313 76TH ST SE WESTERN WIRELESS CORPORATION Geotech Report 2018-01-02 MF Import

ADaPT Engineering, Inc. Western Wireless Corporation ADaf T Job No, WA98-993 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: Clearink and Grubbint: 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. Backfill materials, where required, should be placed and compacted according to the recommendations presented in the Structural fill section of this report. Wet Conditions: Because of their loose to medium dense condition, and the significant clay content of the near surface soils, 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 dishubancc 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 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. Ilowever, 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: Subt±radc Conditions: the proposed equipment pad may be supported by thickened slab edges cxicnded to bear on the existing site soils encountered at depths below 1.5 feet at the location of boring B-I, after they have been compacted in place resulting in a fpm and unyielding subgrade condition, or upon structural full placed above similarly prepared soils. We anticipate the subsoil encountered at the proposed foundation grade will likely consist of loose to medium dense clayey sand fill. Depending on the time of year that construction proceeds, it may be possible to compact those soils in place. However, the clayey subsoils have a high fines content, and may be above the moisture content to allow compaction to be achieved. Sonic ovcrcxcavation may be necessary if excessively soft or wet subgrade conditions were to be encountered at tI,e foundation design grade levels. In consideration of the light loads imposed