1001 E MARINE VIEW DR SITE WORK AND UTILITIES 2018-01-01 MF Import

SteBen Jacobson JN 98313 August 17. 1998 Page 9 General Earthwork and Structural Fill Structural fill is defined as any fill placed under a building, behind permanent retaining or foundation walis. or in other areas where the underlying soil needs to support loads. All structural fill should be placed in horizontal lifts with a moisture content at, or near, the optimum moisture content. The optimum moisture content is that moisture content that results in the greatest compacted dry density. The moisture content of fill is very important and must be closely controlled during the filling and compaction process. The allowable thickness of the fill lift will depend on the material type selected. the compaction equipment used, and the number of passes made to compact the lift. The loose lift thickness should not exceed 12 inches. We recommend testing the fiil as it is placed. If the fill is not comoacted to specifications, it can be recompacted before another lift is placed. This eliminates the need to remove the fill to achieve the required compaction. The following table presents recommended relative compactions for structural fill: Location c( Minimum Fill Placement Relative Compaction Beneath footings, slabs 95% or walkways Behind retaining walls 90% 95°/a for upper 12 inches of Beneath pavements subgrade; 90% below that Ievel Whero: Minimum Retative Compaction is the ratio, expressed in percentages, ot tho compacted dry densiry to tho mazimum dry densiry, as determined in aceordanca wilh ASTM Test Designation D 1557-TB(Modified Proetor�. Use of On-Site Soil If grading activities take place during wet weather, or when the silty, on-site soil is wet, site preparation costs may be higher because of delays due to rain and the potential need to import granular fill. The on-site soil is generally silty and therefore moisture-sensitive. Grading operations will be difficult during wet weather, or when the moisture content of this soil exceeds the optimum moisture content. The moisture conten! of the silty, on-site soil must be at, or near, the optimum moisture content, as the soil cannot be consistently compacted to the required density when the mcisture content is significantly greater than optimum. The moisture content of the on-site soil was generally above the estimated optimum moisture content at the time of our explorations. Moisture-sensitive soil may also be susceptible to excessive softening and "pumping" from construction equipment, or even foot tra�c, when the moisture content is greater than the ootimum moisture content. It may be beneficial to protect footing subgrades with a layer of washed crushed rock or a thin layer of lean concrete to limit disturbance from traffic. arnrrcii�m, si�cr,��rs.i�c