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AMERICAN ENGINEERING TESTING, INC. AET Project No. 22-00012 <br /> 6.0 RECOMMENDATIONS <br /> 6.1 Building Pad Preparation Alternative No. 1—Soil Correction <br /> 6.1.1 Excavation <br /> We recommend that the surficial topsoil be stripped from the footprints of the buildings. The <br /> zone of stripping should extend laterally to at least 5 feet beyond the building perimeters. The <br /> topsoil depths ranged from 2 feet to 4.5 feet; this is considered relatively deep and the variance is <br /> up to 2.5 feet. Thus, significant variations in topsoil depths should be anticipated. <br /> Further, below the topsoil in several of the test pits, we observed 0.5 foot to 2 feet of relatively <br /> soft gray lean clay and silt with black organic layers and staining. We recommend that this layer <br /> of clay and silt with organics below the topsoil also be stripped. The excavators bidding this <br /> project should not be allowed to use our borings to calculate topsoil stripping depths and <br /> volumes; they should be required to carry out their own topsoil surveys. <br /> All remnants of the razed structures and utilities should be completely removed from the <br /> footprints of the buildings. We also recommend subcutting the existing fill, buried topsoil, and <br /> any other unsuitable soils that are found in the footprints of the buildings after the topsoil has <br /> been stripped. In the building pads, the lateral zone of subcutting should be extended out <br /> horizontally at least 1 foot from the outside edges of perimeter footings for every foot of fill <br /> required below the base of the footings (i.e., 1:1 lateral oversize). This lateral oversize is to be <br /> measured at the base of the subcut,not at the surface. <br /> The following table presents our estimated depths of stripping/subcutting in the building pads, <br /> based on information from the borings. The actual required depth of stripping/subcutting may be <br /> deeper or shallower than found at the borings. This should be determined by a Geotechnical <br /> Engineer or Technician performing full-time observation and testing during site preparation. <br /> Because of the unknown depths and lateral extent of the subcutting that will be needed, we <br /> recommend that the earthwork contract include a unit price line item for extra soil correction <br /> Page 9 of 28 <br />