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

2 I 777X Static Test Building The proposed testing facility will require a reaction loading frame that will be required to resist uplift point loads between 350 and 780 kips. These uplift loads will be resisted by micropile groups installed into the underlying bearing layer at the site. Proposed site grades are 5 to 12 feet below the current grade over most of the site, as well as the adjacent roadways to the east and south. We understand that the site grades will be achieved by mass excavation and construction of retaining walls along these roadways. Cantilevered soldier pile walls are proposed. SITE GEOLOGY The geology of the site is identified from the Washington State Department of Natural Resources Geologic Map 20(Smith 1976).The geologic mapping shows that the project site is underlain by Pleistocene continental till, mapped as Vashon till. It is described as poorly sorted, nonstratified lodgment till deposited as a ground moraine. These deposits consist largely of a mixture of clay,silt, sand,gravel, and cobbles with occasional large boulders. It is described as extremely compact, often capable of standing near vertical, and generally lacking surficial cracks or joints. Some areas of Vashon till are covered by a thin veneer of loosely consolidated, non-sorted ablation till and thin outwash. SUBSURFACE CONDITIONS The conclusions and recommendations in this report are based on subsurface conditions interpreted from our subsurface explorations and past geotechnical information collected at the site and provided by Boeing. Hart Crowser drilled ten borings, designated HC-1 through HC-10,to depths between 30 and 120 feet bgs. Exploration locations are shown on Figure 2. A description of our field exploration program and methods, as well as the exploration logs are included in Appendix A. A laboratory testing program was completed on samples collected during the investigation. Laboratory testing results are presented in Appendix B. Boring logs from the previous work at the site are included in Appendix C. The subsurface information used for this study represents conditions at discrete locations across the project site, and actual conditions in other areas could vary. Furthermore,the nature and extent of any variations may not become evident until additional explorations are performed or until construction begins. If significant variations are observed at that time,we may need to modify our conclusions and recommendations accordingly to reflect actual site conditions. Soil Conditions The exploration logs identify the following general soil units. ■ Asphalt. The asphalt concrete pavement in the existing parking lot was approximately 2 inches thick at the boring locations. MrW 19106-01 /f May 29,2015 HMTOZOwSM