The Influence of Velocity on Vulnerability of Building Structure to Debris Flow

In order to understand the possible loss of building structure to debris flow, the establishment of vulnerability is necessary. With vulnerability, the loss can be calculated. This study followed HAZUS damage state probabilities concept to establish the fragility curves of building structure under debris flow impact. It indicates the relationship of damage state probability and spectral displacement related to velocity and inundation height. In this study, the assuming inundation height and velocity were taken to establish the fragility curves, and fragility curves were integrated into a unitary curve as a proxy of vulnerability of building structure with inundation height as X-axis and loss ratio as Y-axis. In this study, the brick structure type building in Taiwan was chosen to demonstrate the concept. The vulnerabilities and possible (predicted) loss ratio of brick structure could be established under various combinations of inundation height and velocity (ranging form 2 to 20 m/s).