500 LAUREL DR 2016-01-01 MF Import

Geotechnical Engineering Study Page 17 00-2267 Three Story Addition - 500 Laurel Street, Everett January 31, 2001 evaluation of the exposed subgrade soil and his experience and engineering judgement, is a reasonably accur�te determina+.or of the subgrade soils' competency. Impacts on Buried Structures: It is also important that no large or heavy compaction equipment be used within about five feet of either a retaining or basement wall, or any manhole or catch basin structure. If large equipment is used in these areas there is a risk that excessive lateral pressures could be developed and applied to the structure by the equipment. This could lead to damage to, if not failure of, the structures. We recommend that a small walk-behind roller be used in these areas, and that the fill be placed in loose lifts of no more than four inches in thickness. Larger compaction equipment may be used beyond that point. Fill Source Evaluation: In the event that fill materials are to be imported to the site, or if on-site soils are to be reused as a fill, it will be necessary to evaluate the potential till source before any material is removed and used. We recommend that the geotechnical engineer be required tu visit each and every potential fill source to obtain randomly selected representative samples of the potential sourre materials. These samples will then be submitted for laboratory testing to determine �he material's maximum dry density and optimum moisture content. The sou,ce materials should be tested in general accordance with the Modified Proctor test methodology. The Maximum density and the optimum moisture ,ontent are then used in the field as a gauge to determine the approximate degree of fill compaction being achieved by the earthwork contractor. Depending on the general composition of the source materials, a gradational analysis may be appropriate to determine both the gravel and fines content. Wet'Neather Construction: As indicated earlier, most of the in-place soils are, because of the silt and clay sized fines content, considered to be "moisture sensitive" in nature. This means that they should be expected to be difficult to work or compact when wet, and that they should be expected to deteriorate rapidly under even light pedestrian construction activity. � To help reduce the potential negative impacts wet weather might have on these soils we recommend that earthwork be performed in relatively small areas ta