3500 TERMINAL AVE Geotech Report 2022-10-25

2 I Port of Everett—South Terminal Wharf& Electrical Upgrades—Phase 2 PROJECT UNDERSTANDING The project site is located at the south end of the Port of Everett facility,which sits on the eastern shore of Port Gardner Bay in Everett,Washington (Figure 1).The site is currently occupied by a pile-supported wharf structure and paved shipping container storage area.The paved upland area of the site is generally level,with a surface elevation of approximately+18 feet mean lower low water(MLLW). Based on the available bathymetric data,directly below the deck the gravel construction dike slopes toward the waterfront at a slope angle varying between approximately 2.3 to 1 and 2.7 to 1. Beyond the extent of the current wharf structure,the ground surface slopes down from an elevation of about-36 feet towards the bottom of Port Gardner Bay at an approximately 7.5 to 1 slope. The current South Terminal wharf was constructed in the late 1970s for Weyerhaeuser Company.The land at the site was reclaimed by constructing an approximately 50-foot-high gravel containment dike.The dike extends longitudinally along the site,with the crest situated about halfway between the existing upland bulkhead and the toe of the natural slope(Figure 2).The area upland of the construction dike was backfilled with dredged material.The current wharf structure is supported by 18-inch and 24-inch octagonal concrete piles installed in the late 1970's,with a portion of it upgraded in 2015 with new 18-inch and 24-inch steel piles between the existing pile bents. Based on our understanding,the proposed upgrade to the South Terminal involves increasing the live load capacity of the deck to 1,000 psf, installing a 100- foot gauge crane rail system,and repairing the select wharf pile caps. SUBSURFACE CONDITIONS Subsurface Explorations Subsurface exploration locations are shown on Figure 2,and generalized subsurface cross sections A-A', B- B',C-C',and D-D'are shown on Figures 3,4,5,and 6, respectively. Our understanding of the subsurface conditions is based on current and historical explorations at the site, and on laboratory analysis of samples from the borings.We completed one seismic cone penetration test (SCPTu)to a depth of approximately 70 feet below ground surface(bgs)on August 15,2016.A second SCPTu sounding was completed at approximately the same location to obtain the shear wave measurements. Between August 2016 and February 2017,we completed six borings, HC-1 through HC-6, to depths of between approximately 60 and 95 feet bgs.Global Geophysics conducted refraction microtremor(ReMi)and multichannel analysis of surface wave(MASW)surveys on August 27, 2016,and provided a shear wave(S-wave)velocity profile.The logs of these explorations are in Appendix A, and the laboratory test results are in Appendix B. We also reviewed recent logs of boring explorations and laboratory tests by Shannon and Wilson, Inc. (2014),as well as the historical boring records from the original as-built drawings for the Weyerhaeuser Mill(1978). Relevant historical exploration locations are shown on Figure 2,and the historical boring logs and laboratory results are in Appendix C. 19232-01 December 6,2017 Si H/V?TO?OVSCR