3003 W CASINO RD BLDG 45-06 Geotech Report 2025-03-03

Geotechnical Engineering Report Proposed Flight Line Steam Line Project lierracon ' Boeing Everett Facility • Everett, Washington January 17, 2012 • Terracon Project No.: 81115085 1 4.3.5 IBC Seismic Design Parameters Code Used Site Classification ' 2009 International Building Code(IBC) C 1 SS Spectral Acceleration for a Short Period 2 1.269 g Si Spectral Acceleration for a 1-Second Period 2 0.452 g 1. In general accordance with the 2009 International Building Code, Table 1613.5.2. The 2009 International Building Code requires a site soil profile determination extending a depth of 100 feet for seismic site classification. The current scope requested does not include the required 100 foot soil profile determination. Borings for the utilidor extended to a maximum depth of approximately 19 ' feet and this seismic site class definition considers that dense to hard glacially consolidated deposits exist below the maximum depth of the subsurface exploration as indicated on the above-reference geologic map. 2. Based on USGS National Seismic Hazard Mapping Project 2009 spectral ordinates (5 percent damping) for Site Class B at building periods of 0.2 and 1.0 seconds for ground motions at the project site with a 2 percent probability of exceedance in 50 years (2,500-year return period). The ' maximum considered earthquake spectral response for short periods, SMS, and 1-second period, SM,, adjusted for Site Class C effects should be determined per Section 1613.5.3 of the 2006 IBC Manual. 4.4 Foundations We understand that the utilidor may use a combination of shallow spread foundations for cast- Iin-place components and mat foundations for precast components. Based on our analyses, conventional spread footings and mat foundations will provide adequate support for the proposed utilidor provided that foundation subgrades are properly prepared. Foundation support for the proposed structure may be obtained from the dense to very dense glacial till soils. We recommend that the entire utilidor foundation system be underlain by at least 6 inches of compacted engineered fill meeting the requirements of Section 9-03.17, Foundation Material Class A, as presented in the WSDOT Standard Specifications for Road, Bridge, and Municipal Construction. The foundation material should be placed directly on dense to very dense glacial till soils. The purpose of the foundation material is to provide 1) protection for the moisture sensitive glacial till subgrade during construction, 2) a leveling surface for ' precast utilidor components, and 3) more uniform support conditions between precast and cast- in-place components. The foundation material should be compacted to a firm and non-yielding condition and to at least 95 percent of the modified Proctor maximum dry density as determined by the ASTM:D-1557 test procedure. Design recommendations for shallow and mat foundation elements are presented in the following sections. Responsive ■ Resourceful ■ Reliable 13