902 PINE ST NORTH SOUND BEHAVIORAL HEALTH TREATMENT CENTER 2025-11-04

GeoTest Services,Inc. November 16,2018 North Puget Sound Behavioral Health—Treatment Center Addition Job No. 18-0770 Fill and Compaction I Structural fill used to obtain final elevations for footings, soil-supported floor slabs or pavements 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. Excavated site material containing topsoil, landscape bark, wood, I trash, organic material, or construction debris will not be suitable for reuse as structural fill and should be properly disposed offsite or placed in nonstructural areas. Reuse of Onsite Soil I Non-organic portions of native glacial till soil (gravelly sand) encountered across the site could be used be used in structural fill applications under pavements and walkways provided it is moisture conditioned,suitably compacted, and if allowed for use in the project plans and specifications. GTS recommends that if native soil is to be considered for reuse under the building foundations as structural fill, that a comprehensive series of laboratory and field tests be performed to verify suitability of material, and that optimal moisture conditions and compaction requirements have been attained. Native soils can be moisture sensitive, especially if utilized during the wet season. Therefore, we anticipate a moisture conditioning program to lower the in-place moisture to within 2 percent of the optimum moisture content, as determined by ASTM D 1557 be I considered if native soils are to be utilized as structural fill. 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 which allows the greatest dry density to be achieved at a given level of compactive effort. Clayey fill soils, such as those found within the upper 5 feet of the project site at B-4 have a high fines content and are not suitable for re-use as structural fill at the project site. We recommend cohesive soils such as those found at B-4 be utilized only for non-structural areas or be properly removed and disposed of offsite. 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 Washington State Department of Transportation (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 than 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 Page 6 of 17