|
i
<br /> Providence Family Services Center 9-9/M-12723-0
<br /> ( Augus!25. 1999 Pape 12
<br /> Ifindings do not eliminate the possibiliry that cc+ntaminants are present, espeaally
<br /> considering previous site utilization. As such, we recommend that AGRA be
<br /> I retained as an on-call environmental consultant during earthwork phases of the
<br /> construction project.
<br /> The following text sections of this report present our specific geotechnicai conclusions and
<br /> I' recommendations conceming site preparation, spread footings, pile foundations, slab-on-grade
<br /> floors, drainage systems, backfilled walis, asphaltic pavements, drive slabs, and structural fill.
<br /> WSDOT Standard Specifications and Standard Plans cited herein refer to WSDOT publications
<br /> M41-10, 1996 Standard Specifications forRoad,Bridge,and Municipal Conshuction,and M21-01,
<br /> Standard Plans for Road, 9ridge, and Municipal Construction, respectively.
<br /> 6_1 Site Preoaration
<br /> Preparation ofthe project site should involve demolition,temporary drainage,stripping ofold fill and
<br /> i topsoil horizons, cutting, filling, excavations, dewatering, and subgrade compaction. The
<br /> paragraphs below discuss our geotechnical comments and recommendations conceming site
<br /> I preparation.
<br /> Demolition: The first step in site preparation will likely consist of demolishing all existing structures.
<br /> � Any associated underground structural elements or utilities, such as old footings, stemwalls, and
<br /> drainpipes, should be exhumed as part of this demolition operation.
<br /> I Temoorary Drainaae: We recommend intercepting and diverting any potential sources of suriace
<br /> or near-surtace water within the construction zones before stripping begins. Because the selection
<br /> of an appropriate drainage systern will depend on the water quantity, season,weather conditions,
<br /> construction sequence,and con!ractor's methods,final decisions regarding drainage systems are
<br /> best made in the field at the time of construction. Nonetheless, we anticipate that curbs, b�rms,
<br /> or ditches placed around the work areas will adequately intercept surface water runoff.
<br /> Clearina and Striooina: After surface and near-surface water sources have been controlled, the
<br /> construction areas should be cleared and stripped of all trees,bushes,sod,topsoil,debris,asphalt,
<br /> concrete and fill. In existing pavement areas, a stripping depth of about 2 inches will be needed
<br /> to remove asphaltic pavements, and in existing landscaped areas, we estimate that an average
<br /> stripping depth of about 9 inches will be required to remove organic soils. It should be realized that
<br /> if the stripping operation proceeds during wet weather, a generally greater stripping depth might
<br /> � be necessary to remove disturbed moisture-sensitive soils; therefore, stripping is best pertormed
<br /> during a period of dry weather.
<br /> I
<br /> Surface Rearadina: We anticip�'te that grading plans will call for cutting as deep as about 4 feet
<br /> in the topographically high areas of the site, and filling as high as about 3 fe2t in the low areas, to
<br /> i create a level building pad and parking lot subgrade. Based on our explorations,we anticipate that
<br /> � the cuts will encounter loose to medium-dense, silty sands. These soils can likely be cut with
<br /> IS:WOHOPFOC�99Prolect��50��4�110001',12i.:ROEmsm!ProrOenceHosp�RplxyE I IC `
<br /> \J
<br /> I
<br />
|