5105 CHINOOK DR 2016-01-01 MF Import

sedimcn�s that comprise lhc corc of the slopc. BGC, plic wi11 be available to provide geotechnical engineering special inspections during the development of the project and will address any unandcipated geotec6nical conditions should they occur. Site Preparstion Site preparation for conswcdon of the planned new dcvelopment will consist of removal of the existing vegetation from the building area. Othcr than thc largc trces that may need to bc removed as part of future landscaping plans,the remaining vegelation ou�side of the building envelopc should be left intact until atter the foundation construction to providc erosion control cover during development. Soil from the foundation excavation area that will nol be used as backfill should be removed from the site or may be placod as landscaping fill around thc perimcter of the devclopment area. All 611 soil placed should be placed on horizontal benches cut into the stop�, g ground. Temporary cut slopes into the modium dense fill soils and dense sand for installation of thc foundation should be slopcd back to a l II:I V inclination. For all utility excavations decper than 4 fcct should usc a trench shield or also be sloped back during installa�'on. Cut slope inclinations may be adjusted in thc field to suit thc weather and soil wnditions at t6e time of excavation. Soil to be re-used onsitc should bc covcred with plestic shecting to rcducc the potential for erosion and sedimcnt transport and to maintain the water content of the excavated soil. Foundatioos Sprcad footing fowdations muy be usc� for fo�mdetion support of the planned additions to thc singlc family residencc. M allowable foundation hearing capacity of 2500 pounds per square foot may bc used for spread footings set to bear on the dcnse advance outwash sand sediments. A short term incrcase of one•third mey be used for wind, snow,or seismic loads. In order to key the foundation into lhe slopc, all footing shall bc excavated a minimum of 4 feet below current gra�fes to set the base of thc footin�a minimum of 2 fcet into thc dcnse sand. Anticipated settlement of the foundations placed as described should be las,s than 1 inch. BGC,pllc perform a foundation soil bcaring cvaluation prior to placing foundntion concretc to verify that the prepared f�oting subgrade complies with the recommendations in this rcport. I.atcrul loads will be resisted by friction betwecn the foundation and the supporiing soils, and/or by passivc carth pressurc actin�on thc buricd �rtions of lhe foundutions. Thc foundations must bc backfilled with fill compactcd to a medium dense, non-yielding condition to achieve thc passive resistancc providcd helow. We rccommend the following desi6m paramcters for latcral load calculations. • Passive equivelent Ouid = 250 pcf • Coefricicnt of friction = 0.30 Thc abovc valucs arc allowablc and includc a factor of s:ifely of at least 1.5. I,atcral F.arth Pr�a.9urc �'hc concretc bascmcnt rctaining walls should be dcsigncd to resist "at-rest"soil pressurc conditions as thc walls will bc fixccl at thc top and not frtx: to yield latcrally al least 0.1 perc:cnt of�thein c�iE;ht. 'f'hc walls should bc Jesigncd using and cquivalcnt (luid pressurc of 50 pounds per cubic foot (pcn. 7'hc ba5cmcnt walls should use cither a full hcight chimney drain or approved drainage bourds DGC, pllc 14267 209°i Avonue NE Woodlnvllle, WA 98077 (425) 273-5062 /' i �� CI •