STP670: Capacity of Axially Loaded Bent Piles in a Bearing Stratum Overlain by a Thick Layer of Soft Clay

    Wu, AH
    Soil mechanics and foundation specialist, Naval Facilities Engineering Command, Alexandria, Va.

    Fox, RR
    Professor of Civil Engineering, George Washington University, Washington, D.C.

    Pages: 14    Published: Jan 1979


    Abstract

    This paper presents a case study of four pipe piles, 35.6 cm (14 in.) outside diameter and 34.3 cm (13½ in.) inside diameter driven through a very soft sensitive clay with the pile tip embedded a short distance into a competent gravelly sand stratum. These pipe piles, 9.1 m (30 ft) to 15.2 m (50 ft), long were driven without leads due to the headroom limitation and were filled with high early strength concrete. Load tests were then performed on these piles with a known bend to failure or to the point of yielding. Results of the pile load tests, pile misalignment, soil properties, and pile-driving records were evaluated. A method of predicting the ultimate soil bearing capacity supporting the bent piles is then developed. The computed and measured ultimate pile capacities are compared and commented upon. Graphs are presented to indicate the interrelations among thickness of soft clay, geometric properties of the pile, and reduction of pile end-bearing capacity that likely occur.

    Keywords:

    bent piles, axially loaded piles, load test, ultimate soil bearing capacity, reduction of pile end-bearing capacity, soil pressure distribution against pile, wave equation, Engineering News, pile-driving formula, soft clay, dense gravelly sand


    Paper ID: STP33754S

    Committee/Subcommittee: D18.10

    DOI: 10.1520/STP33754S


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