3301 SEAWAY BLVD Geotech Report 2022-10-25

Geotechnical Report Seaway Center 36th Avenue West and Seaway Boulevard Everett, Washington 1.0 PROJECT DESCRIPTION The project consists of developing the approximately 16-acre site with 2 industrial buildings, a stormwater detention pond, retaining walls, and associated site infrastructure. Based on the preliminary grading, storm drainage, and utility plan prepared by Barghausen Consulting Engineers dated December 11, 2014, one approximately 61,000 square-foot building will be located on the western side of the site and the second approximately 108,000 square-foot building will be located in the approximate center of the site. In order to accommodate the topography, the buildings will be terraced with the finished floor grade of the western building at elevation 572 feet and the central building at Elevation 534 feet. Grading to establish building and roadway elevations will involve cuts approaching 26 feet in the west- southwestern site portion of the site with fills of up to 14 feet in the north and eastern portions of the site. The development will be accessed from both the west and south off of 36th Avenue West and Seaway Boulevard respectively. Grade transitions throughout the site will be accommodated with site retaining walls and 2:1 (Horizontal:Vertical)sloped embankments. Stormwater will be collected and routed to a detention pond located on the east side of the site. The pond will be formed by a combination of excavation below-grade along the north, south,and west perimeters and construction of a fill containment berm along the east perimeter. The west perimeter will be partially supported by a retaining wall. The excavation required to achieve the floor elevation of 510 will extend up to 24 feet below current site grades. The fill depth required to achieve the berm crest elevation of 522.5 will range from 0 to 14.5 feet. The pond berm width is 6 feet,with interior pond slopes graded at 3:1 and exterior pond slopes graded at 2:1. We anticipate that the buildings will be constructed using precast concrete tilt-up wall panels with interior columns supporting the roof framing. Structural loading is expected to be light to moderate, with isolated columns carrying loads of 50 to 200 kips, and bearing walls carrying 4 to 8 kips per foot. The building floors will be constructed at grade with dock high loading on the east side of the western building and both the north and south sides of the central building. The recommendations contained in the following sections of this report are based on our understanding of the above design features. If actual features vary or changes are made,we should review them in order to modify our recommendations, as required. We should review final design drawings and specifications to verify that our recommendations have been properly interpreted and incorporated into project design.