A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Scour and scour protection around offshore gravity based foundations
The prediction of seabed scour around offshore gravity based foundations with complex geometries is currently a significant barrier to optimising and providing cost effective foundation designs. A significant aspect that has the potential to reduce the uncertainty and costs related to the design of these foundations is the understanding of the effect the structural geometry of the foundation has on scour. This thesis focuses on an experimental investigation of the scour and scour protection around complex structure geometries. The first part of this research considers scour under clear water conditions. During this study different foundation geometries were subjected to a range of different hydrodynamic forcings which enabled a better understanding of the scour process for these foundations. The second part of the research encompasses the design and execution of a series of experiments which investigated stability of the scour protection around such structures. The structures were tested against different combinations of wave and current conditions to determine the bed shear stress required to initiate sediment motion around each structure. This research has led to a number of novel results. The experimental investigation on scour around complex geometries showed that the scour depth around cylindrical structures (with both uniform and complex cross-sections) is linked to the depth averaged pressure gradient. Following a dimensional analysis, the controlling parameters were found to be the depth averaged Euler number, pile Reynolds number, Froude number, sediment mobility number and the non-dimensional flow depth. Based on this finding a new scour prediction equation was developed which shows good agreement with experimental and prototype scour measurements. The scour protection tests indicated that under wave dominated conditions the amplification of the bed shear stress around these structures does not exceed the value of 2. In the case of current dominated flow conditions the amplification of the bed shear ...
Scour and scour protection around offshore gravity based foundations
The prediction of seabed scour around offshore gravity based foundations with complex geometries is currently a significant barrier to optimising and providing cost effective foundation designs. A significant aspect that has the potential to reduce the uncertainty and costs related to the design of these foundations is the understanding of the effect the structural geometry of the foundation has on scour. This thesis focuses on an experimental investigation of the scour and scour protection around complex structure geometries. The first part of this research considers scour under clear water conditions. During this study different foundation geometries were subjected to a range of different hydrodynamic forcings which enabled a better understanding of the scour process for these foundations. The second part of the research encompasses the design and execution of a series of experiments which investigated stability of the scour protection around such structures. The structures were tested against different combinations of wave and current conditions to determine the bed shear stress required to initiate sediment motion around each structure. This research has led to a number of novel results. The experimental investigation on scour around complex geometries showed that the scour depth around cylindrical structures (with both uniform and complex cross-sections) is linked to the depth averaged pressure gradient. Following a dimensional analysis, the controlling parameters were found to be the depth averaged Euler number, pile Reynolds number, Froude number, sediment mobility number and the non-dimensional flow depth. Based on this finding a new scour prediction equation was developed which shows good agreement with experimental and prototype scour measurements. The scour protection tests indicated that under wave dominated conditions the amplification of the bed shear stress around these structures does not exceed the value of 2. In the case of current dominated flow conditions the amplification of the bed shear ...
Scour and scour protection around offshore gravity based foundations
Tavouktsoglou, NS (author)
2018-01-01
Doctoral thesis, UCL (University College London).
Theses
Electronic Resource
English
DDC:
500
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