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� . <br /> � Mr. Charles Thompson <br /> � ' Project BL-04-05907 <br /> � October 27,2004 <br /> ■ Page 11 <br /> � <br /> , <br /> To reduce the amount of long-term sagging, all attempts should be made to leave existing grades at or <br /> � below the current grades. By not raising grades in this area,the underlying organic soils would not be <br /> ■ subjected to additional loadings and consolidation in excess of what they have already experienced. <br /> After site stripping, the pavement subgrade should then be brought back to grade with engineered fill. <br /> � Where�fill is required, we recommend that it consist of mineral soil. The fill should be placed at no more <br /> � than 1 percent over optimum moisture and compacted to at least 100 percent of its standard Proctor dry <br /> density. For soils more then 3 feet below final grades, 95 percent compaction should be sufficient with a <br /> � moisture content within 3 percentage points of optimum. <br /> � <br /> The finished subgrade should be proofrolled with a loaded tandem to determine if additional subgrade <br /> a � correction will be required. Based on the soils encountered we anticipate of the soils will be directly <br /> � suitable for pavement support following subgrade preparation. However, we anticipate limited areas will <br /> , require deeper subgrade correction. In areas where subgrade correction is deemed necessary,poor soils <br /> should be removed to expose soils of adequate density or to a maximum depth of 3 feet. The subgrade <br /> � should be brought back to grade with engineered fill consisting of a mineral soil. <br /> � C.lO.b. Anticipated Subgrade. After the preparation,we anticipate the subgrade will be compacted <br /> , alluvial sandy or clay soil or engineered fill. Laboratory tests to determine the R-values of these soils <br /> ■ were not included in our scope of services. We assumed a value of 10 for our design. <br /> � C.lO.c. Design Sections. For the above subgrade and the assumed light traffic (consisting of automobile <br /> . and light trucks),we recommend a minimum of 3 inches of bituminous surface over 8 inches of crushed <br /> gravel base. �In multiple_use.high_traffic areas,_we recommend;a minimum of 4 inches of bitiiminous �� <br /> . ----- ______ , _ - — <br /> surface over_10_inches of crushed avel base <br /> - ——gT--- _ <br /> • If significant truck traffic is expected(over four semis per day),we should review and revise the <br /> , pavement section. Also,additional analysis and design can be performed if specific traffic.counts <br /> ■ (estimates) are made available and the subgrade soil is defined. <br /> � <br /> � <br /> � <br /> � <br /> a <br /> ■ <br /> ■ <br />