Laserfiche WebLink
AMERICAN ENGINEERING TESTING, INC. AET Project No. 22-00012 <br /> The factor of safety with respect to the ultimate soil bearing capacity for these designs would <br /> exceed 3. Based on this design, we estimate that total post-construction building settlement <br /> would not exceed 1 inch, with differential settlement less than 1/2 inch over a horizontal distance <br /> of 30 feet. <br /> 6.4 Floor Slab Design <br /> We recommend using imported select granular soils with less than 20% passing the No. 200 <br /> sieve (such as Mn/DOT 3149.2B1) as interior backfill around the new foundations and in <br /> underslab utility trenches inside the buildings, for relative ease of compaction in confined spaces. <br /> Cohesive or semi-cohesive soil or cobbles/boulders should not be used for this backfill. <br /> The backfill should be placed in lifts, with each lift mechanically compacted using manually- <br /> operated vibratory or impact equipment, to at least 95% of the maximum Standard Proctor dry <br /> density. The fill should be placed in lifts thin enough to attain the specified compaction level <br /> throughout the entire lift thickness. This normally requires that fill be placed in loose lifts less <br /> than 8 inches thick. <br /> We recommend not using heavy towed or self-propelled compactors within 4 feet of newly <br /> constructed foundation walls, including loading dock walls; such equipment can damage the new <br /> walls. Based on a subgrade prepared with this type of backfill, and after general site grading,the <br /> floor slab can be cast on-grade. For slabs cast on new compacted granular fill, we recommend <br /> using a modulus of subgrade reaction (k) of 250 pounds per cubic inch (pci) for design of the <br /> slabs; for slabs cast on clay fill,we recommend using a k value of 125 pci. If aggregate piers are <br /> used to improve the floor slab subgrade, we recommend using a k value of 150 pci for design of <br /> the slabs. <br /> We recommend that a vapor retarder be placed over the subgrade to reduce the potential for <br /> moisture migration. Moisture migration up to and through the concrete slab can damage coatings <br /> Page 16 of 28 <br />