500 LAUREL DR 2016-01-01 MF Import

Geotechnical Engineering Study 00-2267 Three Story Addition - 500 Laurel Street, Everett January 31, 2001 L Page 16 '" dry weather any organic-free, compactible material meeting the above maximum size criterion is acceptable for this purpose. From our field observations it is our professional opinion that the majority of the in- situ shallow soils (those materials likely to be excavated from the yard area) are in a generally suitable condition for reuse as a structural fill. However, we strongly urge that they be kept within about two points of the rriaterials' Modified Proctor optimum moisture content to avoid the potential reaction likely in "moisture sensitive" soils. Fill Placement and Compaction: Structural fill under floor slabs and footings, in utility trenches, or in driveway or parking area subgrades should be placed in thin horizontal lifts not exceeding ten (10) inches in loose thickness for heavy compactors and four inches for hand held compaction equipment. Each lift should be compacted to a minimum of 95 percent of the maximum Modified Proctor dry density, or to the applicable minimum City standard, whichever is the more conservative. As indicated above, to facilitate the earthwork and compaction process, the earthwork contractor should place and compact fill materials at, or near (typically within about two points), the optimum moisture content. 1'his should help enhance t��e compactibility of the materials and avoid the risks involved with wet, moisture sensitive soils. If fill materials are on the wet side of optimum they will need to be dried to within about two points of the Modified Proctor optimum moisture content. This can be accomplished relatively inexpensively by periodic windrowing and aeration. Native Subgrade Soil Density Testing: It is imporlant that the owner, and his contractor, recognize that in-place density testing of the native subgrade soil is unnecessary and inappropriate. If the native soil is tested it is virtually certain that the results will indicate a"failing" degree of compaction. This does not mean the native soil is unacceptabie for load bearing purposes, only that it is not behaving in the same manner as a compacted structural fill. Instead of performing in-situ density tests in the native soil it is usually preferable to have the geotechnical engineer probe the subgrade with a sma(i diameter steel rod. The magnitude of rod penetration, coupled with the engineers' visual