Measuring the geometry of a developing scour hole in clear-water conditions using underwater sonar scanning

2020 ◽  
Vol 35 (1) ◽  
pp. 105-114
Author(s):  
Ashley Rogers ◽  
Costantino Manes ◽  
Toru Tsuzaki
Keyword(s):  
Clear Water ◽  
Water Conditions ◽  
Scour Hole

Pressure flow and weir scour beneath a bridge deck

2019 ◽  
Vol 46 (6) ◽  
pp. 534-543
Author(s):  
Musteyde Baduna Kocyigit ◽  
Onur Karakurt
Keyword(s):  
Bridge Deck ◽  
Flow Depth ◽  
Clear Water ◽  
Hole Depth ◽  
Sediment Size ◽  
Bridge Model ◽  
Weir Flow ◽  
Water Conditions ◽  
Scour Hole ◽  
Series Of Experiments

In this study, a series of experiments in a flume was conducted to investigate the maximum scour hole depth that occurred due to the vertical contraction of the flow underneath a bridge deck model without a pier. The bridge model was tested under pressurized and weir type of flows governed by clear water conditions. Various parameters of flow, sediment, and geometric features of the bridge, such as approach flow depth, discharge, sediment size, girder depth and degree of submergence were varied to investigate their effects on the maximum depth of scour hole. A total of 102 experiments were conducted and two empirical equations were developed separately for pressure and weir flow types with the use of experimental data. Effects of the aforementioned parameters on the scour hole were also analyzed and discussed.

scholarly journals Non-Intrusive Underwater Measurement of Local Scour Around a Bridge Pier

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2063 ◽  
Author(s):  
Poggi ◽  
Kudryavtseva
Keyword(s):  
Low Cost ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Laser Source ◽  
Scour Depth ◽  
Spatial Evolution ◽  
Clear Water ◽  
Water Conditions ◽  
Scour Hole ◽  
Temporal And Spatial

A non-intrusive low-cost technique for monitoring the temporal and spatial evolution of the scour hole around bridge piers is presented. The setup for the application of the technique is simple, low-cost and non-intrusive. It couples a line laser source and commercial camera to get a fast and accurate measurement of the whole scour hole in the front and behind the bridge pier. A short campaign of measurements of the scour hole around a bridge pier in clear-water conditions is presented to provide a control test and to show how to apply the new method. Finally, the results are compared with two of the most used equations, for the time evolution of the maximum scour depth in clear-water conditions, to show the effectiveness of the proposed technique.

Riprap Performance at Bridge Piers Under Mobile-Bed Conditions

1998 ◽  
Vol 1647 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Carlos Toro-Escobar ◽  
Richard Voigt ◽  
Bruce Melville ◽  
Meng Chiew ◽  
Gary Parker
Keyword(s):  
Experimental Tests ◽  
Bridge Piers ◽  
Design Criteria ◽  
Research Groups ◽  
Clear Water ◽  
Pier Scour ◽  
Mobile Bed ◽  
Water Conditions ◽  
Improved Design ◽  
Flood Flow

Design criteria for riprap at bridge piers in rivers is based on the specification of a size, gradation, and cover that does not fail under an appropriately chosen flood flow. Experimental tests of riprap performance at bridge piers to date have relied on a configuration for which the ambient bed is not mobilized, that is, clear-water conditions. In the field, however, riprap is, as a rule, subjected to mobile-bed conditions during floods. Recent experiments by three cooperating research groups (University of Auckland, Nanyang University, and St. Anthony Falls Laboratory) indicate a heretofore unrecognized mechanism for riprap failure under mobile-bed conditions. When the flow is in the dune regime, the passage of successive dunes causes riprap that is never directly entrained by the flow to sink and disperse. Pier scour is realized as a consequence of these processes. In some cases, the depth of scour realized is not significantly less than that which would occur without riprap. When the riprap is fully underlain by a geotextile, edge effects can cause local removal of riprap, upturning of the geotextile, and general failure. When the riprap is underlain by a partial geotextile (i.e., one that covers an area less than the riprap), edge scour causes local sinking that anchors the geotextile. The sinking and dispersion of the rest of the riprap are greatly limited, and the riprap fails only when flow velocities are sufficient for direct entrainment. The experiments suggest improved design criteria for the installation of riprap in the field.

