This was a Joint Industry Project (JIP) and is an adjunct to Project No. 128. The study consisted of scaled laboratory tests of model piles loaded in biased tension during simulated earthquakes under two conditions that an earlier study suggested may be critical for the design of such piles. Piles used for foundations such as those for tension-leg platforms and pile-supported hydraulic structures. These conditions, were addressed in two separate tasks, including:
(1) the presence of 'dirty' sandy soils with cohesion and cementation and
(2) the overpressures generated at the soil-water interface by the effects of the vertical component of earthquake motion.
The piles were tested in a pressure chamber and excited through soil at the base of the pressure chamber through a closed-loop, programmable testing machine. The behavior of the model piles under these conditions were analyzed using state-of-the-practice computer programs with a view toward developing a soil model that can be used in such programs by practitioners.
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