2610 VIEWCREST AVE 2022-04-13 - Laserfiche WebLink

McCann Property Geotechnical Services Report 2610 Viewcrest Avenue,Everett, Washington Based on the current site plan excavation requirements are relatively small. Planned cuts and fills should nearly balance and both import and export of materials from the site is expected to be low. The on-site soils are generally granular in nature with varying amounts of fines. Although no laboratory testing of grain size was performed,visually it is estimated that the upper sands are fine to medium grained and the lower sands are medium to coarse grained. Fines content is estimated to range from 3 to 12 percent in the lower sands. The upper loose sand contained a higher percentage of fines. These soils, where no organics are present, can be used for on-site backfill purposes. Once excavated they should be stockpiled and-protected from rain by covering with plastic sheeting in order to maintain in-situ moisture content. Foundations Based on our field explorations suitable bearing soils will be encountered at a shallow depth and typical spread footing foundations may be used for building support. The upper 2 to 3.5 feet of soil was in a loose condition. However, current excavation plans should remove the majority of these loose sediments. Where any loose sediments remain they must be compacted to a medium dense or better condition prior to concrete placement. Foundations placed on medium dense or better granular soils should be designed for an allowable soil bearing of 2,000 psf. An increase of one-third will be appropriate for short term wind or seismic loading conditions. Lateral resistance will be provided be soil pressure against the footings and foundation walls and/or by friction between building elements and the soil. We recommend a passive resistance value of 200 pcf and a soil friction value of 0.30 for this site. These values are allowable and have a minimum factor of safety of 1.5. All backfill around foundation elements(footings and stem walls) should be compacted to a medium dense or better condition in order to provide suitable lateral passive soil resistance. No footing should be placed on soil that is loose or has been disturbed unless it is suitably recompacted to a firm and unyielding condition. All footing subgrade soils should be approved by a representative of this office prior to concrete placement. Floor Support Recommendations The existing granular soils will provide suitable support for slab-on-grade floors provided that they are re-compacted to a firm, unyielding condition. Compaction should be attained with a hoe-pac, walk behind vibratory compactor or large sled compactor. Small sled compactors used for surficial leveling and compaction are not suitable for this purpose. Suitable compaction should be verified by the geotechnical professional prior to concrete placement. If any unsuitable soils are observed during excavation and/or compaction they should be removed and replaced with appropriate structural fill material. Gary A.Flowers,PLLC. 5205 23'Avenue W Everett,Washington 98203 206-819-4304 3