scholarly journals Local scour around complex pier groups and combined piles at semi-integral bridge

2014 ◽  
Vol 62 (2) ◽  
pp. 108-116 ◽  
Author(s):  
Shatirah Akib ◽  
Afshin Jahangirzadeh ◽  
Hossein Basser
Keyword(s):  
Experimental Study ◽  
Laboratory Experiments ◽  
Bridge Piers ◽  
Scour Depth ◽  
Flow Depth ◽  
Flow Discharge ◽  
Integral Bridge ◽  
Integral Bridges ◽  
Equilibrium Scour Depth ◽  
The Relationship

Abstract This research presents an experimental study on the scouring mechanism at semi-integral bridge piers. Based on laboratory experiments, this study focuses on the relationship between scour depth in complex pier groups and combined piles bridge and various parameters including the variation of inflow velocity, distance, and time. 1 200 data were collected for flow velocity and scour. The flow pattern and scour were analyzed for different flow discharges and flow depths. The results showed that the scour development with respect to time was greater for higher flow depth and bigger flow discharge at semi-integral bridges. In addition, the equilibrium scour depth increased with the approach flow depth around piers at semi-integral bridges. Velocity distribution also affected the scour development. It decreased when approaching the bridge but increased from upstream to downstream of the flume.

scholarly journals Influence of Flow Shallowness on Scour Depth at Semi-Integral Bridge Piers

2011 ◽  
Vol 243-249 ◽  
pp. 4478-4481 ◽  
Author(s):  
Shatirah Akib ◽  
Faridah Othman ◽  
Mohammad Sholichin ◽  
Moatasem M. Fayyadh ◽  
S.M. Shirazi ◽  
...  
Keyword(s):  
Experimental Study ◽  
Time Evolution ◽  
Experimental Work ◽  
Bridge Piers ◽  
Scour Depth ◽  
Flow Depth ◽  
Integral Bridge ◽  
Sediment Size ◽  
Left And Right ◽  
Almost All

The paper presents the experimental study on the effect of flow shallowness on the scouring at semi-integral bridge piers. The experimental work was conducted in the Hydraulic Laboratory of University of Malaya. Out of 1020 data collected in the flow shallowness and time evolution experiments, 60 data were chosen at maximum scour depth to be analyzed. 30 data for sediment size of d50 = 0.8 mm and 30 data for d50 = 0.26 mm were taken at each side of the piers. The results showed that similar trend was produced for both sediment sizes, the depth of scour increased with the flow depth. Almost all of the data plotted gave the best correlation coefficient. The scour depth at the left and right side of the pier were almost averaged.

scholarly journals Prediction of Scour Depth Around Bridge Piers Using Evolutionary Neural Network

2018 ◽  
Vol 14 (2) ◽  
pp. 26-36
Author(s):  
Abdussamad Ismail
Keyword(s):  
Empirical Formula ◽  
Predictive Accuracy ◽  
Bridge Piers ◽  
Model Complexity ◽  
Scour Depth ◽  
Flow Depth ◽  
Mean Velocity ◽  
Critical Flow Velocity ◽  
Evolutionary Neural Network ◽  
Equilibrium Scour Depth

Abstract An empirical formula based on evolutionary regression network is proposed in this paper for predicting the equilibrium depth of scour around bridge piers. The formula expresses the equilibrium scour depth as a function of variables including flow depth and mean velocity, critical flow velocity, median grain size and pier diameter. The empirical formula is developed by training and testing an evolutionary network using scour data available in the literature. The use of the evolutionary algorithm in developing the formula is informed by the need to reduce the model complexity while sacrificing its predictive accuracy. The results of performance comparisons with existing models showed that the proposed formula model produces reasonably accurate estimates of equilibrium scour depth with a much smaller number of fitting constants compared with backpropagation neural networks.

Evaluation of Selected Pier-Scour Equations Using Field Data

1996 ◽  
Vol 1523 (1) ◽  
pp. 186-195 ◽  
Author(s):  
Mark N. Landers ◽  
David S. Mueller
Keyword(s):  
Field Measurements ◽  
Bridge Piers ◽  
Critical Ratio ◽  
Scour Depth ◽  
Flow Depth ◽  
Clear Water ◽  
Pier Scour ◽  
Logarithmic Space ◽  
State Highway ◽  
Federal Highway

Field measurements of channel scour at bridges are needed to improve the understanding of scour processes and the ability to accurately predict scour depths. An extensive data base of pier-scour measurements has been developed over the last several years in cooperative studies between state highway departments, the Federal Highway Administration, and the U.S. Geological Survey. Selected scour processes and scour design equations are evaluated using 139 measurements of local scour in live-bed and clear-water conditions. Pier-scour measurements were made at 44 bridges around 90 bridge piers in 12 states. The influence of pier width on scour depth is linear in logarithmic space. The maximum observed ratio of pier width to scour depth is 2.1 for piers aligned to the flow. Flow depth and scour depth were found to have a relation that is linear in logarithmic space and that is not bounded by some critical ratio of flow depth to pier width. Comparisons of computed and observed scour depths indicate that none of the selected equations accurately estimate the depth of scour for all of the measured conditions. Some of the equations performed well as conservative design equations; however, they overpredict many observed scour depths by large amounts. Some equations fit the data well for observed scour depths less than about 3 m (9.8 ft), but significantly underpredict larger observed scour depths.

