Numerical investigation of dynamic behavior of pile-soil systems

Pile foundation system applications have become increasingly common in recent years. Especially in high-rise buildings, it often becomes a necessity. In this thesis, the behavior of piled systems under dynamic loads is examined. The study was carried out in three stages. In the first stage, equivalent linear and nonlinear site response analyzes were performed on one and three dimensional models. In the second stage, the analyzes of linear and non-linear model piled systems under static and dynamic loads were calibrated with the findings of experimental studies in the literature. In the third stage, the calibration of the P-Y curves obtained under static horizontal loads of single pile in sandy soil in the literature with the curves obtained from the developed numerical models was carried out. At this stage, numerical models were developed and analyzes were carried out to examine the response of single and 3x3 group piles under dynamic loads of different frequencies and amplitudes. Comprehensive explanations about the path to be followed in equivalent linear and non-linear site response analysis, the interaction types that can be defined for constructing the numerical model in pile systems, and the P-multiplier parameter used in group piles are presented in the material and method section of the thesis. In the dynamic analysis of the three-dimensional models, infinite elements are used to represent non-reflective boundaries and a kinematic hardening model is used to describe the nonlinear behavior of the soil. In the light of the site response analysis and pile system analysis subject to static and dynamic effects, it has been seen that the kinematic hardening model can represent the soil behavior if the parameters are correctly calibrated. In addition, it was emphasized that the type of interaction used between the pile-soil may over- or under-estimate the horizontal and vertical bearing capacity. Finally, it was determined that in 3x3 group piles under dynamic loads, the middle row piles received less load than the front row piles at small amplitudes, but as the amplitude increased, the load on the middle row piles increased.