Structural damage, clogging, collapsing: Analysis of the bridge damage at the rivers Ahr, Inde and Vicht caused by the flood of 2021

Abstract

During the flood event in 2021 within Western Europe, many bridges were severely damaged, particularly in North Rhine-Westphalia and Rhineland-Palatinate in Germany. Within this study, a statistical analysis of the damages caused to bridges by the flood event was carried out. First, locations and damages of bridges along the rivers Inde, Vicht and Ahr were mapped. Based on these data, statistical correlations among the damage patterns were analyzed. Approximately 25 bridges along both rivers Inde and Vicht were damaged, while over 80 bridges along the Ahr were damaged. Notably, bridges located near residential areas suffered more severe damage than those in rural areas. In addition, the presence of debris played a significant role in damaging bridges. Although the bridge design did not emerge as the crucial factor, the bridge height could be determined as a contributing factor influencing the extent of damage along all three rivers. Also, the extent of damage increased as soon as overtopping of bridges occurred. Based on these findings, recommendations for the reconstruction of the numerous destroyed bridges could be identified which agree with existing literature. Additionally, recommendations regarding the estimation of 100-year design floods and the implementation of clogging into flood hazard maps were derived.