9001 AIRPORT RD SNO ISLE SKILL CTR EXPANSION 2009 Geotech Report 2018-01-02 MF Import

I Swbsurfate Exploration, Geobgic Hazard, and Sho-ltle Skips Ceruer Addition Preliminary Geottchnica/Engineering Repon Everea Washington Prelimiwry Design Recommendations t 12.0 FLOOR SUPPORT CONSIDERATIONS I Slab-on-grade floors may be used over structural fill or the medium dense to very dense lodgement till. For design purposes, a vertical modulus of subgrade reaction of 50 pounds per i cubic inch (pci) can be used for floor slabs constructed over properly placed and comQacted l structura! fill. ISlab-on-grade floors should not be placed on ezisting fill soils. Where moisture migratioa � throug6 slabs is to be controlled, the floor should be cast atop a minimum of 4 inches of washed rock or pea gravel to act as a capillary break. The floor should also be protected from � dampness by an impervious moisture banier at least 10 mils in thickness. I 13.0 PAVEMENT DESIGN RECOMMENDATIONS We anticipate that asphalt paving will be used for the new drive and pazking azeas. Asphalt I pavement design is a compromise between initial cost and expected design life. In order to � provide a 20-year design life with normal maintenance, we recommend a pavement section I consisting of 2'/z inches of asphalt surfacing above 6 inches of crushed surfacing base course, per WSDOT Standazd Specification 9-03.9[3], above a granular subgrade compacted to at least 95 percent of the modified Proctor maximum dry densiry, as determined by ASTM:D 1557. l Areas that will be used for delivery wcks, buses, gazbage trucks, or other heavy vehicles should be designed using a paving section consisting of 4 inches of Class "B" asphalt above 6 inches of compacted crushed surfacing base wurse over a 95 percent compacted granular Isubgrade. We anticipate that Portland cement concrete (PCC) will be used for walkways and courtyazds. Wc :xommend a concrete sidewalk and courtyazd section consisting of 4 inches of PCC � surfacing above a minimum of 4 inches of crushed surfacing top course, per WSDOT Standazd Specification 9-03.9(3], alwve a subgrade compacted to at least 95 percent of the modified i Proctor maximum dry density, as determined by ASTM:� 1557. Areas that will be crossed by delivery trucks, buses, gazbage uucks, or other heary ��ehicles should be designed using a I section consisting of at least 6 inches of PCC above a minunum of 8 inches of compacted crushed surfacing top course above a subgrade compacted to at least 95 percent. I After the azeas to be pave�l aze suipped and/or excavated to pavement subgrade eleaatian, t6e exposed ground should be compacted to at least 95 percent of ASTM:D 1557, or to a firm a� unyielding condition, as determined by the geotechnicai engineer or his representative. We � recommend proof-rolling pavement subgrades that will underlie vehicle traffic with a baded dump truck to identify any soft or yielding azeas. If required, structural fill may then be placed to achieve desired subbase grades. Upon completion of the compaction and suuctural � fill placement, the pavement section for the design level of services can be consavcted. I lune 1l, 1008 ASSOC/AlEI)EAR7N SCIENCES,/NC. i PagC 16 �q) EG/Id-E[Q901/3A5-ProjtarlZOp602131fE�wP v