Laserfiche WebLink
• <br /> • <br /> nNFELDER <br /> • Bright People.Right Solutions. <br /> • <br /> • values should not exceed 1,500 psf. The upper 2 feet of passive pressure should be neglected <br /> • unless the ground surface is protected by pavements or concrete. An allowable coefficient of <br /> • friction of 0.30 between the base of the footings, or slabs founded on grade, and the engineered <br /> • fill soils can be used for sliding resistance using the dead load forces. Friction and passive <br /> • resistance may be combined without reduction. <br /> • <br /> • 4.2.3 Short Drilled Piles for Building Improvements <br /> • <br /> • Axial Capacity <br /> The downward axial capacity of drilled piles may be computed based on an allowable skin <br /> friction capacity of 150 pounds per square foot and an allowable end bearing capacity of 3,000 <br /> • pounds per square foot. We recommend that the load carrying capacity of the soils in the upper <br /> • 2 feet of the subsurface be neglected when using the IBC method or rational methods to <br /> • account for surface disturbance. End bearing should be neglected in existing fill soils. The uplift <br /> • capacity may be taken as one-half the downward allowable axial capacity and a one-third <br /> • increase in the allowable capacities may be used for wind or seismic loads. <br /> • <br /> • Lateral Loads <br /> • For computing the lateral resistance, drilled pier foundations can be designed in general <br /> • accordance with Section 1807.3 of the 2018 IBC. We recommend an allowable lateral soil <br /> • bearing pressure of 250 pounds per square foot (psf) per foot of depth below grade. The <br /> • allowable lateral soil bearing pressure should not exceed 1,500 psf. Since drilled piles are <br /> • isolated pole foundations, the allowable lateral soil bearing pressure may be increased by a <br /> • factor of 2 for short-term lateral loads provided the structure will not be adversely affected by <br /> • 1/2 inch of movement at the ground surface. We recommend that the passive resistance of the <br /> • soils in the upper 2 feet of the subsurface be neglected due to the potential for soil disturbance. <br /> • <br /> Estimated Settlement <br /> • Settlement of the proposed foundation supported on drilled piles, as recommended, is estimated <br /> to be less than '/2 inch. This value does not include elastic compression of the piles under <br /> • design loads. <br /> • <br /> • <br /> • <br /> • <br /> ID 20203884.001A/SEA20R110164 Page 13 of 28 June 1, 2020 <br /> ©2020 Kleinfelder <br /> • <br /> I <br />