The World's largest self-supporting enclosed space

This paper considers the problem of human acceptance of floor vibrations induced by walking loads. It defines the parameters used in the assessment of this serviceability issue, including vibration dose values (VDVs) and the frequency weighting that should be applied to vertical vibrations. The relevant guidance given in British Standards is discussed and an example provided to illustrate the analysis procedures. The paper then considers the analysis of measurements of vibration induced by walking, examining first a range of walking frequencies and then deriving some empirical links between measured peak acceleration and VDV. To determine human reaction, VDVs need to be measured for a complete day or night. As this may not always be possible, it is necessary to consider ways of estimating daily VDVs. Therefore, the number of walking periods that should be considered during a day is examined and its influence on the estimated VDVs determined. This provides a relationship between the peak accelerations that can be measured during tests and the VDVs used to assess serviceability. The calculation of VDV is then examined, and calculated VDVs for a range of floors presented. Crowd loading is illustrated using measurements made on two floors. Although the use of VDVs does not seem to have been adopted widely, they appear to provide a sensible method for serviceability evaluation of floor vibrations. Brian R. Ellis, BSc, PhD, CEng, MIStructE Centre for Structural Engineering, BRE, Watford, UK