NUMERICAL MODELLING OF THE GROUND-BORNE VIBRATIONS GENERATED BY TRUCK-ROAD INTERACTION

Like railway-induced ground vibrations, ground-borne motions generated by the passing of heavy vehicles in urban areas are one of the fundamental problems in transport annoyance in the vicinity of buildings. In presence of local geometries like a speed bump or pavement defects, wheels interact with the road surface and cause dynamic motions in the vehicle that reacts with the road and generates high level vibrations that propagate in the soil through complex waves and impinge on the foundations of nearby structures. The scope of this study is twofold. The first part is dedicated to the prediction of vibration levels using a two-step approach. A multibody approach is used for the vehicle modelling, including the tyre/bump/road interaction. A finite element analysis is used for the next approach, calculating the ground wave propagation of a moving load, defined as the output of the first calculation. A decoupled simulation is possible due to the large stiffness of the road compared to the stiffness characteristics of the vehicle (tyre). A validation is performed using experimental data available in the literature. The second part focuses on a sensitivity analysis in order to identify the main parameters (bump geometry, speed,...) that affect the shape and level of peak particle velocity at various distances from the road. In light of the study, the prediction scheme offers an efficient way to design speed bumps and to understand the complex waves generated by a transient moving load propagating in an infinite medium.