STP670: Failure During Construction and Subsequent Rehabilitation and Performance of a Dynamically Cast-in-Place Concrete Pile Foundation

    Clark, JI
    Vice President, Technical Services, R. M. Hardy and Associates, Ltd., Calgary, Alberta

    Pages: 22    Published: Jan 1979


    Abstract

    During construction of a dynamically cast-in-place concrete pile foundation for a heavily loaded library tower at the University of Calgary, extensive pile heave was recorded. Consultants were engaged to assess the effect of pile heave on the pile capacity. A down-hole sonic tool was used to assess several piles where damage was suspected, and the results indicated severe damage to the pile shafts. Load tests confirmed the results when piles failed at a fraction of the required load. Further assessment led to the conclusion that 200 of the total of 292 piles were not capable of supporting the design load.

    The contractor elected to rehabilitate the damaged piles by adopting a pressure grouting technique recommended by the consultants. Load tests confirmed the viability of the grouting method, and it was implemented for all damaged piles. During the rehabilitation, extensive fracturing of the soil was revealed at various depths over the entire building site. The piles were successfully rehabilitated, and the structure was instrumented to record settlement during and after construction. Settlement records have been maintained for seven years since construction.

    Keywords:

    piles, dynamically cast-in-place expanded base concrete piles, pile heave, cohesive soils, sonic tests, pile load tests, grouting, pile rehabilitation, settlement observations


    Paper ID: STP33730S

    Committee/Subcommittee: D18.05

    DOI: 10.1520/STP33730S


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