Parametric Study of Traffic Induced Ground Vibrations due to Heavy Vehicles

Abstract

Due to recently imposed building regulations the demands of sound exposure levels to buildings have changed, allowing urban planners to design residential areas in direct proximity to roads and railways. While the Swedish building code requires for a risk evaluation regarding comfort vibrations when a railway is in adjacency to the area under consideration it neglects the contribution from heavy vehicles such as trucks and buses. Nevertheless, when a building stands finish a certain vibration level may not be exceeded, independent of the source of vibrations. This issue is presently approached by using doubtful reference values for transfer factors from ground to building which are based on personal experience and measurements conducted with trains as the source of excitation. This thesis examines the induced vibration levels from heavy vehicles by modelling ground and buildings together in finite element models. Using an experimental and numerical approach, ground induced vibrations are measured from an arbitrary heavy vehicle and then used for validation of the finite element model which acts as the base of the parametric study. Investigated parameters are diverse types of foundationsi.e. framefoundations,basementfoundationandpilingfoundationwith varying static loads, sizes and thicknesses. The results show that presently used reference values overestimate the impact of some structural measures for vibration transfer reduction while neglecting important factors such as the static load on the foundation and the size of the building. Themosteffectivestructuralcounter-measureprovedtobeapilingfoundationhowever its efficiency is highly dependent on the density of the piling-grid. Further, the parametric study showed no significant difference between a basement foundation and a slab on grade foundation.