Lateral Capacity of Step-Tapered Piles in Sand Deposits

Abstract

AbstractMany structures on pile foundations, especially in the marine environments are subjected to lateral loads from the impact of berthing ships, sea waves, wind, etc. Piles are mostly used with straight-sided walls or circular ones. However, in recent days enlarged, top cross-section, step-tapered piles are found to be of interest and advantageous over traditional deep foundation systems. Step-tapered pile foundation is a relatively new structure and is such a kind of pile foundation having its cross-section decreased in steps. In this study, the characteristics of step-tapered piles were established from the experimental investigation, under lateral loadings. The tests were carried out on straight and step-tapered piles of different segments, 650 mm long embedded in homogenous and layered sand deposits. The piles were instrumented along their length to know their behaviour along with the depth. In order to examine the ultimate lateral capacity and the deflection, the tests were carried out to failure. The test results indicated a non-linear response and a substantial increase in lateral capacity of the pile with decreased deflections for step-tapered piles. The provision of providing steps or segments for piles with five segments resulted in an increase in the load capacity ranging between 44 and 73% in a layered condition and 42–63% in a homogenous sand condition. Providing segments shows a significant effect on load-bearing capacity. Step-tapered piles experienced lesser deflection at the pile head and also along the shaft when compared to the uniform diameter pile and they have better material distribution leading to overall efficiency.KeywordsStep-tapered pilesHomogenous sandLayered sandUltimate lateral capacityDeflections