Static and dynamic testing and design methods for driven piles in multilayered soil

This paper summarizes the results of static and dynamic pile load tests performed on fully instrumented, driven piles
in Indiana. The soil profiles at the test site locations consist of multiple layers of soils that are typical of alluvial
deposits found at bridge sites. In most of the cases considered, closed-ended and open-ended pipe piles were driven
side-by-side and tested to allow a comparison of the resistances mobilized in each layer of the soil profile and at the
bases of the piles. For robustness and redundancy of the measurements, the piles were instrumented with a dense
arrangement of electrical-resistance and vibrating-wire strain gauges along the entire length of the piles. The openended
pipe piles were specially built with a double-wall system to allow separation of the internal and external
resistances. Slow-maintained static load test protocols were followed to obtain the pile load-settlement curves with
appropriate stiffness values. The tests were performed to large pile head settlements to allow determination of ultimate
loads. Dynamic load tests were also performed to assess their ability to predict static resistances. The results of these
tests were compared with predictions made using recent hybrid CPT-based design methods and pile driving formulas
applied to measured sets during driving. An assessment of the methods of prediction or verification of ultimate
resistances is made based on the results.