6107 BERKSHIRE DR 2018-01-02 MF Import

ADaPT Engineering, Inc. Western Wireless Corporation ADaPT Job No, WA98-992 April I, 1998 Page 4 Site Preparation Site preparation will involve essentially stripping, grading, and preparing subgrades. The following comments and recommendations apply to this site preparation: Clearing and Grubbing: We do not anticipate that significant grade changes will be required to achieve proposed site grades. At this location, site preparation will largely consist of removal of surficial vegetation and stripping of clayey topsoil, followed by foundation preparation for the monopole cellular tower and equipment building or cabinets. Clearing and grubbing should not be requireo. Backfill materials, if required, should be planed and compacted according to tine recommendations presented in the structural Fill section of this report. Wet Conditions: Because of the medium dense and elevated silt contents, the existing site soils at shallow depths are moisture -sensitive and prone to disturbance when wet. The contractor should minimize traffic above the prepared subgrade areas to minimize disturbance and softening which would require removal of the unstable soils. During wet conditions, the use of a working surface of quarry spalls or clean sand and gravel may be required to protect the subgrade, especially from vehicular traffic. Frozen Subgrades: If earthwork takes place during freezing conditions, we recommend that all exposed subgrades be allowed to thaw and be recompacted prior to placing subsequent lifts of structural fill. Equipment Building or Cabinets Foundation It is our understanding that the foundation for the proposed equipment building or cabinets will consist of a poured in place concrete slab -on -grade with thickened edges. We anticipate that the pad bearing pressure will be relatively light. I lowever, we recommend that the thickened slab edges be designed as spread footings. The following recommendations and comments are provided for purposes of footing design and construction: Suhgrade Conditions: The proposed equipment pad may be supported by thickened slab edges extended to hcar on the existing site soils encountered at depths below 2 feet at the location of boring B-I, after they have been compacted in place resulting in a firm and unyielding subgrade condition, or upon structural fill placed above similarly prepared native soils. Some overexcavation may be necessary if soft subgrades were to he encountered at the foundation design grade levels. Footings should never he cast atop soft, loose, organic, or frozen soils; nor atop subgrades covered by standing water. A representative from ADaPT should be retained to observe the condition of footing subgrades before concrete is poured to verif'- that they have been adequately prepared.