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Bremer Financial Corporation <br />Project B2008939 <br />November 17, 2020 <br />Page 17 <br /> <br /> <br />C.4.a. Net Allowable Bearing Pressure <br />The aggregate pier designer will determine the allowable soil bearing capacity of footings bearing upon <br />rammed aggregate piers. However, aggregate piers are typically able to support net allowable bearing <br />pressures of 3,000 to 5,000 pounds per square foot (PSF). This value should include a safety factor of at <br />least 3.0 with regard to bearing capacity failure. <br /> <br />C.4.b. Settlement <br />The aggregate pier designer will determine the estimated settlement of footings bearing upon rammed <br />aggregate piers. However, aggregate piers typically limit total and differential settlement of spread <br />footing foundations to less than 1 inch and 1/2 inch, respectively. <br /> <br />C.5. Interior Slabs <br /> <br />C.5.a. Subgrade Modulus <br />The anticipated floor subgrade is engineered fill. We recommend using a modulus of subgrade reaction, <br />k, of 150 pounds per square inch per inch of deflection (pci) to design the slabs . If the slab design <br />requires placing 6 inches of compacted crushed aggregate base immediately below the slab, the slab <br />design may increase the k-value by 50 pci. We recommend that the aggregate base materials be free of <br />bituminous. In addition to improving the modulus of subgrade reaction, an aggregate base facilitates <br />construction activities and is less weather sensitive. <br /> <br />C.5.b. Moisture Vapor Protection <br />Excess transmission of water vapor could cause floor dampness, certain types of floor bonding agents to <br />separate, or mold to form under floor coverings. If project planning includes using floor coverings or <br />coatings, we recommend placing a vapor retarder or vapor barrier immediately beneath the slab. We <br />also recommend consulting with floor covering manufacturers regarding the appropriate type, use and <br />installation of the vapor retarder or barrier to preserve warranty assurances. <br /> <br />C.6. Frost Protection and Exterior Slabs <br /> <br />C.6.a. General <br />Silty sands and clays will underlie all or some of the exterior slabs, as well as pavements. We consider <br />these soils to be moderately to highly frost susceptible. Soils of this type can retain moisture and heave <br />upon freezing. In general, this characteristic is not an issue unless these soils become saturated , due to <br />