4027 4TH ST SE WWTP STAIR LANDING 2021-12-20

NC.iA Main Office 17311 — 135" Ave NE, A-500 Woodinville, WA 98072 (425) 486-1669 • FAX (425) 481-2510 July 30, 2014 Chevy Chase CG Engineering 250 — 4th Avenue South, Suite 200 Edmonds, Washington 98020 NELSON GECTECHNICAL ASSOCIATES, INC. GEOTECHNICAL ENGINEERS & GEOLOGISTS Geotechnical Engineering Letter Everett Waste Water Pollution Control Facility Everett, Washington NGA File No. 900014 Dear Mr. Chase: Engineering -Geology Branch 5526 industry Lane, #2 East Wenatchee, WA 98802 (509) 665-7696 • FAX (509) 665-7692 This letter documents our opinions and design recommendations regarding the stabilization of two existing stair cases at the Everett Waste Water Pollution Facility located at 4027 — 4" Street on Smith Island in Everett, Washington. INTRODUCTION We have been requested to provide a geotechnical engineering letter regarding the underpinning and stabilization of two staircases that have experienced settlement. The staircases are located on the northeastern and the southeastern corners of the building. The plans indicate that the landing for the southeastern staircase will receive six 2-inch pin piles, and the landing for the northeastern staircase will also receive six pin piles. We were provided with the following documents: • Sheets S-2 "Foundation Plan" and Sheet A-1 "Paving Plan" of the plans titled "City of Everett — Water Pollution Control Facility — Maintenance Facility," prepared by CG engineering, dated July 3, 3014.