Axial Capacity of Steel Pipe Piles in Clay

by Norman D. Dennis, Jr., (M.ASCE),
Roy E. Olson, (F.ASCE),



Abstract: Development of theories for the prediction of the axial compressive and tensile load capacities of driven piles is made difficult by a variety of factors, e.g., disturbance of the soil and changes in the state of stress caused by pile driving, dragdown of soil from one layer into another, and pile/soil interaction during loading. In the absence of a well developed theory supported by field evidence, engineers have developed a series of empirical design rules utilizing coefficients which are evaluated using full scale pile load tests. The size of data bases used in these correlations has generally been small and the methods have been applied in cases where the supporting data have been inadequate. In the terrestrial environment it is generally possible to overcome uncertainties in design by driving piles to refusal or by using pile load tests to verify design assumptions. In the case of piles driven offshore, load tests are prohibitively expensive and the use of excessively conservative design assumptions may lead to installation problems. There is, therefore, a continuing need for improvement in design methods. The improvements are needed in the complementary areas of improving the fundamental theories and improving the supporting data base and empirical correlations. We have increased the size of the readily available data base, examined the accuracy of several existing design methods, and developed improved correlations which have led to a revised design procedure.

Subject Headings: Load tests | Pile tests | Pile driving | Soil-pile interaction | Load and resistance factor design | Soil compression | Ultimate strength

 

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