Effect of Walking people on Dynamic Properties of Floors

Despite the intensive research that has focused on the dynamic interaction between walking people and slender footbridges, this phenomenon has never been investigated for floor structures. For lightweight floors having mass of 150 kg/m(2) or less, where they have relatively low modal masses and damping ratios, this interaction is expected to be more effective than that for normal floors. Such phenomenon, if proven to exist for floors, could explain one of the reasons behind the discrepancy between the measured vibration response of floors due to human walking and the corresponding predicted responses using the currently available models which neglect human-structure interaction for walking humans. This paper presents the first attempt to investigate the effect of walking people on the dynamic properties of floors. It is based on several experimental tests for groups of people walking on a full-scale but slender laboratory floor structure. For each experiment, a modal test was carried out to identify the dynamic properties of the tested floor. The results showed a significant increase in modal damping for the first vibration mode, while higher modes exhibited less damping increase. A slight increase was also noticed in the natural frequency of the observed modes. These changes in the modal properties are in line with previous observations of the effects of walking people on footbridges. The results presented in this paper can pave the way for future research to model the interaction between walking people and the supporting floor structures in the context of their vibration serviceability. (C) 2017 The Authors. Published by Elsevier Ltd.