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Kraus-Anderson Realty Company Project BL-11-01014 March 18, 2011 Page 14 D.6.d. Materials and Compaction We recommend that bituminous mixtures be compacted to a minimum of 95 percent of their Marshall densities. We recommend that aggregate base course meet the requirements of Minnesota Department of Transportation (Mn/DOT)Specification 3138 for Class 5 aggregate.We recommend the crushed aggregate base course and engineered fill placed within 3 feet of pavement subgrades be compacted to a minimum of 100 percent of the material's maximum dry density(standard Proctor method). Backfill and fill placed more than 3 feet below pavement subgrade elevations should be compacted to at least 95 percent. D.7. Utilities Based on the borings, much of the area where new utilities will be installed is underlain by existing fill soils overlying swamp deposits. It appears that some compression of the swamp deposits in this area has occurred over time due to the weight of the fill soils. However,these soils may still be compressing somewhat and the placement of additional fill soils in excess of 3 to 4 feet in these areas could result in further compression leading to utility settlement.We recommend that utilities be designed to allow some movement. We understand the 10-inch water main and 4-inch sanitary sewer lines will be directionally drilled.This method of installation uses fused,flexible piping that can tolerate some settlement. We note that with leaving the swamp deposits in place under utility lines,the possibility still exists of excessive settlement to occur.The owner must be willing to accept this risk, if not; additional measures will need to be taken to remediate the swamp deposits.These measures would include the removal of all swamp deposits under utilities and replacement with new engineered fill. For open cut utility construction, if unfavorable conditions such as soft clay or organic soils are encountered at invert grades,the unsuitable soils may require some additional sub cutting and replacement with sand or crushed rock to prepare a proper subgrade for pipe support. Utilities should not be placed within the 1:1 over sizing of foundations. If it is necessary to place utilities within the over sizing of the footings, we should review the documents prior to construction as it may be necessary to backfill with lean concrete or lower the footing elevations near the utility trenches. If water is encountered during utility excavations, dewatering should be performed. BRAUN INTERTEC