Author(s): Isabella Schalko; Lukas Schmocker; Robert M. Boes; Volker Weitbrecht
Keywords: Ccumulation probability; Flood protection; Flood risk assessment; Large wood (LW); River engineering
Abstract: River infrastructures like bridges are prone to accumulations of transported large wood (LW) during floods. To contribute to an improved risk evaluation, the prediction of LW accumulation probability (AP) is crucial. Previous studies on LW AP focused mainly on the influence of a bridge deck. In the present study, flume experiments were conducted to investigate LW AP at bridge piers with special emphasis on (1) approach flow conditions, (2) bridge pier characteristics with different pier roughness, shape, diameter, and pier number, (3) LW characteristics, involving various log lengths, log diameter, log density, LW with and without branches, and uncongested versus (semi-) congested LW transport, and (4) channel bed, i.e. scour. Based on the experiments, AP is mainly a function of approach flow velocity and log length. The results were combined in a design equation to predict AP for risk assessment in engineering application.