I need a PLAXIS 3D workflow that lets me study how a multi-layer stack—concrete on top of several supporting layers—responds to two load cases: everyday footfall and a separate, uniform static pressure. For the first pass I want to model the structure with the smaller-dimension option, then compare the response to the current standard sizing I already have in house. Your task is to walk me through the entire numerical set-up so I can run both variants with confidence and extract the key response plots. The dynamic footfall study must explicitly cover: • Force impact • Frequency of footfall • Distribution of load Please lay out: • Recommended element choices, boundary conditions and mesh density for a layered concrete system. • Material models, damping values and any strain-dependent parameters that are critical when concrete is the governing layer. • How to combine the time-history footfall loading with the steady uniform pressure in the same stage sequence. • Output checks (settlements, tensile stresses, vibration levels) that confirm the model is behaving as expected. Deliver the PLAXIS project file(s) plus a concise setup note so I can rerun the scenarios and swap dimensions later without starting from scratch.