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Gcotechnical L:nginccring Rcport <br /> tiincle-Family Residencc <br /> I:ccrelt,\Vashinglon <br /> Deccmber 9, 2005 <br /> CG Pile No. 2017 <br /> Pagc 10 <br /> Conventional Footings: Com�cntional, shallow sprcad foundations should be founded on undisturbed, <br /> mcdium dense or better, nativc soils,or bc supported on structural fill extcnding to those soils. If P.:e snil <br /> i <br /> at the planned bottom of footing clevation is not medium dense to very dcnse, it =hould be o�•erexcavated <br /> � to expose suitab]e bearing soil, and the excavztion should be }illed rvith structural fill, or the footing may <br /> i be overpoured with cxtra concrcte. Por the doam-slope side of the planned msidence, we recommend the <br /> ' use of drill picrs,described below, to provide additional embedment relative to the slope. <br /> � Pootings shoutd extcnd at lcast 1S inches below thc ]owest adjacent finished ground surface for frost <br /> protection and bcaring capacity considerations. Intcrnational I3uilding Code (IBC) guidelines for <br /> � minimum t'oundation widths shuuld be followed for hoH� continuous and isolated spread footings. <br /> f <br /> Standiny water should not be allowed to accumulate in footing trenches. All ]oose or disturbed soil <br /> � should be remoecd from the foundation c�cavation prior to p]acing concrete. <br /> Por foundations construr,ted as outlined abot�e, �ce recommend an allowaUle dcsign bearing pressure of <br /> 2,000 pounds per square foot (ps� be used for the �ooting design. An increase of one-third is allowed <br /> , <br /> when using the altcrnate load combination in Section 1601.3.2 of the U3C that includes �aind or <br /> � carthquakc ]oads. Potential foundation sctUcment using the «commended allowable bearing pressure is <br /> estimated to be less than ]-inch total and %:-inch diffcrential betwcen footings or across a distance of <br /> yabout 30 feet. Higher soil bearing values may be appropriate for footings foundcd on the umvcathcred <br /> ouhvash, and �,vith wider footings. 'I�ese higher ��alues can be determined aRer a review of a specific <br /> ( design. <br /> i, <br /> Aeep foundations— Drillecl piers: Drilled piers can be used to support those portions of the residence, <br /> particularly for the castem do���n-slope portion of the planned foundation. The p.ers are constncted by <br /> drilling an open hole throuch any fill or loose surficial soils and into the dense nati��e soil. The hole is <br /> then immediately filled with concrcte to reduce the chance uf caving. <br /> 'Tlie bearing capacity of the piles ��ill be subject to the soil conditions encountcred, the depth into thc <br /> bearing soils, and the diameter of the pile. Since the required emUcdment dcp[h is also tied to the <br /> potentially variaUle depth of loose soils, pile depdi may cary from pile to pile. �Ve recommend drilling at <br /> ieast 5.0 feet into bearing sols. We have provided the following tables that include vertical load <br /> � capacities for scveral overall pile c�epths and diameters. <br /> � <br /> � Ccrnerstone Geotechnical, Inr,. ��/ <br /> 2`l <br /> -a';. ��' :'�" - t �'"'�'f����.�,�� � <br /> ,,.+�w $; + <br /> �..��''"'"..`�@...�r��_ . ,p�` '.�' �' _ ."' - � .c^rc � r;s �� , <br />. , a � aL` e-�- • <rY'% . - �- !� ��t , 'V ;ti e r <br /> n � <br /> i— _-�i� �� � " . .` , .rn..��':? � .v�T Y 1 . 1 <br />