Preliminary Geotechnical Engineering Report <br />Project No. 18-4986, 177 Day Island Road, Eugene, Oregon <br />NO " <br />Table 2 - Flexible Pavement Section Design Input Factors for Private Drive/Parking Lot <br />Input Parameter <br />Design Value <br />18-kip ESAL Initial Performance Period (20 Years) <br />26,624 <br />Initial Serviceability <br />4.2 <br />Terminal Serviceability <br />2.5 <br />Reliability Level <br />85 Percent <br />Overall Standard Deviation <br />0.5 <br />Roadbed Soil Resilient Modulus (PSI) <br />5,000 <br />Structural Number <br />2.18 <br />Table 3 presents our data from core locations of the existing private drive pavement section with <br />estimated structural coefficients. Pavement design calculations are attached to this report. <br />Table 3 - Recommended Minimum Dry-Weather Pavement Section for Private Drive/Parking Lot <br />Section <br />Structural <br />Material Layer <br />Compaction Standard <br />Thicknesses <br />Coefficient <br />91%/ 92% of Rice Density <br />Asphaltic Concrete (AC) <br />3 <br />0.42 <br />AASHTO T-209 <br />Crushed Aggregate Base <br />95% of Modified Proctor <br />2 <br />0.10 <br />3/"-0 (leveling course) <br />AASHTO T-180 <br />Crushed Aggregate Base <br />95% of Modified Proctor <br />8 <br />0.10 <br />1'/2'-0 <br />AASHTO T-180 <br />95% of Standard Proctor <br />Subgrade <br />12 <br />5,000 PSI <br />AASHTO T-99 or equivalent <br />Calculated Structural Number <br />2.26 <br />The subgrade should be ripped or tilled to a depth of 12 inches, moisture conditioned, root-picked, <br />and compacted in-place prior to the placement of crushed aggregate base for pavement. Any <br />pockets of organic debris or loose fill encountered during ripping or tilling should be removed and <br />replaced with engineered fill (see Site Preparation section). In order to verify subgrade strength, <br />we recommend proof-rolling directly on subgrade with a loaded dump truck during dry weather and <br />on top of base course in wet weather. Soft areas that pump, rut, or weave should be stabilized <br />prior to paving. <br />If pavement areas are to be constructed during wet weather, the subgrade and construction plan <br />should be reviewed by the project geotechnical engineer at the time of construction so that <br />condition specific recommendations can be provided. The moisture sensitive subgrade soils make <br />the site a difficult wet weather construction project. General recommendations for wet weather <br />pavement sections are provided below. <br />18-4986, 177 Day Island Road GRPT 13 GEOPACIFIC ENGINEERING, INC. <br />Version 1, August 27, 2018 <br />