GeoTech Report_8267 Big Spring VA - CLC Phase 3.pdf

This is a Geotechnical Investigation Report for the CLC Phase 3 project at the VA Medical Center in Big Spring, Texas, prepared by Enprotec/Hibbs & Todd, Inc. The investigation was authorized in April 2022 and provides foundation and floor slab design information along with construction recommendations for a proposed single-story building of approximately 7,500 square feet with steel framing and brick veneer.

The site is underlain by moderate strength, low expansive sandy clays further underlain by clayey and silty sands and cemented sands. The Potential Vertical Rise (PVR) is estimated to be less than one-half inch. Foundation design recommendations include a shallow foundation system with continuous wall footings for load-bearing walls and spread footings for building columns, designed for maximum net allowable bearing pressures of 2.5 to 3.0 kips per square foot based on dead load plus design live load. The slab-on-grade should be supported on properly compacted existing soils or select fill used to raise site grades to provide a PVR of less than one-half inch, with a minimum 5-inch thick concrete slab reinforced with #4 rebar 18 inches on center. Critical construction recommendations include site clearing requiring removal of moderately organic topsoil and Portland cement concrete pavement; proofrolling to locate soft or unstable areas; compaction of select fill to minimum 95 percent Standard Proctor density at not less than 2 percent below optimum moisture content; installation of a vapor barrier below the slab-on-grade in moisture sensitive areas; excavation observation by a geotechnical engineer; and utility trench plugging with low permeability materials. The report specifies minimum testing and sampling frequencies during construction including Proctor tests, Atterberg limits tests, and concrete cylinder testing.