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, Hennepin Parks <br /> Project BABX-91-589 <br /> December 19, 1991 <br /> ' Page 7 <br /> , <br /> ' C.S.b Desi n Sections: We have assumed onl li h <br /> g y g t car tra�c with no heavy trucks to be <br /> ' using these pazking and drive areas. For the above subgrade and the assumed traffic, we <br /> recommend a minimum of 2 inches of Mn/DOT 2341 weaz over 8 inches of crushed <br /> aggregate base. <br /> 1 <br /> � D. Construction <br /> D.1 Excavation <br /> ' Because of the potential for high groundwater, it is our opinion the soils neaz the bottom of <br /> any excavation may not be able to support rubber-tired equipment. We therefore recommend <br /> , that low ground pressure tracked equipment or a backhoe be used to perform the needed <br /> excavations. <br /> ' D.2 Observations _ <br /> We recommend that all excavation, footing, slab and pavement subgrades be observed by a <br /> ' geotechnical engineer to evaluate if the subgrade soils are similar to those encountered by the <br /> borings, adequate to support the proposed construction and adequately oversized. These <br /> observations should be conducted prior to placing backfills, fills or forms for footings. . <br /> 1 <br /> After excavating for footings, we recommend that tests be conducted on the subgrades to <br /> ' evaluate if the bearing capacity is at least 2,000 psf. Typical instruments used for these tests <br /> include hand augers, penetrometers and sample tubes. <br /> , D.3 Backfills and Fills � <br /> Site soils which will be excavated and potentially reused as backfill and general site fill appeaz <br /> ' to be wet of the optimum moisture content. We anticipate it will be necessary to dry these <br /> soils to achieve the recommended compaction. We recommend the fill and backfill be placed <br /> in lifts not exceeding 8 to 12 inches, depending upon the size of the compactor and material <br /> ' used. <br /> ' � <br /> 1 <br /> ' <br />