31. Proof-roll the base rock prior to paving using a loaded 103 yd. dump <br />truck. Overexcavate and replace any areas observed to be pumping. <br />Do not allow loaded trucks or heavy construction equipment on the <br />finished base rock prior to paving. <br />32. For flexible pavements, use a minimum AC thickness of 3 inches. In <br />parking stalls the minimum AC thickness may be reduced to 2.5 inches. <br />Compact the AC to a minimum of 91 % relative compaction according to <br />the theoretical maximum density calculated from the Rice specific <br />gravity. <br />33. For areas of rigid pavement, provide a minimum PCC thickness of <br />6 inches. Specify a minimum compressive strength of 4,000 psi and a <br />minimum flexural strength of 600 psi for the concrete. <br />Dry Weather Construction <br />In the event the earthwork is delayed into dry weather, a number of items can be <br />modified. Among them are: <br />34. During dry weather, prepare, compact and test the subgrade as <br />specified above (Item 6). Maintain the moisture in the subgrade to <br />prevent excessive drying and cracking. <br />35. The use of Fine-grained Site Fill is permitted during dry weather. <br />Fine-grained Site Fill should consist of approved soil that is free of <br />organics, construction debris or soil with a plasticity index (PI) greater <br />than 20. This material may only be used for earthwork completed <br />during dry weather. Fine-grained Site Fill may be generated from fill. <br />already on-site or may be imported from approved borrow sources. <br />36. Reduce the base rock thickness for the building pad and flexible (AC) <br />pavement to 12 inches. Reduce the base rock thickness beneath rigid <br />(PCC) pavements to 6 inches. <br />DESIGN REVIEW/CONSTRUCTION OBSERVATION/TESTING <br />We should be provided the opportunity to review all drawings and specifications <br />that pertain to site preparation, foundation construction and pavements.. Site <br />preparation will require field confirmation of foundation soils and pavement <br />subgrade conditions, as well as approval of proposed site fill material. Mitigation <br />of any subgrade pumping will also require engineering review and judgment. That <br />judgment should be provided by one of our representatives. Frequent field density <br />tests should be run on all engineered fill, subgrade and base rock. We recommend <br />that we be retained to provide the necessary construction observation. <br />Oakleigh Meadows Cohousing <br />Geotechnical Investigation <br />Eugene, Oregon <br />12. <br />February 12, 2013 <br />Project 2131004 1457 <br />Willard C. Dixon Architect, LLC <br />