EVALUATION OF MATHEMATICAL MODELS FOR PREDICTING WALKING-INDUCED VIBRATIONS OF HIGH-FREQUENCY FLOORS

Abstract

This paper evaluates performance of three representative single-person walking excitation models which can be used to check vibration levels of high-frequency building floors accommodating highly sensitive equipment. The three models calculate vibration responses by harmonic, transient and spectral analyses, respectively. The evaluation was based on a combined experimental and analytical work comprising modal testing of a prototype floor, repeated measurements of walking-induced vibrations, finite element modelling and model updating to match the measured modal properties. The updated and verified model was then used for the application of the three walking models results of which were then compared with their experimental counterparts. It was found that all three models were on the "safe" side and overestimated responses measured in all response tests. However, the harmonic model which assumes high-frequency floor resonance caused by the 7th or 8th harmonic of the walking resulted in over-conservative response estimates order of magnitude higher than the maximum measured values in all response tests. Nevertheless, the model which describes walking across a high-frequency floor as pulses representing footfalls consistently overestimated responses by just about 20% and is, therefore, recommended for vibration serviceability checks of this type of floors.