5109 SOUND AVE 2017-08-02 - Laserfiche WebLink

July 21, 2014 Two Single-Family residences L&A Job No. 14-Q65 Page 14 loading. The wall should be designed for a factor of safety of at least 1.15 against sliding failure and 1.2 against overturning failure under seismic loading. A drain line consisting of perforated, rigid PVC, drain pipes, at least 4 inches in diameter, should be installed at a few inches below bottom of retaining wall to intercept and drain away groundwater flowing towards the wall. The drain line should have sufficient slope (0.5 percent minunum) to generate flow by gravity, and w�ater collected in the drain line should be tightlined to discharge into a storm sewer or suitable stormwater disposal facilities, The drain line should be wrapped in a layer of non-woven filter fabric, such as 140NS by Mirafi Inc., or approved equal, and completely embedded in clean washed gravel or crushed rock to within about 18 inches of the finish grade. A vertical drainage blanket at least 12 inches thick, consisting of clean, 3/4 to 1-1/2-inch, washed gravel or crushed rock, should be placed against the wall. Alternatively, a vertical drain mat, such as Miradrain 6000 by Mirafi Inc., or approved equal, inay be placed against the walls as the vertical drainage blanket. The vertical drainage blanket or drain mat should be hydraulically connected to the drain line at the base of the retaining wall. Soldier Pile Wall A cantilever soldier pile retaining wall may also be constructed along the toe of the hillside as an option to stabilize the hillside. A soldier pile wall is constructed by drilling holes into the ground, inserting steel beams in the holes, and filling the holes with structural concrete. Timber boards, treated for outdoor and soil contact use, are placed against cut bank between soldier piles. The soldier pile wall should be designed for an active soil pressure of 35 pcf EFD (equivalent fluid density) plus 0.75(3 pcf, where (3 is LIU & ASSOCIATES, INC.