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20 I Port of Everett—South Terminal Wharf&Electrical Upgrades—Phase 2 <br /> charts are provided for pile types that may not exist in a given pile row(example—18-inch-diameter <br /> octagonal pile—Rows A to C),but were included for information and comparison purposes. <br /> In the charts,we provide allowable compressive resistance and allowable uplift resistance versus depth <br /> below mudline. Each figure includes resistance for both static and seismic(post-liquefied)conditions. <br /> Under seismic conditions,downdrag is the result of settlement within and above the bottom of lowest <br /> liquefiable soil layer.The soil movement relative to the pile causes downward forces on the pile, resulting <br /> in additional compressive loads.The post-liquefied plots neglect skin and tip soil resistance above the <br /> bottom of the lowest liquefied layer since this portion of the profile is likely contributing to downdrag. <br /> Downdrag loads are presented in the notes section of our figures and should be added to the compressive <br /> vertical load in the post-liquefied condition. Downdrag loads should not be applied in the uplift analysis, <br /> and are included as uplift resistance. <br /> Based on the CAPWAP results,24-inch-diameter piles installed in Rows F and G have very little unit shaft <br /> resistance in the upper 20 to 30 feet below the mudline. Meanwhile, 18-inch-diameter pipe piles quickly <br /> increase in unit shaft resistance in the upper 20 to 30 feet in Row B. Based on subsurface information in <br /> this area, unit shaft and toe resistance would be expected to be similar for both rows.One hypothesis to <br /> explain this disparity is that modified installation methods are necessary near the top of the slope(Rows F <br /> to H) in order to penetrate thicker riprap slope cover in this area.The observed reduction in shaft <br /> resistance could result from probing through the upper portion of pile prior to driving the production pile. <br /> If it is in fact related to construction methods,it is likely that similar methods would be necessary for pile <br /> installation in the future, resulting in similar unit shaft capacities. <br /> Group effects need not be considered for vertical capacity of pile groups embedded in sand. <br /> Vertical Load and Displacement of Piles <br /> Springs may be used to model the nonlinear behavior between the shaft and tip of the pile under the <br /> anticipated loads.As requested for modeling soil-structure-interaction,formulas to be used in calculating <br /> the t-z(shaft)and q-z(tip)springs are provided below: <br /> The equation for t-z springs is: <br /> s 1B <br /> F — fs *rtrg * � J *As <br /> Strg <br /> Where: <br /> F= Nominal shaft resistance per foot of pile in kips per foot, <br /> fs = Nominal unit shaft resistance in ksf, <br /> rtrg =target resistance= 100%(decimal), <br /> S=incremental movement variable, <br /> Strg =movement at rtrg, <br /> 8=an exponent,0<_0<_ 1,and <br /> As=Area per foot of pile in square feet. <br /> 19232-01 NW <br /> MN <br /> December 6,2017 <br /> HARTOZOWSER <br />