1610 SE EVERETT MALL WAY Geotech Report 2022-10-25

Subsurface Exploration, Geologic Hazard, and Krebs Property Preliminary Geotechnical Engineering Report Everett, Washington Preliminary Design Recommendations 11.3 Passive Resistance and Friction Factor Lateral loads can be resisted by friction between the foundation and the natural, medium dense to dense glacial sediments or supporting structural fill soils, or by passive earth pressure acting on the buried portions of the foundations. The foundations must be backfilled with compacted structural fill to achieve the passive resistance provided below. We recommend the following design parameters. • Passive equivalent fluid = 250 pcf • Coefficient of friction = 0.30 The above values are allowable. 12.0 FLOOR SUPPORT Slab-on-grade floors may be constructed either directly on the medium dense to very dense natural sediments, or on structural fill placed over these materials. Areas of the slab subgrade that are disturbed (loosened) during construction should be recompacted to an unyielding condition prior to placing the pea gravel, as described below. If moisture intrusion through slab-on-grade floors is to be limited, the floors should be constructed atop a capillary break consisting of a minimum thickness of 4 inches of washed pea gravel. The pea gravel should be overlain by a 10-mil (minimum thickness) plastic vapor retarder. 13.0 DRAINAGE CONSIDERATIONS All retaining and perimeter footing walls should be provided with a drain at the base of the footing elevation. Drains should consist of rigid, perforated, polyvinyl chloride (PVC) pipe surrounded by washed pea gravel. The level of the perforations in the pipe should be set at or slightly below the bottom of the footing, and the drains should be constructed with sufficient gradient to allow gravity discharge away from the buildings. In addition, all retaining walls should be lined with a minimum, 12-inch-thick, washed gravel blanket that extends to within 1 foot of the surface and is continuous with the footing drain. Roof and surface runoff should not discharge into the footing drain system, but should be handled by a separate, rigid, tightline drain. In planning, exterior grades adjacent to walls should be sloped downward away from the structures to achieve surface drainage. February 13, 2007 ASSOCIATED EARTH SCIENCES, INC. TJP/!d-KE070023A1-Projects120070023IKEIWP Page 13