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A. Place backfill and fill materials in layers not more than 8 inches in loose depth for material <br /> compacted by heavy compaction equipment, and not more than 4 inches in loose depth for material <br /> compacted by hand-operated tampers. <br /> B. Place backfill and fill materials evenly on all sides of structures to required elevations. Place backfill <br /> and fill uniformty along the full length of each structure. <br /> C. Percentage of Maximum Dry Density Requirements: Compact soil to not less than the following <br /> percentages of maximum dry density according to ASTM D 1557: <br /> 1. Under structures, piers, building slabs, steps, and pavements, compact the top 12 inches <br /> below subgrade and each layer of backfill or fill material at 95 percent maximum dry <br /> density. <br /> 2. Under walkways,compact the top 6 inches below subgrade and each layer of backfill or fill <br /> material at 95 percent maximum dry density. <br /> 3. Under lawn or unpaved areas,compact the top 6 inches below subgrade and each layer of <br /> backfill or fill material at 90 percent maximum dry density. <br /> 3.12 GRADING <br /> A. General: Uniformly grade areas to a smooth surface,free from irregular surface changes. Comply <br /> with compaction requirements and grade to cross sections, lines,and elevations indicated. <br /> � <br /> l. Provide a smooth transition between existing adjacent grades and new grades. <br /> 2. Cut out soft spots, fill low spots, and trim high spots to conform to required surface <br /> tolerances. <br /> B. Site Grading: Slope grades to direct water away from all building structures(See Drawings and 3.10 <br /> A above)to prevent ponding. Finish subgrades to required elevations within the following tolerances: <br /> l. Lawn or Unpaved Areas: Plus or minus 0.10 foot. <br /> 2. Walks: Plus or minus 0.i0 foot. <br /> 3. Pavements: Plus or minus 1/2 inch. <br /> C. Grading Inside Building Lines: Finish subgrade tolerance to 1/2 inch when tested with a 10-ft <br /> straightedge. <br /> 3.13 SUBBASE AND BASE COURSES <br /> A. Under pavements and walks,place subbase course material on prepared subgrades. Place base <br /> course material over subbases to pavements. <br /> 1. Compact subbase and base courses at optimum moisture content to required grades,lines, <br /> cross sections and thickness to not less than 95 percent of ASTM D 4254 relative density. <br /> 2. Shape subbase and base to required crown elevations and cross-slope grades. <br /> 3. When compacted subbase or base course thickness is 6 inches or less,place materials in a <br /> single layer. <br /> 4. When thiclmess of compacted subbase or base course exceeds 6 inches,place materials in <br /> equal layers, with no layer more than 6 inches thick or less than 3 inches thick when <br /> compacted. <br /> Page 5 of 6 <br />