A theoretical investigation of local scour downstream of grade-control structures based on two-dimensional jet diffusion and particle stability is experimentally verified. Turbulent jet diffusion reduces fluid velocity near the bed particles and equilibrium scour is obtained when noncohesive bed particles cannot be removed from the scour hole. Equilibrium scour depth is written as a function of...

Improved understanding of scour and sedimentation processes near and at highway bridges is dependant on collecting reliable field data. Field data collection programs, however, have been hindered by inadequacies in instrumentation and measurement technologies. Through a coordinated program of research, the Federal Highway Administration (FHWA), State Highway Agencies (SHAs), National Cooperativ...

Experimental studies to investigate the depth of the scour conducted at a side-weir intersection located at the 180 curved flume which located Hydraulic Laboratory of Yıldız Technical University, Istanbul, Turkey. Side weirs were located at the middle of the straight part of the main channel. Three different lengths (25, 40 and 50 cm) and three different weir crest height (7, 10 and 12 cm) of t...

The scour phenomenon around bridge piers causes great quantities of damages annually all over the world. Collars are considered as one of the substantial methods for reducing the depth and volume of scour around bridge piers. In this study, the experimental and numerical methods are used to investigate two different shapes of collars, i.e, rectangular and circular, in terms of reducing scour ar...

Local bridge scour is caused by the interference of bridge piers with the flow of water and is characterized by the formation of scour holes. Local scour occurs at a bridge pier when the local flow field is strong enough to remove bed materials. Several variables affect the scour depth including the flow intensity, the relative flow depth, the pier-width, and the properties of the river bed mat...

Scour is by far the primary cause of bridge failures in the United States. Scour and other hydraulic effects are particularly threatening because the deterioration is often invisible , hidden beneath turbid water. Many scour monitoring methods attempt to measure the development of scour pockets themselves. However, this is difficult due to debris — both floating and submerged — and shifting str...

This study addresses the design of riprap aprons as a scour countermeasure near abutments under clear-water conditions. It deals with the lateral extent of riprap aprons and the geometry of the scour hole prevailing at the apron edge. The study applies to riprap aprons acting as granular filters. The scour depth appears to be independent for a sufficiently long relative abutment length. Scour h...

Series of laboratory tests were carried out to study the extent of scour caused by a three-dimensional wall jets exiting from a square cross-section nozzle and into a non-cohesive sand beds. Previous observations have indicated that the effect of the tail water depth was significant for densimetric Froude number greater than ten. However, the present results indicate that the cut off value coul...

Current formulas for calculating scour depth below of a free over fall are mostly deterministic in nature and do not adequately consider the uncertainties of various scouring parameters. A reliability-based assessment of scour, taking into account uncertainties of parameters and coefficients involved, should be performed. This paper studies the reliability of a dam foundation under the threat o...

Prediction of the scour around a group of pile in the field exposed to oscillatory waves is very important for many offshore structure and coastal engineering projects. Conventional predictive formulas for the geometric properties of scour hole, however, are not able to provide sufficiently accurate results. In this paper the ANNs approach is used to predict the scour depth around pile group us...