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Geotechnical Engineering Report 8 May 25,2017 <br /> Central Everett CHC,Everett,Washington RGI Project No.2017-094 • <br /> The allowable foundation bearing pressures apply to dead loads plus design live load <br /> conditions. For short-term loads, such as wind and seismic, a 1/3 increase in this <br /> allowable capacity may be used. At perimeter locations, RGI recommends not including <br /> the upper 12 inches of soil in the computation of passive pressures because it can be <br /> affected by weather or disturbed by future grading activity. The passive pressure value <br /> assumes the foundation will be constructed neat against competent soil or backfilled with <br /> structural fill as described in Section 5.2.5. The recommended base friction and passive <br /> resistance value includes a safety factor of about 1.5. <br /> Perimeter foundations exposed to weather should be at a minimum depth of 18 inches <br /> below final exterior grades. Interior foundations can be constructed at any convenient <br /> depth below the floor slab. Finished grade is defined as the lowest adjacent grade within <br /> 5 feet of the foundation for perimeter (or exterior) footings and finished floor level for <br /> interior footings. <br /> With spread-footing foundations designed in accordance with the recommendations in <br /> this section, maximum total and differential post-construction settlements of 1 inch and <br /> 1/2 inch, respectively, should be expected. <br /> 5.3.2 MicRo PILES <br /> RGI understands that the design team is considering using micro piles to support the <br /> column loads including uplift. <br /> A micro pile is basically vertical soil nail and typically consists of 3/4- to 1-3/8-inch- <br /> diameter steel bars that are centrally grouted in 6- to 8-inch-diameter augered holes. <br /> Based on the soil encountered, a shaft resistance of 1,500 psf can be used for micro pile <br /> design. RGI recommends not including the upper 2 feet of soil in the computation of pile <br /> capacity because it can be affected by weather or disturbed by future grading activity. <br /> The shaft resistance assumes open hole tremie grouting. A pile load test is recommend to <br /> verify the soil resistance before construction. The design capacities listed in Table 5 can <br /> be used in design. The design capacities assume a pile depth of 20 feet bgs. <br /> Table 5 Micro Pile Capacities (kips) <br /> Rrle Typ ,P lCire h amete�(� c ,, o p essi© Uplif6 r l Lateral* ;' <br /> Micro Pile 6 45 42 I 5 <br /> Micro Pile 862 56 6 <br /> *Lateral load assumes 1"top deflection. <br /> II I <br /> l <br /> RILEYGROUP <br />