Letters in High Energy Physics (Feb 2024)
Finite Element Analysis of Soil-Structure Interaction in Piled Framed Structures Under Seismic Loading Conditions
Abstract
Framed structures are typically analysed by assuming either rigid or hinged bases. However, when foundations rest on deformable soils, they also undergo deformation, influenced by the relative stiffness of the foundation, superstructure, and soil. Therefore, interactive analysis is essential for accurately evaluating the superstructure's response. A logical approach to designing structures on soil must consider both the soil's deformation characteristics and the structure's flexibility. Analysing such interaction problems involves significant mathematical and computational work, often relying on elasticity, plasticity, or both. This type of analysis, which considers the flexibility of the foundation and soil, is termed "Interaction Analysis." The interaction between the structure, foundation, and soil impacts load distribution across the structural components. Previous interpretations of these interactions have used relative stiffness ratios for different parts of the system, including the superstructure's flexural rigidity, foundation elements, and soil stiffness, as key parameters for understanding the results. In this study, soil-structure interaction effects on a three-story, three-bay by two-bay space frame on a pile group embedded in soil are examined. A more rational approach is taken using finite element analysis with realistic assumptions. Initially, the frame is analysed independently with fixed column bases, followed by a separate model for the pile foundation using beam, plate, and spring elements for the piles, pile cap, and soil. The foundation stiffness obtained is then used in the interaction analysis to quantify soil-structure interaction effects on the superstructure's response. A parametric study, using the substructure approach (uncoupled analysis), explores how pile configuration, pile diameter, and soil type affect the superstructure's response. ETABS software is employed for the structural analysis. The superstructure's responses, including column moments, beam moments, and axial forces in the columns, are considered. A non-interaction analysis is also performed to assess the differences.
