Author(s): Diego Panici, Gustavo A. M. De Almeida
Linked Author(s): Diego Panici
Keywords: Bridge pier, flood risk, woody debris, debris jam, bridge clogging
Abstract:
Woody debris accumulations at bridge piers can significantly increase the risk of flooding and bridge failure due to increased afflux upstream of bridges, additional structural loads and exacerbated scour. Despite the importance of this problem, limited research has been conducted on the topic. In this study, we experimentally analyse the process of accumulations of woody debris (modelled with twigs and natural sticks) at single piers exposed to flow and a continuous debris supply. Results show that these debris jams follow a three-phase growth: unstable (where growth occurs rapidly but debris are easily disengaged); stable (growth assumes a less pronounced trend and debris are less likely to be escaped); critical (the accumulation begins to oscillate about the pier and ultimately drifts away, i.e. fails). The dimensions of the accumulation at failure are observed to plot as well-defined functions of the flow and debris characteristics. In particular, while the cross-sectional and longitudinal dimensions of the accumulations are observed to decrease with increasing flow, the vertical component displayed an opposite trend. These results provide a worst-case scenario that can be useful for engineering bridge design and flood risk assessment. (2613, 65, 294)
Year: 2017