Laserfiche WebLink
19 <br /> `/ %we <br /> where as and a are the pile shaft perimeter in square foot per foot of length <br /> and tip area in square feet, respectively. The ultimate tensile capacity, Qt, of <br /> a pile can be estimated: <br /> Qt gsas <br /> The above equations assume a pile of constant shaft perimeter. <br /> The allowable axial pile capacity can be determined by dividing the ultimate <br /> computed capacity by a factor of safety. The resulting allowable axial capaci- <br /> ties for individual, driven, 12- and 14-in. square, precast concrete and <br /> 12-3/8-in.-diameter steel pipe piles are shown on Plates 38 through 40. Capacity <br /> curves are shown for both locations underlain by extensive deposits of glass and <br /> locations with little or no glass. These curves include a factor of safety of <br /> 2.5. <br /> Although sand was encountered in all six, deeper borings at about El -20 to <br /> -25 ft, the sand may be locally absent in some locations. If the deeper sand is <br /> locally absent, the pile capacities shown in the sand stratum should be reduced <br /> by 40 percent. <br /> The allowable pile capacities for piles tipped in the sand can be scaled in <br /> accordance with the following formula: <br /> x - x 12 12 x 12 12 <br /> Concrete Piles: <br /> Qc (as/as ) x 0.5 Qc + (ap/ap ) x 0.5 Qc <br /> = (as/a12) x QT2 <br /> QT <br /> xx 12 12 x 12 12 <br /> Steel Pipe Piles: Qc = (as/as ) x 0.5 Q + (a P P/a ) x 0.5 Q <br /> QT = (as/as2 ) x QT2 <br /> in which: the superscript x denotes the pile under consideration, <br /> the superscript 12 denotes a 12-in.-sq concrete or 12-3/8-in.- <br /> diam. pipe pile, <br /> Qc' QT' as and a are as previously defined. <br /> 1144A/CC-19U McClelland <br />