Centrifuge Testing on Helical Piles in Sand Subjected to Pseudostatic Monotonic and Cyclic Loads

The article addresses the axial load responses of helical piles subjected to pseudo-static monotonic and incremental cycles of loads through centrifuge tests in the sand. Also, a relative comparison was made with a similar test on a conventional smooth pile with no helices. Strain gauges as instrumentations placed over pile depth provided the axial load response profiles. All tests are conducted in flight at a 20 g scale. It was observed that both smooth and helix piles had significant loss of strength due to repeated cycles. Moreover, the theoretical equations overestimate the capacity of the piles through tests in the post-cyclic monotonic loading stage. Last, the internal ultimate load and unit shaft resistance distribution are shown along the pile depth. The loss of pile resistance was consistent along the depth for the post-cyclic loading stage.