Determining the differences in load-settlement behavior of open-ended and closed-ended piles

Piles are long, slender members that transfer load from shallow soil with a low bearing capacity to deeper soil or rock which have less compressibility and higher bearing capacity. There are two types of pipe piles: open-ended and closed-ended. It is well known that open-ended piles behave differently than closed-ended piles. The aim of this study is to investigate the difference in load-settlement behavior of open-ended and closed-ended steel pipe piles in the sand under axial loading in four different relative densities including 10%, 40%, 65%, and 90%. It is also aimed to study the ultimate bearing capacity for the same piles. For this purpose, model experiments and numerical analyses were carried out. The finite element method was also used in this research to study the behavior of the single model piles under axial loading. The obtained results show that the closed-ended piles have a higher ultimate bearing capacity than open-ended piles. For open-ended piles, the development of ultimate bearing capacity is due to the increased exterior shaft friction and soil plug inside the pile. Also, the results from experimental pile model tests and finite element analyses indicated that the ultimate bearing capacity of the model piles increases with increasing relative density. There is a good agreement between experimental results and finite element programs results.