Assessment of Several Interpreted Pile Capacity Criteria for Large-Diameter Open-Ended Piles

What is it about?

Interpretation of field load tests on piles has many important practical considerations especially with respect to identifying the ultimate capacity of a pile. A number of interpretation criteria have been used in the past. With the increase in the use of Large-Diameter Open-Ended Piles (LDOEPs) for support of infrastructure projects it is important to ascertain that the interpretation criteria are suitable for LDOEPs. Fourteen of the most commonly used interpretation criteria were chosen for investigation in an effort to determine the best criterion to be used for LDOEPs. These methods were evaluated using a database of 68 load tests conducted on LDOEPs. The applicability of these criteria and their correlation with each was examined. The effects of the pile diameter, pile length, and the soil type on the performance of each criterion were investigated, as well as the capacity corresponding to several serviceability limit states. It was concluded that none of these methods was superior to the others, and their performance was somewhat correlated. A variation on the New York City Building Code (NYCBC) criterion is suggested for LDOEPs where the capacity is taken at the smallest settlement corresponding to: (1) the elastic compression plus 0.75 inches (20mm), (2) settlement corresponding to 5% Diameter, and (3) the settlement at plunging or strain-softening, unless modified by the Structural Engineer of Record.

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