Centrifuge Experiments Dealing with Monotonic and Cyclic Loads on Pile Foundations in Sand

Abstract

A clear understanding of the interaction between superstructures, foundations and the surrounding soil is crucial to enhance the resilience of existing and future Critical Infrastructure by adapting their design and maintenance. Besides the loading components already considered in the current design procedures, the foundation system can be subjected to continuous loads of a cyclic nature (e.g. wind), which are often disregarded in engineering practice even though they may trigger failure mechanisms. This limitation of the current design approach can be attributed to the scarcity of research contributions dealing with cyclic loads on pile foundations. To fill this gap, centrifuge experiments have been carried out at 50 g on piles, isolated and in groups, embedded in Hostun sand and subjected to monotonic and cyclic loads of different amplitudes and frequencies. The details of the model preparation and experimental setup of the innovative tests are presented allowing to identification of key issues in centrifuge experiments dealing with cyclic inclined and eccentric loads on model foundations. These included the manufacturing of new model piles to replicate the behaviour of reinforced concrete piles under horizontal loads which were applied throughout a specific pulley system. Preliminary results are also provided, showing accumulation of displacements during the cyclic loading paths.