7.2. HRSR 08-02-2021 - Laserfiche WebLink

Home Browse Search

Preliminary Report of Geotechnical Exploration Main & Gates Redevelopment; Elk River, Minnesota AMERICAN July 9, 2021 ENGINEERING Report No. P-0001445 TESTING, INC. Page 7 of 10 inches for column footings and a minimum width of 24 inches for strip footings to avoid disproportionately small footing sizes. All foundation bases should be surface compacted with a large plate compacter or vibratory roller prior to foundation placement. Some wetting of the foundation base soils may be necessary if the sand soils are in a dry condition. 6.4 Floor Slab Design After completion of the earthwork recommended above, it is our judgement that the floor slab can be supported by the new compacted engineered fill soils. For constructability purposes, we recommend placement at least 4 inches of Class 5 aggregate base (meeting MnDOT Specification 3138) immediately below the floor. We recommend designing the floor slab using a Modulus of Subgrade Reaction (k-value) of 175 pci if placed on at least 4 inches of aggregate base. If at least 6 inches of aggregate base is constructed, a k-value of 200 pci should be used for slab design. The use of certain types of flooring may require the installation of moisture/vapor membranes below the floor slab. Typically, if moisture sensitive floor coverings like tile or carpet will be used, moisture/vapor membranes are recommended. Most floor covering manufacturers require that the vapor retarder be placed directly below the concrete slab for warranty purposes. For recommendations pertaining to moisture and vapor protection of interior floor slabs, we refer you to the attached standard sheet entitled “Floor Slab Moisture/Vapor Protection.” 6.5 Basement Backfilling/Water Control Our recommendations for backfilling the basement walls appear on the attached standard sheet entitled “Basement/Retaining Wall Backfill and Water Control.” To avoid water intrusion issues into the basement, it will be very important that these details be incorporated into the design, and that construction monitoring be performed to assure that proper materials and construction is implemented. We recommend the installation of drain tiles around the perimeter of the below-grade walls, at bottom-of-footing elevation, be included in the design. The drain tiles should be routed to sump pits or to the sewer system (if local ordinances allow) for discharge of the collected water. If the design elevation of the basement is within 3 feet of the groundwater level we recommend that Draft