Laserfiche WebLink
iW"Al, <br />•E ENGINEERING <br />Minimum <br />Fill Application <br />Compaction <br />Footing subgrade and bearing pad <br />95 percent <br />Footing and stemwall backfill <br />90 percent <br />Slab -on -grade floor subgrade <br />95 percent <br />Concrete sidewalk subgrade <br />90 percent <br />Utility trench backfill (below 4 feet) <br />90 percent <br />Utility trench backfill (above 4 feet) <br />95 percent <br />Utility trench backfill (under building <br />95 percent <br />footings or structures) <br />Sub¢rade Verification and Compaction Testing <br />Regardless of material or location, all structural fill should be placed over firm, unyielding subgrades <br />prepared in accordance with the Site Preparation section of this report. The condition of all subgrades <br />should be verified by a MPE representative before filling or construction begins. In addition, fill soil <br />compaction should be verified by means of in -place density tests performed during fill placement so <br />adequacy of the soil compaction efforts may be evaluated as earthwork progresses. <br />Soil Moisture Considerations <br />The suitability of soils used for structural fill depends primarily on their grain -size distribution and <br />moisture content when they are placed. As the "fines" content (the soil fraction passing the U.S. No. 200 <br />Sieve) increases, soils become more sensitive to small changes in moisture content. Soils containing <br />more than about 5 percent fines (by weight) cannot be consistently compacted to a firm, unyielding <br />condition when the moisture content is more than 2 percentage points above or below optimum. For fill <br />placement during wet -weather site work, we recommend using "clean" fill, which refers to soils that <br />have a fines content of 5 percent or less (by weight) based on the soil fraction passing the U.S. No.4 <br />Sieve. <br />OF Strength Considerations <br />Controlled Density Fill (CDF) is normally specified in terms of its compressive strength, which typically <br />ranges from 50 to 200 pounds per square inch (psi). CDF having a strength of 50 psi (7,200 psf) provides <br />adequate support for most structural applications and can be readily excavated with hand shovels. A <br />strength of 100 psi (14,400 psi) provides additional support for special applications but greatly increases <br />MP ENGINEERING, PLLC MPGEOTECH.COM <br />