Building vibrations caused by heavy traffic close to buildings in urban areas were investigated at four sites where a high degree of vibration bother had been demonstrated or was expected. It was found that low frequency acoustic excitation was responsible for floor vibrations at all sites. Floor vibrations were generated in two frequency ranges. These were 63 - 125 Hz which corresponded with the excitation frequencies of exhaust emissions, and at 10 to 25 Hz which corresponded with the natural frequencies of the upper freely-suspended floors at the sites. The use of vibration perception thresholds to describe criteria for bother is discussed. It is suggested that the mechanism of vibration disturbance may be a complex combination involving structural vibration and low frequency sound which may be either heard or felt as body vibration. (Author/publisher)
Abstract