3313 OAKES AVE 2020-07-14 - Laserfiche WebLink

GeoTest Services,Inc. December 9,2016 3313 Oakes Avenue,Everett,WA Job No.16-0659 Fill and Compaction Structural fill used to obtain final elevations for footings and soil-supported floor slabs must be properly placed and compacted. In general, any suitable, non-organic, predominantly granular soil may be used for fill material provided the material is properly moisture conditioned prior to placement and compaction, and the specified degree of compaction is obtained. Material containing topsoil, wood, trash, organic material, or other debris will not be suitable for reuse as structural fill and should be properly disposed offsite or placed in nonstructural areas. Soils containing more than approximately 5 percent fines are considered moisture- sensitive, and are very difficult to compact to a firm and unyielding condition when over the optimum moisture content by more than approximately 2 percent. The optimum moisture content is that moisture content which allows the greatest dry density to be achieved at a given level of compactive effort. Reuse of Onsite Soil Native soil consists of predominantly gravelly silty sand that was interpreted to be representative of till. Till is suitable for re-use as structural fill when placed at or near optimum moisture contents as determined by ASTM D1557 and if allowed for in the project plans and specifications. The till contains high percentages of fines and should be considered moisture sensitive. This soil may be challenging to compact to the requirements of structural fill if the moisture content is more than a few percentage points above optimum. Where possible, we recommend that the re-use of the native till soils as structural fill be performed during the dry season, or during an extended period of dry weather. The contractor and owner should be prepared to manage over-optimum moisture content soils and restrict the use of these materials. Moisture conditioning can be difficult during the wet season, or during extended periods of heavy precipitation. If the native till soils will be considered for use as structural fill in wet weather conditions, these soils should be stockpiled separately and covered with plastic until they are ready for use as structural fill. Imported Structural Fill We recommend that imported structural fill consist of clean, well-graded sandy gravel, gravelly sand, or other approved naturally occurring granular material (pit run) or a well- graded crushed rock. We recommend structural fill for dry weather construction meet WSDOT Standard Specification 9-03.14(2) for "Select Borrow" with the added requirement that 100 percent pass a 4-inch-square sieve. Soil containing more than about 5 percent fines (that portion passing the U.S. No. 200 sieve) cannot consistently be compacted to a dense, non-yielding condition when the water content is greater than optimum. Accordingly, we recommend that imported structural fill for wet weather construction meet WSDOT Standard Specification 9-03.14(1) for "Gravel Borrow" with the added requirement that no more that 5 percent pass the U.S. No. 200 sieve. Due to wet weather or wet site conditions, soil moisture contents could be high enough that it may be very difficult to compact even "clean" imported select granular fill to a firm and unyielding condition. Soils with over-optimum moisture contents should be either scarified and dried back to more suitable moisture contents during periods of dry Page 6 of 17