1231 MADRONA AVE 2016-01-01 MF Import

� GeoloEic lnvesliEafion nnd Geofech�nl !in¢ineerrn� Itennr! � 97-01-20 r /229 hlndroiin Are. - Lo(1 � (_l�cretf, IVnshingfon Due to tlie moisture sensitivity of the site soil and to help maintain the long term stability of the adjacent slopes, collected drainage and drain lines should not be discharged upon or over site slopes. Collected water should be discharged at the base of the slope (aloirg the BNRR ditchline) or into an appropriate storm water collector system through a tightlined Fipe. Tightline pipe should consist of non-jointed, non-perforated pipe as specified in this section of the report. Surface water run-off was noted during the siie investigation. We recommend utilizing shallow french drains to collect surface water run-off along the eastern and northern sides of the proposed new home. French drains should be a maximum four (d) feet deep, two (2) feet wide, and be backfilled with 5/8" minus washed pea gravel wrapped inside of a:,trong, durable fil[er fabric. A minimum four (-!) inch perforated PVC drainline should be placed at the base of the french drain laid on a minimum 1% grade towards a point of discharge. Cleanouts should be placed at appropriate intervals to allow for adequate maintenance of the system. 4.7 Earth Pressures Behind Wall � All backfill placed behind walls or around the foundation should be placed as per the recommendations given above or within this section of the report. The following recommended earth pressures are Lpresented as equivalent fluid pressures and are based on the assumptions of a uniform, level, granular backfill without buildup of hydrostatic pressures behind walls. To minimize earth pressures and prevent �_ the buildup of hydrostatic pressures, wall backfill should consist only of free draining granular material with draina�e provisions as described above. If the backfilled walls are structurally restrained from �. lateral movement at the top, we recommend that the walis be designed for an equivalent weight of 50 pounds per cubic foot (/�c� ro represent at rest pressures. lf the tops of the walls are free to move laterally by an amount equal ro at least 0.1 percent of the wall height, they may be designed for active conditions using an equivalent FluiJ pressure of 35 pcf. Surcharges due to sloping ground, adjacent footings, vehicles, construction equipment, etc., must Ue added to these values. Only light hand-held vibratory equipment should be used to compxct soil within 5 feet of all walls. 12 GES, Inc. �