Wilco Farm Store

Scope of Work:

This project involved the development of a 3,000 square foot building addition to an existing location of the Wilco Farm Store retail chain, construction of a new standalone 1,800 square foot storage structure, and reconstruction of a section of paved parking lot elsewhere on the project site. Located in the Willamette River Basin, preliminary geological mapping review of this area indicated that the project site is typically underlain by fine grained soils.

Our team logged soil, rock, and groundwater conditions that were encountered during drilling, classified in general accordance with the Unified Soil Classification System. We found that the in-situ soil layers layer of Missoula Flood Deposit overlain by unknown fill. After soil samples were collected, laboratory tests were completed to determine the engineering properties of the soil.

Visiting the site during the construction phase, our team used standard engineering soil probes to gauge the competency of the exposed subgrade material. Overexcavation and installation of engineered structural fill was required in structural areas for the standalone storage structure, and our in-house laboratory testing was able to inform us that the crushed aggregate being used in reconstruction of the parking area’s sub-base rock was not prepared to our recommendations. Working with the contractor, we were able to alleviate these issues resulting in a broader scope of work than originally anticipated, but constant communication with the client allowed us to proceed knowing that they were happy with the achieved results.



  • Wilco was able to complete their project as designed despite adverse weather conditions during construction
  • Increased level of communication with client as required, resulting in a positive relationship                                                                                                                       


The geotechnical report Central Geotech provided included (but was not limited to):

  • Recommendations for site preparation, grading, fill placement, compaction criteria, drainage and wet-weather earthwork procedures
  • Design criteria for cast-in-place embedded building walls including lateral earth pressures, base friction, drainage, backfill material and compaction
  • General seismic design criteria in accordance with the Oregon Structural Specialty Code