4805 BELVEDERE AVE 2016-01-01 MF Import

Subsurface Expinration, Crologic Hazard, and Qclvedc�e /ntr Erut Preliminary Geoterhnicaf Engineering Report Ererett, Washin ton Preliminary Design Rccommendations Footing drains must be ; rovided for ell retaining walls (including detention/infiltration vaults) as discussed under the scction on Drainoge Considerations. I[ is imperative that proper drainage be provided so that hydrostatic pressures do not develop against the walls. This would involve installation of a minimum i-foor-wide blanket drain to within 2 feet of the ground surface using imported, washed gra�•el against the walls placed to be continuous with the footing drain. 12.1 Passive Resistance and Friction Factors Lateral loads can be resisted by friction betwecn the foundation and the natural sediments or supporting stroctural fill soils, and/or by passive earth pressure acting on the buried portions of the foundations. The foundations must be backfilled with compacted strucmral fill to achieve the passive resistance provided below. Wc recommend the follcwing design parameters. • Yassive equivalent fluid = 250 pcf . Coefficient of friction = 0.35 The above ��alues arc allowable and include a factor of sa(ety of at least 2.0. 13.0 FLOOR SUPPOIZ7 Slab-on-grade flo �rs may be constructed either direcdy on the medium dense to dense or stiff to hard natural sediments, or on strucmral fill placed over these materials. Areas of the slab subgrade thai are dismrbcd (loosencd) during construction should be recompacted to an unyielding condition prior to placing the pea @ravel, as described below. If moismre intrusion through slab-on-grade iloors is to be limited, the (loors should be constructed atop a capillary break consisting of a minimum thicl:ness of 4 inches of washed pea �.ra<�el. The pca gra��el should be o��erlain by a 6-mil (minimum thicF:ness) plastic vapor retarder. In addition, a minimum of 2 inches of clean sand should be placed over the vapor retardcr to protect the integriry of the membrane during concrete placement, and to aid in the curing of the concrete. This sand layer should be kept dry prior to conerete placement. 14A DRAINAGG CONSIDERATIONS All retaining and rerimeter footing Halls should be provided with a dtain at the base o( the footing ele�ation. Urains should consist of rigid, perforated. PVC pipe surrounded by washed rca FraveL The level of the perforations in [he pipe should be set a[ or slighdy below the bottom of the footing and the drains should be conswcted with sufficient gradient to allow er.��it}� discharge ati•ay from the buildings. In addition, all retaining H�alls should be lined with a minimum 12-inch-thick w�ashed g�avel blanket that extends to w�ithin 2 feet of the surface and 1lnrrh 5, 1IX1�1 ASSOGATF.D E�1RTH SC/ENCES, INC. ,,r;.: �.�, �nr�n r,�,,.��r.��_,.r��n�e,«r�.u:A Page 18