Evaluation of axial performance of tapered piles from centrifuge tests

The performance of tapered piles under axial compressive loading was invest igated using centrifuge model tests. Model tapered and cylindrical piles we re installed in cohesionless soil and subjected to axial loading. The objec tives of this study were to understand the performance characteristics of t apered piles and develop a rational approach for their design. The results of axial compressive loading tests on 12 one-tenth scale model piles with d ifferent taper angles in a centrifuge setup are presented and discussed. Si x piles were instrumented and six piles were not. The load distribution alo ng the shaft of instrumented piles was measured and the results were compar ed with an analytical solution in terms of the taper coefficient K-t. The c omparison showed a reasonable agreement between K-t values established from the experiments and those obtained from the analytical solution. A simple rational approach was proposed for the design of tapered piles. The propose d approach was used to calculate the bearing capacity of the tested piles, and reasonable agreement with the measured values was obtained. The results of this study suggest that the pile taper should be limited to the top 20- 25 pile diameters of the pile length for optimum efficiency.