3003 W CASINO RD BLDG 45-12 2016-10-20

4 1 777X Static Test Building Paine Air Field is located within the eastern end of the Southern Whidbey Island Fault Zone. The Southern Whidbey Island Fault Zone is a northwest-trending fault that is 3 to 4 miles wide and extends more than 40 miles from Whidbey Island to east of the project site. The likelihood of a rupture within the fault zone is low;therefore, surface rupture at the building location is unlikely. The Southern Whidbey Fault produced a large earthquake that left a geologic record approximately 3,000 years ago. Based on this information,we classify the potential for surface rupture as low within the 50-year design life of the structure, but greater than it would be for a site outside a known fault zone. The soils at the project site generally consist of very dense,very silty sand below the groundwater table. Based on the dense nature of the glacially overridden soils,we conclude that the risk of liquefaction and post-liquefaction settlement in a design-level earthquake is very low. Also,the site is relatively flat;therefore,the potential for slope movement is low. Building Code Seismic Response Spectrum Parameters Table 1 provides 2012 International Building Code(IBC)seismic design parameters for the site latitude and longitude.The parameters were obtained from the U.S. Geological Survey(USGS) Seismic Design Maps web application (http://geohazards.usgs.gov/designmaps/us/application.php) accessed on May 13, 2015. Table 1 - 2012 IBC Seismic Design Parameters Parameter Value Latitude 47.9127 Longitude -122.2741 Site Class C Mapped MCER Spectral Response Acceleration at Short Periods,Ss 1.443 g Mapped MCER Spectral Response Acceleration at 1-Second Periods, Si 0.562 g MCE Geometric Mean Peak Ground Acceleration, PGAM 0.614 g Building Foundations The building site is underlain by medium dense sand overlying very dense,silty sand that we interpret as glacial till. The building slab finish floor elevation will be at 565 feet with the foundations bearing 2 to 5 feet lower. Based on our explorations,the glacial till bearing layer is between 0(eastern side of building) and 10(western side of building)feet below the proposed base of footing elevations. These elevations are shown with contours on Figure 2. We understand that the building will be supported on large continuous footings, up to 12 feet in width. Unsuitable foundation materials,such as organic soils, present in the drainage ditch north of the building or the detention ditch to the south,or the highly organic soil encountered in boring HC-9 will require overexcavation and replacement before structural loads may be placed in these areas. MrN 19106-01 ALM May 29,2015 HAWOTOWW--R