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Inwood 10 LLC <br />Project B14-08413 <br />December 3, 2014 <br />Page 12 <br />On-site soils free of organic soil and debris can be considered for placement up to design subgrade <br />elevations in pavement areas. Note again the clay soils will be more difficult to compact if wet or allowed <br />to become wet, or if spread and compacted over wet surfaces. <br />D.6.b.Subgrade Proofroll <br />Prior to the placement of the aggregate base, we recommend the subgrade soils be proofrolled with a <br />fully loaded tandem-axle truck and the proofroll be observed by a geotechnical engineer. This will assist <br />in identifying soft or weak areas will require additional soil correction work. Areas that display excessive <br />yielding or rutting during the proofroll should be corrected. In areas where subgrade correction is <br />deemed necessary, unsuitable soils should be removed to soils of adequate density or to a maximum <br />depth of 3 feet. Failed areas should be compacted, or if too wet, subcut and replaced with suitable soil or <br />additional aggregate base and compacted as previously specified. <br />D.6.c.R-Value <br />Laboratory tests to determine an R-value for pavement design were not included in the scope of this <br />project. Based on our experience with similar soil conditions, however, it is our opinion an R-value of 30 <br />can be assumed for design purposes. This R-value is based on a pavement section directly supported on a <br />poorly graded sand to silty clayey sand subgrade. If clayey sand or sandy lean clay subgrades are <br />anticipated on final grades, lower R-values in the range of 12 to 20 may be needed and the pavement <br />section may be supported on engineered fill. In that case the R-value will have to be reevaluated based <br />on the engineered fill material. <br />D.6.d.Pavement Sections <br />Based on our experience with typical commercial sites as illustrated on your conceptual design in <br />Section A, we anticipate the parking lots and roadways will likely have a larger volume of automobiles <br />and delivery or garbage trucks than the residential portion of the development. In these areas a light- <br />duty pavement section ranging from 3 to 3 1/2 inches of bituminous pavement over 6 to 9 inches of <br />aggregate base material are anticipated. If any of these proposed buildings or roadways is expecting <br />larger amounts of large truck traffic, thicker sections may be needed. These sections are anticipated to <br />be on the order of 4 to 5 inches of bituminous pavement over 8 to 12 inches of aggregate base material. <br />In areas with high point loads such as truck parking areas or loading docks, concrete pavement should be <br />considered. Wherever concrete pavements will be utilized, the appropriate panel sizing, jointing, <br />doweling and edge reinforcement are critical to the ridged pavement performance.