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Bremer Financial Corporation <br />Project B2008939 <br />November 17, 2020 <br />Page 21 <br /> <br /> <br />developing a regular maintenance plan for filling cracks in exterior slabs and pavements to lessen the <br />potential impacts for cold weather distress due to frost heave or warm weather distress due to wetting <br />and softening of the subgrade. <br /> <br />C.8. Utilities <br /> <br />C.8.a. Subgrade Stabilization <br />Earthwork activities associated with utility in stallations located inside the building area should adhere to <br />the recommendations in Section C.2.g. <br /> <br />For exterior utilities, we anticipate the soils at typical invert elevations will be suitable for utility support. <br />However, if construction encounters unfavorable conditions such as soft clay, organic soils or perched <br />water at invert grades, the unsuitable soils may require some additional subcutting and replacement <br />with sand or crushed rock to prepare a proper subgrade for pipe support. Project design and construction <br />should not place utilities within the 1H:1V oversizing of foundations. <br /> <br />C.8.b. Corrosion Potential <br />Based on our experience, the soils encountered by the borings are moderately corrosive to metallic <br />conduits, but only marginally corrosive to concrete. We recommend specifying non-corrosive materials <br />or providing corrosion protection, unless project planning chooses to perform additional tests to <br />demonstrate the soils are not corrosive. <br /> <br />C.9. Stormwater <br /> <br />We estimated infiltration rates for some of the soils we encountered in our soil borings, as listed in <br />Table 9. These infiltration rates represent the long-term infiltration capacity of a practice and not the <br />capacity of the soils in their natural state. Field testing, such as with a double-ring infiltrometer (ASTM <br />D3385), may justify the use of higher infiltration rates. However, we recommend adjusting field test rates <br />by the appropriate correction factor, as provided for in the Minnesota Stormwater Manual or as allowed <br />by the local watershed. We recommend consulting the Minnesota Stormwater Manual for stormwater <br />design. <br /> <br />