Steel pipe piles (12-inch diameter) are to be used as 35-ft long friction piles (i.e., pile capacity is from shaft resistance only) in an area where a deep deposit of normally consolidated clay...

Steel pipe piles (12-inch diameter) are to be used as 35-ft long friction piles (i.e., pile capacity is from shaft resistance only) in an area where a deep deposit of normally consolidated clay exists. The soil unit weight is 105 pcf. Drained shear tests indicate that the (drained) shear strength angle of internal friction, ɸ is 25°. Determine the shaft capacity using the effective stress β-method analysis (assume c = 0). Apply a factor of safety equal to 2.75.