6.3. SR 02-07-2005 - Laserfiche WebLink

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BRAUN INTERTEC Braun Interlec Corporation 1017 109rh Avenue NE Blaine, MN 55434 Phone 651.4877070 Fox 763 754 2750 VVeb: brounintertec_com December 8, 2004 ProjectBN-04-06875 Mr. Terry Maurer City of Elk River 13065 Orono Parkway Elk River, MN 55330 Dear Mr. Maurer: Re: Geotechnical Evaluation, Proposed 2005 Street Improvements, Elk River, Minnesota. Tue geotechnical evaluation you authorized on October 20, 2004, has been completed. The purpose of the evaluation was to assist you in designing the proposed roadway improvements and in preparing plans and specifications for their construction. The evaluation was performed in general accordance with our October 7,2004, proposal to you. Summary of Results Eighteen standard penetration test borings were completed along the existing alignments. The general soil profile in the borings was approximately 2 to 6 inches of bituminous pavement over about 3 to 8 inches of aggregate base materials. Below the pavement section the borings initially encountered existing fill consisting of mainly of poorly graded sand with silt but areas of silty sand (that locally appeared organic or concealed what appe~ed to be topsoil). The fill was underlain by alluvium consisting of poorly graded sand. Groundwater was generally not observed though four borings in the western portion of the site encountered waterbearing sands at about the 4- to 4 1/2-foot.depths. Summary of Recommendations Both the fill and alluvial soils generally appear suitable for use as roadway subgrade. It appears, however, that these materials may be locally organic, and so we recommend that provisions be made to remove organic soils having an organic content over 5 percent by weight from within 3 feet of subgrade elevation (the botto~ of the aggregate base of the new pavement). To further enhance subgrade strength and uniformity, we recommend surface compacting the exposed subgrade soils prior to placing any additional fill, or the new pavement section. p~ ('lIJii!'.{ dH;i:li..uu~~ iLnd t;."JlI. in.'HmeiHLll '.()[/.lit!:I)]) ~lnt.:! 1957 I I I I I I I I I I I I I I I I I I I