Prudent Commercial Real Estate (CRE) Investments normally require soil studies completed as part of feasibility period or building dept. submittals. The soil analysis is vital information for the structural engineer to determine thickness of slab and footings, etc..
Below is actual report findings from the above video. It was good day of drilling as the data discovery showed favorable soil for intended 8-story building.
Soil examination report: In summary, the test borings we completed at the site encountered competent soils at shallow depths. Groundwater was observed at depths of 11 and 15 feet below ground surface in the two test borings completed in the lower portion of the site (i.e., near Rainier Avenue South). The observed groundwater is below the anticipated footing elevations. In our opinion, the proposed building can be supported on conventional footings bearing on competent native soils or on structural fill used. Soldier piles with lagging are considered appropriate to support the temporary basement excavation.
Four borings were drilled at the site on July 31, 2017, at the approximate locations indicated on the attached Figure 2. The borings were drilled to a maximum depth of 15½ feet using an Acker hand portable drill rig owned and operated by Boretec, Inc. The borings were logged by a geologist from PanGEO.
Standard Penetration Tests (SPT) were performed at 2½- and 5-foot depth intervals using a standard, 2-inch diameter split-spoon sampler. The sampler was advanced with a 140-pound drop hammer falling a distance of 30 inches for each stroke, in general accordance with ASTM D-1586, Standard Test Method for Penetration Test and Split Barrel Sampling of Soils.
The soils were logged in general accordance with ASTM D-2487 Standard Practice for Classification of Soils for Engineering Purposes and the system summarized on Figure A-1, Terms and Symbols for Boring and Test Pit Logs.
Based on our review of The Geologic Map of Seattle-A Progress Report (Troost et al., 2005), the primary geologic units in the vicinity of the site are recessional outwash deposits (Geologic Map Unit Qvr) and recessional lacustrine deposits (Geologic Map Unit Qvrl). Coarse-grained deposits of pre-Fraser glaciation age (Geologic Map Unit Qpfc) are also mapped about one block south of the site.
Recessional outwash deposits typically consist of loose to dense, moderately- to well-sorted sand and gravel. Recessional lacustrine deposits typically consist of very soft to stiff, laminated silt and clay, with local sand layers, peat, and organic sediments. Pre-Fraser coarse-grained deposits typically consist of very dense, lightly to moderately oxidized, clean to silty sand and gravel, with some silt layers.