Seismic response of the pile-supported structure is strongly affected by soil–pile interaction (SPI) because the depth, properties and density of the layered soil differ for every place. In this research, a general cyclic Beam on Nonlinear Winkler Foundation (BNWF) model was developed to account for the SPI problem's essential features, including lateral load characteristics, multilayer sandy soil density and stiffness hardening/degradation. A series of tests were conducted to develop the p-y curves (called Kh-py) considering the local sand's relative densities. Strains were measured along with the single pile model under the lateral loads. The Kh-py curve was obtained based on a hyperbolic relationship for loose and dense sandy conditions. The BNWF model was subjected to seismic motions considering the site response analysis (SRA) and the soil–pile interaction (SPI) using the Kh-py and API-py curves. The model evaluation was performed on the Jahad bridge pier located in Semnan city in Iran. The seismic motion parameters were obtained based on genetic algorithms for the attenuation relationship. The dynamic analysis results in both of the py curves indicated that the maximum response values occurred almost simultaneously. The Kh-py curve considers the sand densities effect in the failure mechanism, which is shown to yield better predictions for the SPI than the API-py curves. The API-py model's obtained maximum values were decreased by 100–300% in the Kh-py model.

桩支撑结构的地震响应受到土桩相互作用（SPI）的强烈影响，因为每个地方的分层土壤的深度、性质和密度都不同。在这项研究中，开发了非线性温克勒基础 (BNWF) 模型上的一般循环梁，以解决 SPI 问题的基本特征，包括横向载荷特性、多层砂土密度和刚度硬化/退化。考虑到当地沙子的相对密度，进行了一系列测试以开发p - y曲线（称为Kh-py）。在侧向载荷下，与单桩模型一起测量应变。该枚Kh-PY曲线是基于松散和密实沙质条件的双曲线关系获得的。BNWF 模型受到使用Kh-py和API-py曲线的场地响应分析 (SRA) 和土桩相互作用 (SPI) 的地震运动影响。模型评估是在位于伊朗塞姆南市的贾哈德桥墩上进行的。基于衰减关系的遗传算法获得地震运动参数。两条py曲线的动态分析结果表明，最大响应值几乎同时出现。所述的Kh-PY曲线认为在有关故障机制，其被示出，以产生更好的预测为SPI比沙密度效果API-py曲线。的API-PY在模型的获得最大值下降了100-300％的Kh吡模型。