<p>This work presents a numerical investigation of the damage mechanisms affecting a high-voltage transmission tower, with particular emphasis on the effects of foundation displacements on the structural response. Instead of a standard design verification, this paper proposes a forensic-predictive methodology that integrates surveying data into a nonlinear finite element environment (LS-DYNA). A detailed three-dimensional finite element model is developed to simulate the mechanical behavior of the tower and its foundation system under both design load conditions and observed support movements. The study bridges the gap between theoretical safety margins and operational reality, revealing that foundation-induced geometric non-linearities reduce the yield capacity to 60% of the design value. The aim of this work lies in the validation of a direct model updating technique that accurately predicted localized failure modes observed on-site, offering analytical insights into the coupling between foundation drift and superstructure plasticity. Based on this study, a rehabilitation strategy is proposed, consisting of foundation-level bracing and local strengthening measures, aimed at limiting differential displacements, restoring load-bearing capacity, and extending the service life of the structure.</p>