ABSTRACT
Due to their location, across rivers and streams, bridges often interact with torrential, erosive flows, suffering (1) transient loads of high magnitude, due to flow obstruction, and (2) loss of support, due to scour. To take both components (1) and (2) into account, hazard evaluation is here based on the introduction of an integrated indicator of flood hazard intensity (IFHI). This is an extension of the existing Flood Hazard Index, which is increasingly used to map flood inundation. IFHI is appropriate for the evaluation of bridge susceptibility because it embeds the key parameters of flow velocity, flow obstruction, and sediment characteristics, in addition to inundation height. IFHI is found useful for streamlining the application of the scour hazard indicators recently included in the French guidelines (CEREMA, 2019). Combined with a high-level vulnerability model, it is implemented for a prediction of flood-induced bridge damages across the road and rail network of the Karditsa county in Central Greece. The region was the hot spot of large-scale flooding after a Mediterranean cyclone in September 2020. Comparison between predicted and observed response for 16 bridges, which were inspected after the same flood, allowed validation of the framework’s predictive accuracy across the entire range of damage levels, from minimal damage to complete failure. Results verify that IFHI is a suitable hazard indicator yielding reasonably accurate predictions of bridge response to flood hazard impacts, for engineering applications.
