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<br /> <br /> <br />Geotechnical Report <br />Arden Oaks Street Improvements <br />Arden Hills, Minnesota <br />WSB Project No. 014297-000 Page 6 <br />these soils should be improved by means of scarification, moisture conditioning, and re-compaction, or by <br />subcutting and replacement. If the on-site soils cannot be moisture conditioned and compacted as <br />recommended, we recommend removing these unsuitable materials and replacing them with Select <br />Grading Material (MnDOT 2105.1.A.6). We also recommend a proof-roll be performed again on the <br />aggregate base just prior to placement of the bituminous pavement. <br /> <br />Table 3 below presents the approximate pavement section thickness and subgrade soils that were <br />encountered within the borings. <br /> <br />Table 3: Roadway Soil Boring Profiles <br />Boring No. <br />Bituminous <br />Thickness <br />(inches) <br />Aggregate <br />Base <br />Thickness <br />(inches) <br />Subgrade Soils <br />(Upper 4 feet) <br />PB-A 5 12 Sandy lean clay <br />PB-B 5 ½ 8 Sandy lean clay <br />PB-C 6 6 Sandy lean clay <br />PB-D 5 8 Sandy lean clay <br />PB-E 6 5 Fill: Sandy lean clay <br />PB-F 6 ½ 7 Sandy lean clay <br />PB-G 5 ½ 5 Fill: Sandy lean clay <br />PB-H 6 13 Fill: Sandy lean clay <br /> <br /> <br />Once the site has been prepared as recommended, we anticipate the subgrade will consist predominately <br />of sandy lean clay. The MnDOT Flexible Pavement Design Guidance Memo from January 2017, <br />indicates soils such as those anticipated have an estimated R-value of 12. <br /> <br />Being traffic counts were not provided to us, we have assumed that the volume and distribution of <br />vehicles using these roadways will have 20-year flexible Equivalent Single Axle Loads (ESAL’s) less than <br />75,000. <br /> <br />Based on MnDOT’s FlexPave excel design utilizing granular equivalent charts, we recommend the <br />pavement sections indicated below in Table 4. <br /> <br />Table 4: Recommended Flexible Pavement Section <br />Section Thickness (inches) Granular Equivalent <br />Bituminous Course, MnDOT 2360 2 4.5 <br />Bituminous Course, MnDOT 2360 2 4.5 <br />Aggregate Base, MnDOT 3138 (Class 5, 5Q, or <br />6) 8 8 <br />Subgrade Preparation, MnDOT 2111 Yes - <br />TOTAL 12 17.0 <br /> <br /> <br /> <br />DRAFT REPORT <br />7-8-2021