Comparative Analysis of Grillage Foundation Modeling for Lattice Transmission Towers: A Detailed Assessment of Beam Element, Shell Element and Solid Element Approaches Incorporating Soil-Structure Interaction

However, conventional analysis methods often rely on simplified beam element models, which fail to capture critical complexities such as eccentric connections, semi-rigid joints, nonprismatic members, and soil–structure interaction (SSI). These limitations can lead to inaccurate predictions of stress distribution and deflection.

This paper presents a comparative study of three modeling approaches: (1) a traditional beam element model, (2) an advanced shell element model, and (3) a detailed solid element model.

All models incorporate SSI using geotechnical data. The foundation was analyzed under maximum compression and uplift load cases using SAP2000 software. While beam element models offer quick modeling, they lack precision for detailed design relative to more detailed finite element analysis. Shell and solid element models deliver superior accuracy, albeit at a higher computational cost. Key parameters evaluated include deflections, settlements, bending moments and stress distributions. Results show that shell and solid element models provide highly consistent and accurate predictions, capturing local stress concentrations and geometric details. In contrast, the beam element model underestimates stresses in critical regions, such as bent stubs and connection zones, and fails to represent localized effects. These findings underscore the need for refined modeling approaches to improve the design reliability and structural safety of transmission tower foundations.