Sequential failure-based fragility assessment of a transmission tower under debris flows

Abstract

This study proposes a fragility assessment framework for transmission towers under debris flow impact, emphasizing the distinct roles of front and rear legs. Using a coupled SPH-FEM approach, we simulate a wide range of debris flow scenarios (100-6,000 m3) and quantify structural damage based on plastic energy dissipation. The analysis reveals a sequential failure mechanism: front legs absorb energy and fail earlier, while rear legs engage later under higher intensity. By developing component-wise vulnerability and fragility curves with respect to debris flow potential energy, the study offers a novel perspective on transmission tower performance and enables risk-informed design for debris-prone regions.