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Effect of sediment density in bridge pier scour experiments
The estimation of scour depth at bridge piers is an important task in hydraulic engineering. The physical processes governing bridge scour range are highly complicated and several open questions still await clarification. This is reflected by the multitude of available approaches which yield significant differences in estimated scour depths up to several meters. Most of the existing approaches were derived on the basis of scale model experiments carried out in the laboratory with simplified boundary conditions. However, for fine sized prototype sediments such as sand it is often not possible to downscale the sediment due to associated changes in physical and chemical properties once the scaled sediment is in the silt and clay range. The objective of this thesis is to investigate the possibility to substitute natural sediment by artificial granulate. For this purpose, scour experiments were carried out in an 8.0 m long, 0.3 m wide and 0.6 m deep horizontal flume. A single cylindrical pier model with diameter D = 0.03 m was embedded vertically in the flume centerline. The scour experiments were carried out with natural and artificial sediments. As a result, two points can finally be summarized. First, the material density has significant influence on the time to reach the equilibrium scour depth, but not on the maximum scour depth. Second, if artificial granulate with a lower density is used in a bridge pier model instead of natural sediment, the grain size should be similar to get similar scour depth.
Effect of sediment density in bridge pier scour experiments
The estimation of scour depth at bridge piers is an important task in hydraulic engineering. The physical processes governing bridge scour range are highly complicated and several open questions still await clarification. This is reflected by the multitude of available approaches which yield significant differences in estimated scour depths up to several meters. Most of the existing approaches were derived on the basis of scale model experiments carried out in the laboratory with simplified boundary conditions. However, for fine sized prototype sediments such as sand it is often not possible to downscale the sediment due to associated changes in physical and chemical properties once the scaled sediment is in the silt and clay range. The objective of this thesis is to investigate the possibility to substitute natural sediment by artificial granulate. For this purpose, scour experiments were carried out in an 8.0 m long, 0.3 m wide and 0.6 m deep horizontal flume. A single cylindrical pier model with diameter D = 0.03 m was embedded vertically in the flume centerline. The scour experiments were carried out with natural and artificial sediments. As a result, two points can finally be summarized. First, the material density has significant influence on the time to reach the equilibrium scour depth, but not on the maximum scour depth. Second, if artificial granulate with a lower density is used in a bridge pier model instead of natural sediment, the grain size should be similar to get similar scour depth.
Effect of sediment density in bridge pier scour experiments
Einfluss der Sedimentdichte in Pfeilerkolk Experimenten
Meyering, Henrich (author) / Universitätsbibliothek Braunschweig (host institution) / Dittrich, Andreas (tutor)
2012
Miscellaneous
Electronic Resource
English
DDC:
627