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5.0 CONSTRUCTION CONSIDERATIONS <br />5.1 Excavation <br />The soil encountered in the borings consisted of poorly graded sand corresponding to the ASTM <br />Classifications SP. The soils identified in the boring will generally be Type C soils under <br />Department of Labor Occupational Safety and Health Administration (OSHA) guidelines. <br />Temporary excavations in Type C soils should be constructed at a minimum of 11/2 foot horizontal <br />to every 1 foot vertical within excavations. Slopes constructed in this manner may still exhibit <br />surface sloughing. If site constraints do not allow the construction of slopes with these <br />dimensions, then temporary shoring may be required. <br />5.2 Observations <br />A geotechnical engineer or qualified engineering technician should observe the excavation <br />subgrade to evaluate if the subgrade soils are similar to those encountered in the borings and <br />adequate to support the proposed construction. <br />5.3 Backfill and Fills <br />Site soils that will be excavated and reused as backfill and fill appear to be below their assumed <br />optimum moisture content. We anticipate it may be necessary to moisture condition (wet) these <br />soils to achieve the recommended compaction. We recommend that fill and backfill be placed in <br />lifts not exceeding 4 to 12 inches, depending on the size of the compactor and materials used. <br />5.4 Testing <br />We recommend density tests of backfill and fills placed for the proposed roadway and utilities. <br />Samples of the proposed materials should be submitted to our laboratory prior to placement for <br />evaluation of their suitability and to determine their optimum moisture content and maximum <br />dry density (Standard Proctor). <br />5.5 Winter Construction <br />If site grading and construction is anticipated to proceed during cold weather, all snow and ice <br />should be removed from cut and fill areas prior to additional grading and placement of fill. No <br />fill should be placed on frozen soil and no frozen soil should be used as fill or backfill. <br />Concrete delivered to the site should meet the temperature requirements of ASTM and/or ACI. <br />Concrete should not be placed on frozen soil. Concrete should be protected from freezing until <br />the necessary strength is obtained. <br />9 <br />