Effect of shape factor on sediment change around bridge piers

Scour and deposition around bridge piers are among the most common problems affecting hydraulic bridge structures. These processes are mainly controlled by the flow regime, bed material properties, sediment movement, and the geometry of the pier. In this study, the main parameters influencing bed changes around bridge piers, including pier shape, sediment transport, stream regime, channel morphology, and environmental conditions, were considered together. Based on dimensional analysis and the required experimental assumptions, the model scale, discharge, bed slope, flow velocity, sediment grain size, pier cross-sections, and test duration were determined. Laboratory experiments were then carried out using bridge pier models with different cross-sectional shapes. The aim was to investigate how the pier shape factor affects scour and deposition patterns around the piers under different flow conditions. The observed bed changes were evaluated using tables, graphs, and figures, and the relative performance of the tested pier types was compared.