Preliminary Geotechnical Engineering Report <br />Project No. 18-4986, 177 Day Island Road, Eugene, Oregon <br />NO " <br />Water collected from the wall drains should be directed into the local storm drain system or other <br />suitable outlet. A minimum 0.5 percent fall should be maintained throughout the drain and non- <br />perforated pipe outlet. Down spouts and roof drains should not be connected to the wall drains in <br />order to reduce the potential for clogging. The drains should include clean-outs to allow periodic <br />maintenance and inspection. Grades around the proposed structure should be sloped such that <br />surface water drains away from the building. <br />GeoPacific should be contacted during construction to verify subgrade strength in wall keyway <br />excavations, to verify that backslope soils are in accordance with our assumptions, and to take <br />density tests on the wall backfill materials. <br />Structures should be located a horizontal distance of at least 1.5H away from the back of the <br />retaining wall, where H is the total height of the wall. GeoPacific should be contacted for additional <br />foundation recommendations where structures are located closer than 1.5H to the top of any wall. <br />Drainage <br />The upslope edge of perimeter footings may be provided with a drainage system consisting of <br />3-inch diameter, slotted, plastic pipe embedded in a minimum of 1 W per lineal foot of clean, free- <br />draining gravel or uncompacted 3/4"-0 rock. Water collected from the footing drains should be <br />directed into the local storm drain system or another suitable outlet. A minimum 0.5 percent fall <br />should be maintained throughout the drain and non-perforated pipe outlet. Down spouts and roof <br />drains should not be connected to the foundation drains in order to reduce the potential for <br />clogging. The footing drains should include clean-outs to allow periodic maintenance and <br />inspection. Grades around the proposed structure should be sloped such that surface water drains <br />away from the building. Footing drain recommendations are given to prevent detrimental effects of <br />groundwater on foundations and should not be expected to eliminate all potential sources of water <br />entering a crawlspace. An adequate grade to a low point outlet drain in the crawlspace is required <br />by code. <br />Flexible Pavement Design: Private Drive and Parking Lot <br />We understand that development at the site will include construction of a parking lot associated <br />with the proposed apartment building. We assume that traffic will primarily consist of light duty <br />residential cars, weekly trash pickups, and occasional fire trucks. We assumed an 18-kip ESAL <br />count of 26,624 over 20 years, accounting for projected population growth. Table 2 presents our <br />flexible pavement design input factors. <br />18-4986, 177 Day Island Road GRPT 12 GEOPACIFIC ENGINEERING, INC. <br />Version 1, August 27, 2018 <br />