Transmission of Vibration into Vibration-Isolated Buildings

Abstract

Buildings constructed above or near underground and surface roads and railways often include some type of vibration isolation in their foundations. The effectiveness of such isolation measures is usually calculated by treating the building as a rigid block and the resulting mass-spring-damper system as a single-degree-of-freedom oscillator whose characteristic response to vibration is well known. Measurements in isolated buildings show that the truth is far more complicated and that the simple model is of no use whatsoever for predicting vibration levels. In this paper, simple alternative models of buildings will be presented and methods of interpretation of measured vibration spectra in the light of coherence functions for multi-input multi-output systems will be discussed.