An initial assessment of bed destabilization risk past vegetation patches using instrumented particles

2021 ◽  
Author(s):  
Yi Xu ◽  
Valyrakis Manousos ◽  
Panagiotis Michalis
Keyword(s):  
Initial Assessment ◽  
Flow Structures ◽  
Clear Water ◽  
Flow Conditions ◽  
Flow Parameters ◽  
Water Conditions ◽  
The Mean ◽  
Acoustic Doppler Velocimetry ◽  
Patch Density ◽  
Vegetation Patches

<p>Instream vegetation may alter the mean and turbukent flow fields leading to destabilizing riverbed surface, under certain flow conditions. In particular, recent research on instream vegetation hydrodynamics and ecohydrogeomorphology has focused on how energetic flow structures and bulk flow parameters downstream a vegetation may result in riverbed destabilization. This study, demonstrated the application of a 20mm novel instrumented particle in recording entrainment rates downstream simulated vegetation patches of distinct densities, at various distances downstream these. A patch of 6mm acrilic cylinders is used to simulate the emergent vegetation having the same diameter (12cm) and different porosities or densities (void volume equal to 1.25%, 3.15%, 6.25%, 11.25%, and 17.25%). The flow velocity near the instrumented particle is recorded using acoustic Doppler velocimetry (ADV) with appropriate seeding, under clear water conditions. Preliminary results are presented with focus on the effect of vegetation patch density on the flow field and subsequent effects on particle entrainment rates and implications for bed surface destabilisation.</p>

Kinetics of bacteria inactivation employing UV radiation under clear water conditions

2006 ◽  
Vol 121 (2-3) ◽  
pp. 135-145 ◽  
Author(s):  
M LABAS ◽  
R BRANDI ◽  
C MARTIN ◽  
A CASSANO
Keyword(s):  
Uv Radiation ◽  
Clear Water ◽  
Bacteria Inactivation ◽  
Water Conditions ◽  
Kinetics Of

Conception et performance d'un champ d'épandage de grandes dimensions

1988 ◽  
Vol 15 (2) ◽  
pp. 216-222 ◽  
Author(s):  
Robert P. Chapuis
Keyword(s):  
Service Life ◽  
Ground Water ◽  
Infiltration Rate ◽  
Full Scale ◽  
Full Scale Test ◽  
Clear Water ◽  
Good Design ◽  
Water Conditions ◽  
Evaporation Losses ◽  
Scale Test

A large disposal field (31 × 69 m) was designed in agreement with legal recommendations. A full scale test with clear water revealed that the field exfiltration rate was much lower than anticipated. This paper describes the design, the instrumentation performed with eleven piezometers, the ground-water conditions as modified by the disposal field, how the true exfiltration rates have been determined after due consideration of natural precipitations and evaporation losses, and also the method used to improve the performance. The value of the infiltration rate into the soil, initially established by percolation tests, was confirmed by permeability tests performed in the piezometers. However, the true exfiltration rate of this disposal field was only 8% of the rate predicted by the conventional, legal design. It is established that this exfiltration rate cannot be derived by simple transposition of the results of percolation tests as presently done by by-laws. Alternatively, more rigorous methods are described. For a good design, it is necessary to perform hydrogeologic studies much more detailed than those presently required by by-laws. Finally, for improving the design and service life of such disposal fields, several suggestions are made to avoid water mounds and to reduce the risk of clogging.

scholarly journals The effect of tetrahedron framed permeable weirs on river bed stability in a mountainous area under clear water conditions

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Jia-mei Wang ◽  
Xing-guo Yang ◽  
Hong-wei Zhou ◽  
Zi-hao Wang ◽  
Jia-wen Zhou ◽  
...  
Keyword(s):  
Mountainous Area ◽  
Clear Water ◽  
River Bed ◽  
Water Conditions ◽  
Bed Stability

scholarly journals Effect of L-shaped slots on scour around a bridge abutment

2021 ◽  
Author(s):  
Neveen Y. Saad ◽  
Ehab M. Fattouh ◽  
M. Mokhtar
Keyword(s):  
Laboratory Experiments ◽  
Vertical Wall ◽  
Clear Water ◽  
Flow Conditions ◽  
Bridge Abutment ◽  
Scour Hole ◽  
Bed Materials ◽  
Bridge Failure ◽  
Study Laboratory ◽  
Area And Volume

Abstract Local scour is the most significant cause of bridge failure. Providing a short abutment with a straight slot has proved to be an effective method for reducing scour at this abutment. In this study, laboratory experiments have been conducted to investigate the effectiveness of using L-shaped slots in comparison to the commonly used straight slot, on the scour reduction at short vertical-wall abutment under clear-water flow conditions and uniform bed materials. The slots were just above the bed and their diameters equal to half the abutment's length. The results illustrated that it is essential to have a straight slot in any combination of slots, as any configuration without one is inefficient. Also, a combination of a straight slot with one side slot in the middle of the abutment's width gives better performance than an individual straight slot, as it reduces the depth, area, and volume of the scour hole by about 32.6, 26.8, and 43.6% respectively, in comparison to 23.2, 20.7, and 35.3% for the straight slot alone.

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