Vibration Serviceability of Floors: A Probabilistic Framework

Abstract

Industry feedback and research investigations have reported that problematic vibration responses in floor structures can create significant problems for both their occupants and facility owners. A critical drawback of contemporary design procedures is the lack of realistic loading scenarios and reliable vibration descriptors, since considerable complaints of unpleasant floor vibrations have been reported, even when such guidelines have been employed. A systematic investigation into realistic dynamic loading and patterns of floor occupants is of paramount importance. This thesis investigates and describes a comprehensive procedure to carry out vibration serviceability assessment of floors on the basis of probabilistic design approach. A novel probabilistic walking load model is introduced and developed in this study using individual right and left footfalls. The load model results in more realistic force time histories than \hlcyan{Fourier-based} models, since it incorporates significant components of the spectra that are omitted in Fourier series approaches. Also, the model is applicable for probabilistic designs of multiple pedestrian input forces, regardless of the cut-off frequency. Moreover, a simulation model of spatial distributions of pedestrians is implemented using agent based modelling. This occupant pattern model provides a realistic insight into in-service activities of multiple pedestrians on office floors, in terms of statistical distributions of their walking paths. It was found that the numerical model is capable of mimicking the actual movements to a very good extent, which makes this simulation model ideal for vibration serviceability of floors under footfall excitations. Finally, spatial distribution of vibration responses is calculated using different statistical perspectives integrating both the probabilistic walking load model and spatial distributions of multiple pedestrians. The established approach showed a realistic way of assessing occupant exposure to vibration at specific locations of interest as well as over the entire floor area. This methodology, therefore, is expected to produce a more accurate and reliable assessment of vibration serviceability of floors.