under the four different types of ceilings. 3) Auditory tests to evaluate the noisiness of train passing sounds and environmental sounds, using reproduced sounds in the station simulator as test sounds. As a result, the ceiling with damping material was effective for structure-borne sound, while the ceiling with porous sound-absorbing material was effective for air-borne sound. This result suggests that it is important to consider the placement of ceiling materials according to the noise situations.