Performance of Four Foundations on End Bearing Piles

The performance of four buildings each supported on end bearing concrete-filled pipe piles is evaluated. The piles were driven through a deep deposit of soft clay and are end-bearing in stiff glacial till and weathered shale. The paper presents measurements of building settlement, pile tip settlement of both test piles and foundation piles, pore pressures induced by the pile driving, and movements of adjacent buildings on shallow foundations caused by pile driving. The pile-supported buildings settled less than 0.5 in. The main conclusions from the study are: (1) The pile design load is controlled by tip punching considerations, because the settlement of the pile tip is small until the tip-bearing capacity is approached; (2) preaugering is effective in reducing pore pressures induced by the pile driving; and (3) even with preaugering, pile driving in soft clay can cause significant movement of adjacent buildings at distances up to 50 ft.