Laserfiche WebLink
_12_. <br />should have a maximum liquid limit of 30"a. Structural till <br />• placed below spread footings should be compacted to at least <br />100p of the standard Proctor density (AST h1 D698) at a <br />moisture content within 2 percentage points of optimum. Care <br />should be taken not to compact the natural soils dry of <br />optimum moisture as this could increase the swell <br />potential. Structural fill s~.ould extend beyond the edge of <br />the footing equal to at least the depth of the fill belou the <br />footing. The structural fill should be observed and tested <br />by a representative of the geotechnical engineer on a full- <br />time basis. <br />3) Spread footings should have a minimum width of 20 inches for <br />walls and 36 inches for isolat^d column pads. <br />• 4) Footings should be provided ~•:ith adequate soil cover above <br />their bearing elevation for f-ost protection. Placement of <br />foundations at least 36 inches below the exterior grade is <br />typically used in this area. <br />5) Continuous foundation walls should be reinforced top and <br />bottom to span an unsupported length of at least 15 feet. <br />6} A variation of the spread footing foundation is a heavily <br />reinforced mat and box type grade beam foundations. These <br />type foundations are more resistant to differential founda- <br />lion movements than isolated spread footings due to the heavy <br />reinforcement and continuous nature of the Foundation. The <br />designer should evaluate the feasibility of these type <br />foundations which may be used overall or in part of the <br />• structure. <br />Chen&Associates <br />