Structural Response and Failure Analysis of Transmission Towers Under Foundation Sliding with Consideration of Wind Effects

To investigate the failure evolution and structural response of transmission towers under the combined effects of foundation sliding and wind loads, this study used the foundation sliding incident of Tower No. 39 on the Xiaoxing transmission line as a case for numerical back-analysis. A transmission tower model was first developed based on the finite element method, and the simulation results were compared with field observations to validate the model, with particular focus on the consistency of typical failure modes such as leg bending and cross-bracing instability. On this basis, the structural response under the combined action of foundation lateral displacement, settlement, and wind loads was further simulated. The results indicate that foundation sliding significantly affects the structural stability of transmission towers, with single-foundation sliding being more destructive than the simultaneous sliding of multiple foundations on the same side. Moreover, the coupling of foundation sliding and wind load substantially reduces the critical displacement required to trigger structural failure. Finally, critical displacement thresholds are proposed, which can serve as reference criteria for damage assessment and engineering intervention when changes in foundation conditions occur.