<br />27 <br /> <br />certerra.com 4660 Main Street, Suite 100, Springfield, Oregon 97478 T: 541.393.6340 <br />Gravity). The geotextile fabric should be placed over a smooth subgrade and should be placed with no wrinkles. The <br />fabric should be overlapped a minimum of 18 inches. Construction equipment should not be permitted to travel <br />directly on the geotextile fabric. Water should not be allowed to pond behind curbs and saturate the base course. In <br />down grade areas, base course should extend through the slope to allow any water entering the base course a path <br />to exit. <br /> <br />The base course should consist of well-graded crushed stone. Imported base course materials should be free of <br />organics or other deleterious materials, have a maximum particle size generally less than 2 inches, contain 5 <br />percent soil passing the U.S. #200 sieve, be well graded, and have a liquid limit less than 45 and plasticity index <br />less than 25. When placed, the lift base course thickness should generally not exceed 12 inches prior to <br />compacting. The type of compaction equipment used will ultimately deter mine the maximum lift thickness. In <br />addition, we recommend that the structural fill be placed within +/- 2 percent of the optimum moisture for that <br />material. <br /> <br />Base course materials placed under proposed private roads should be compacted to a minimum of 92 percent <br />of a modified Proctor (ASTM D1557 or AASHTO T180). Base course materials placed under the proposed public <br />road should be compacted to a minimum of 95 percent of a modified Proctor. <br /> <br /> <br />3.7 Recommended Follow-up Engineering Services, Construction Observations and Inspections <br /> <br />3.7.1 Plan Review and Geotechnical Construction Inspection <br /> <br />At the time of this report, the Floral Hill Drive project is in the early planning stages, and as such, some of the <br />future development may require geotechnical engineering recommendations that are different from what is <br />contained herein. It will be important for Certerra to review the project plans and perform construction inspections <br />for the specific buildings and roadways as they are developed. <br /> <br />3.7.2 Supplemental Lot Specific Investigation Reports <br /> <br />The subsurface exploration program for this report was intended to broadly cover the entire project site. It was <br />not practical at the time of this report to perform a test pit at every proposed building or roadway location, <br />however, when the individual building lots are developed, we recommend that Certerra be retained to perform <br />lot specific geotechnical investigation reports that include at least one supplemental test pit for those lots that do <br />not already have a test pit on them. Note that, to save on costs, additional lot-specific test pits could be performed <br />at the same time that excavations for footings or slabs are performed, or while we are already on site performing <br />other observations and testing. <br />