Abstract Summary
From the literature as well as from relevant standards, recommendations for the numerical modelling of soil-structure interaction problems involving seismic actions are well known, e.g. ASCE/SEI 4-16. For human-induced excitations very little specific guidance has been published in the past. However, while in the past FEM software for geotechnical engineering and FEM software for dynamic soil-structure problems were two sets with virtually no intersection, geotechnical FEM software now includes a dynamics feature, while general purpose software has been extended by means to model infinite half spaces. Hence, geotechnical engineering firms have powerful tools to extent their consulting business also into dynamics, and they certainly do. There are, however, many pitfalls when dealing with human-induced vibrations, which are beyond the requirements of seismic analyses. Using the generic example of a machine foundation on a homogeneous half space excited by harmonic loads with excitation frequency between 4 Hz and 64 Hz an extensive sensitivity study on mesh design, frequency domain vs. time domain analysis, time integration procedure and other numerical choices was conducted, which provided guidance on the impact of each of these choices on the vibration amplitude of the foundation as well as the free field. Furthermore, some focus is put on the limits set by the hardware availability in geotechnical consulting firms.
