one of the most concerning issues for researchers is to predict the shape and dimensions of the scour pit nearhydraulic structures such as the base of bridges, weirs, valves and stilling basins due to both financial and humanhazards induced by destruction of the structure. as the scour issue has its own complexity in relation to themultiplicity of effecting factors on it, in this study therefor...

local scour around the abutment is of utmost importance in bridge failures. numerous methods such as riprap have been proposed to reduce the destructive effects of scouring; one of the ways to harness and reduce the local scour depth is installed protective collars around the abutment. in this paper effect of collar elevation (upper level, bed level and lower level), collar geometry and its siz...

scouring is the removal of sediment particles resulted from variations of flow pattern. local scour is considered among the reasons of instability and ultimately failure of bridges. during the past decades, different methods were proposed against local scour at bridge piers. these methods can be broadly classified into two categories: flow-altering and bed-armoring methods. each method can be c...

the effect of a combined system of the bed suction and jet injection as a pier-scour countermeasure on the turbulent flow field is studied in a laboratory flume using an acoustic doppler velocimeter (adv). the three components of the velocities in the vertical symmetry plane in the equilibrium scour hole in front and rear of the pier under 3-jet injections and bed suction rate qs/q0 = 2%located...

grade control structures are hydraulic structures used to stabilize a river bed. scour downstream of this structure is the main cause of its failure. studies have developed numerous empirical relations for scour depth prediction that designers must choose between to decide the most effective equation for a specific application. this study tested the condition of submerged jets over beds of sedi...

Scour is a phenomenon that occurs as a result of natural erosion by ground water flow and transport of seabed material. In this research, scour around the legs of marine structures is simulated using the FLOW3D.V.9.3™ commercial software. The general scour model consists of two components, namely, the lift and thrust forces. The drag force, that is inserted to the structure, is a combination of...

Artificial neural networks (ANN’s) are associated with difficulties like lack of success in a given problem and unpredictable level of accuracy that could be achieved. In every new application it therefore becomes necessary to check their usefulness vis-à-vis the traditional methods and also to ascertain their performance by trying out different combinations of network architectures and learnin...

Local scour around bridge abutment is a common problem encountered worldwide. Extensive laboratory and field studies have been carried out in this field and the equations derived so far are applicable to particular circumstances only. This paper presents an alternative to the empirical equations for Prediction of Local Scour at Vertical Bridge Abutment in the form of genetic programming (GP). T...

Failure of the bridges due to local scour around their piers can cause serious life losses and property damages and create significant environmental problems. In this experimental study, scour hole geometry around circular bridge piers were investigated. The experiments were carried out in a rectangular flume 80 cm wide, 18.6 m long and 75 cm high by using uniform sediment with a median diamete...