8.3 SR 04-04-2022 - Laserfiche WebLink

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March 2, 2020 Project 19-460 Jackson Hills Residential Suite Phases II- IV Elk River, Minnesota The buildings will be three story, at -grade, wood framed structures placed on standard spread footings. We assume the site will be raised a few feet, resulting in the wall footings for the building being placed at 1 foot above to one foot below existing ground level. Maximum foundation loads could be expected to be in the range of 6-7 kips per linear foot for wall footings and 100-160 kips for column loads. We recommend all the fill in the proposed soil correction area consist of clean coarse sand or sand and gravel mix with less than 5% passing a number 200 sieve and less than 50% passing a number 40 sieve. All fill in the building and oversizing areas should be compacted to a minimum of 100% of standard proctor maximum density. We recommend the site be dewatered with a series of well points for the entire duration of the soil correction. D. Recommendations The following recommendations are based on our understanding of the proposed project. If our understanding of the project is not accurate, or if changes are made to the project scope, please inform us so that our recommendations can be amended, if necessary. We have included recommendations regarding earthwork and construction that may help in cost estimates and aid in design. We should be allowed to review the proposed construction plans to provide further detailed recommendations, if necessary. Without the opportunity to review the final construction plans, the recommendations made in this report may no longer be valid. Site Grading: We recommend that the existing peat (PT) and organic silt (OL) material be completely removed from the construction area and be replaced with clean, coarse, free draining material. We estimate that this will require an excavation of approximately 2.0 to 14.0 feet across this site. Any peat and organic soils should be wasted or used as landscape material. The excavation should extend to inorganic, competent natural mineral soils consisting of poorly graded sands (SP) or poorly graded sands with silt (SP-SM). Since the bottom of the excavation will be wet, we recommend the contractor use a large enough excavator to be able to remove the organic soils and backfill quickly to avoid collapse of the excavation sidewalls prior to backfilling. We recommend the excavation proceed across in strips narrow enough to be backfilled promptly. We recommend all backfill consist of clean coarse sand or sand and gravel mix with less than 50% passing a 940 sieve and less than 5% passing a 9200 sieve. The contractor should be well experienced in this type of operation. Page 5