ANALYSIS AND DESIGN OF LATTICE TRANSMISSION TOWER

Abstract

The increasing demand for reliable electrical power transmission necessitates the development of structurally efficient and stable transmission tower systems. Lattice transmission towers, owing to their high strength-to-weight ratio and economic feasibility, are widely adopted in overhead power transmission networks. However, their structural behavior is complex due to the interaction of multiple loads, including dead load, wind load, and conductor forces under both normal and abnormal conditions. In the present study, a typical self-supporting lattice transmission tower is analyzed and designed using a three-dimensional space frame model developed in STAAD.Pro. The structural analysis is carried out using the finite element method to evaluate key performance parameters such as axial forces, displacements, stress distribution, and support reactions under various loading conditions. Wind load, identified as the governing load, is applied in multiple directions as per IS 875 (Part 3):2015, while design provisions are adopted from IS 802 and IS 800:2007. The results indicate that axial forces are the dominant internal forces, with maximum compressive forces occurring in the lower sections of the tower due to load accumulation. Displacement analysis shows a gradual increase along the height, with maximum deflection at the top, remaining within permissible limits. Stress distribution is found to be non-uniform, with critical stresses concentrated in main leg members, particularly under wind loading conditions. Support reactions reveal the presence of both compressive and uplift forces, emphasizing the importance of foundation design. The overall structural performance confirms that the tower satisfies both strength and serviceability criteria. The study provides a comprehensive approach to integrated load analysis and design, contributing to the development of safe, stable, and economical lattice transmission tower systems.