Analysis of initial geometric imperfections in transmission tower structures

To clarify the influence of initial defects on transmission tower structures, this study proposes a computational methodology for quantifying initial defects in transmission tower systems, termed the Direct Defect Analysis Method (DDAM). The research framework proceeds as follows: Firstly, the classification of initial defects is systematically elaborated. Building upon existing applications of DDAM in fastener-type steel tube support systems, the methodology is extended to analyze initial geometric imperfections in transmission tower structures. Subsequently, finite element modeling is implemented using ANSYS software to numerically derive initial defect magnitudes. By employing code-specified maximum permissible deviations as evaluation criteria, the parametric configuration of equivalent initial defect parameters within the computational model is established. The results demonstrate that initial geometric defects within code-regulated global inclination limits exert negligible effects on structural performance. Such validation demonstrates the appropriateness of codified defect limits. Their application ensures structural reliability despite initial geometric deviations in transmission towers.