2001 Geotechnical Evaluation Report

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B R A U NSM Braun Intertee Corporation 6801 Washington Avenue South Minneapolis,Minnesota 55439 INTE RT E C 612-941-5600 Fax:941-4151 Engineers and Scientists Serving the Built and Natural Environment? April 12, 2001 Project BABX-01-0124 Mr. Rick Vogelgesang RVC Homes 900 Twelve Oaks Center Drive Minnetonka, MN 55391 Dear Mr. Vogelgesang: Re: Geotechnical Evaluation, Proposed House at 1080 Wildhurst Trail, Orono, Minnesota As you authorized, we have completed the geotechnical evaluation for the proposed house at 1080 Wildhurst Trail in Orono, Minnesota. The purpose of the geotechnical evaluation was to assist in evaluating the subsurface soil and groundwater conditions with regard to construction of the house. Our work was performed in general accordance with the Authorization of Services you signed. Summary of Results The two borings performed on this site, and the two borings performed in the neighboring lot, indicate soil conditions generally consist of old fill soils over soft, compressible organic soils to depths of about 19 to 35 feet. Excavations in excess of 15 feet are typically not economical, and in this case high groundwater would cause extreme difficulty and may prevent successful excavation of unstable soils. Summary of Recommendations If the new house is constructed where it is currently designed to be, we recommend the house and floor slab be designed to be supported by a deep foundation system consisting of closed-end driven pipe piling. Due to the depths of soft organic soils, it is our opinion an excavate backfill approach would not be feasible. Due to the high groundwater, we recommend the lowest floor slab elevation be at 933 or about 4 feet above the estimated static groundwater table. We recommend considering using a moisture barrier under the floor slab. We recommend the pile caps, grade beams, and foundation walls be backfilled with a clean granular material to reduce the potential effects for negative loading related to settlement. We also recommend the exterior features such as drive apron, sidewalks and landscaping be designed to tolerate settlement. If a raise in grade of more than a few feet is made, we recommend surcharging the new fill and/or delaying construction of these non-pile supported elements and monitoring settlement during a period of time. Completion of exterior features such as slabs, sidewalks, and drive aprons may have to wait until induced settlement significantly slows.