Multi-scale structural analysis method for transmission towers considering the combined effects of multiple imperfections

To evaluate the mechanical performance of transmission towers in an economical and efficient way, this study developed a multi-scale structural analysis method for transmission towers considering the combined effects of multiple imperfections. Full-scale tower loading tests, initial bending measurements, residual deformation measurements, and material property tests were conducted on a transmission tower to characterize its structural response. Based on design drawings and measurement data, planar truss and space rigid frame models were established, and member stress ratios were calculated in accordance with relevant design standards. A series of multi-scale numerical models, including non-imperfection, single-imperfection, and multi-imperfection models, were established by incorporating shell elements, initial bending, structural residual deformation, and semi-rigid joint behavior. The accuracy of the multi-imperfection model was validated through comparative analysis. Based on this model, the failure modes and mechanical properties of the transmission tower were identified, and parametric analyses were conducted to quantify the influence of different imperfections on the structural mechanical performance. The proposed approach reduces reliance on extensive design testing and supports rapid structural assessment of in-service transmission towers.