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Bremer Financial Corporation <br />Project B2008939 <br />November 17, 2020 <br />Page 12 <br /> <br /> <br /> <br />An OSHA-approved qualified person should review the soil classification in the field. Excavations must <br />comply with the requirements of OSHA 29 CFR, Part 1926, Subpart P, “Excavations and Trenches.” This <br />document states excavation safety is the responsibility of the contractor. The project specifications <br />should reference these OSHA requirements. <br /> <br />C.2.d. Excavation Dewatering <br />Groundwater is anticipated to be below excavation depths , however water may collect in excavations <br />from precipitation or surface runoff. The contractor should assume any collected water within <br />excavations should be immediately removed to facilitate construction and proper backfilling. We would <br />assume conventional sumps could control the water in most excavations. <br /> <br />C.2.e. Pavement and Exterior Slab Subgrade Preparation <br />We recommend the following steps for pavement and exterior slab subgrade preparation . Note that <br />project planning may need to require additional subcuts to limit frost heave. <br /> <br />1. Strip unsuitable soils consisting of topsoil, organic soils, vegetation, ex isting structures and <br />pavements from the area, within 3 feet of the surface of the proposed pavement grade. <br />2. Have a geotechnical representative observe the excavated subgrade to evaluate if additional <br />subgrade improvements are necessary. <br />3. Slope subgrade soils to areas of sand or drain tile to allow the removal of accumulating <br />water. <br />4. Surface compact the subgrade with several passes of a large self -propelled vibratory, drum <br />roller. <br />5. Place pavement engineered fill to grade and compact in accordance with Section C.2.g to <br />bottom of pavement and exterior slab section. See Section C.6 for additional considerations <br />related to frost heave. <br />6. Proofroll the pavement or exterior slab subgrade as described in Section C.2.f. <br />To improve long-term pavement performance, we recommend incorporating 18 inches of non-frost- <br />susceptible engineered fill in paved areas, in addition to the recommendations above, as a sand subbase. <br />Section C.7 provides recommended pavement design sections with and without the sand subbase. Note, <br />we recommend sloping subgrade soils to promote drainage and removal of accumulated water.