scholarly journals ANALYSIS OF TSUNAMI SCOUR AROUND SQUARE STRUCTURES USING A PUMP-DRIVEN FLOW METHOD

2020 ◽  
pp. 8
Author(s):  
Rafael Aranguiz ◽  
Oscar Link ◽  
Jose Aliaga ◽  
Oscar Briones ◽  
Ruben Alarcon ◽  
...  
Keyword(s):  
Solitary Waves ◽  
Laboratory Experiments ◽  
Maximum Flow ◽  
Sediment Deposition ◽  
Scour Depth ◽  
Flow Depth ◽  
Field Surveys ◽  
Flow Method ◽  
Tsunami Scour ◽  
Tsunami Event

Estimation of the maximum scour depth is important for defining the size and depth of building foundations in order to avoid failure during a tsunami event (Jayaratne, et al 2016). Traditionally, tsunami scour has been studied in laboratory experiments that use solitary waves. However, it has been demonstrated that this type of wave does not represent well a real tsunami (Madsen et al, 2008). In addition, results from field surveys are based on the scour depth after the tsunami event, studying only the maximum flow depth, and ignoring other hydrodynamic features such as velocity and wave period, as well as sediment deposition. The main objective of this research is to estimate maximum tsunami scour around rectangular structures as a function of realistic tsunami variables.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/ykb-JyL7lsE

Clear-water scour at bridge piers in fine and medium gravel beds

2005 ◽  
Vol 32 (4) ◽  
pp. 775-781 ◽  
Author(s):  
Rajkumar V Raikar ◽  
Subhasish Dey
Keyword(s):  
Bridge Piers ◽  
Geometric Standard Deviation ◽  
Scour Depth ◽  
Size Factor ◽  
Clear Water ◽  
Envelope Curve ◽  
Gravel Beds ◽  
Sediment Size ◽  
Gravel Size ◽  
Equilibrium Scour Depth

An experimental investigation on scour at circular and square piers in uniform and non-uniform gravels (fine and medium sizes) under clear-water scour at limiting stability of gravels is presented. From the experimental results, it is observed that the equilibrium scour depth increases with decrease in gravel size. The variation of equilibrium scour depth with gravel sizes departures considerably from that with sand sizes. Consequently, the resulting sediment size factors for gravels, obtained from envelope curve fitting, are significantly different from the existing sediment size factor for sands. The influence of gravel gradation on scour depth is also prominent in non-uniform gravels. The time scales to represent the time variation of scour depth in uniform and non-uniform gravels are determined. For uniform gravels, the non-dimensional time scale increases with increase in pier Froude number and gravel size, whereas for non-uniform gravels, it decreases with increase in geometric standard deviation of particle size distribution of gravels.Key words: bridge pier, gravel beds, scour, erosion, sediment transport, open channel flow, hydraulic engineering.

Three-dimensional numerical simulation of local scour in the vicinity of circular side-by-side bridge piers with ice cover

2020 ◽  
Author(s):  
Mohammad Reza Namaee ◽  
Jueyi Sui ◽  
Yongsheng Wu ◽  
Natalie Linklater
Keyword(s):  
Laboratory Experiments ◽  
Transport Model ◽  
Numerical Models ◽  
Three Dimensional ◽  
Ice Cover ◽  
Local Scour ◽  
Bridge Piers ◽  
Accurate Estimation ◽  
Scour Depth ◽  
Cold Regions

Local scour around piers is one of the primary causes of collapse of bridges that cross rivers. The most severe scouring occurs in cold regions where ice cover significantly changes the velocity profile. Having an accurate estimation of the maximum scour depth around bridge piers, especially in cold regions, is necessary for a safer design of piers. In this study, 3-D numerical models are compared to laboratory experiments to examine the process of local scour around bridge piers with and without smooth and rough ice cover. By using the equation of Meyer-Peter Müller, the sediment transport model is validated to approximate the transport of the sediment particles. Numerical results showed good agreements with experimental observations where the maximum scour depth and Turbulent Kinetic Energy (TKE) around bridge piers were the highest under rough ice cover conditions.

Experimental Study on Clear Water Scour around Bridge Piers

2011 ◽  
Vol 121-126 ◽  
pp. 162-166
Author(s):  
Yao Ming Hong ◽  
Min Li Chang ◽  
Hsueh Chun Lin ◽  
Yao Chiang Kan ◽  
Chi Chang Lin
Keyword(s):  
Flow Velocity ◽  
Large Diameter ◽  
Bridge Piers ◽  
Scour Depth ◽  
Clear Water ◽  
Experimental Conditions ◽  
Cover Depth ◽  
Sediment Cover ◽  
Equilibrium Scour Depth ◽  
Fast Flow

This study analyzed the characteristics of bridge scoured by clear water according to 14 groups of laboratory experiments. The formulation of critical velocity based on historical equations of clear water scour was concluded for the test circumstances in laboratory. The experimental conditions include the variation of flow velocity, sediment cover depth, and diameter of bridge pier/bases. The erosion status prior to the maximum scour depth was recorded by a pinhole camera, and, in general, the equilibrium scour depth was reached after 24 hours. The maximum scour depth increases as the sand cover depth decreases. As the same sediment depth, the fast flow velocity will induce the deep scour depth with respect to the slow flow velocity. The same result can be observed for the large diameter of pier (or base) versus the small one. The maximum scour depths in the front of the pier are always deeper than that behind the pier.

Effects of Different Geometric Parameters of Complex Bridge Piers on Maximum Scour Depth: Experimental Study

2021 ◽  
Vol 147 (5) ◽  
pp. 04021021
Author(s):  
Habibeh Ghodsi ◽  
Mohammad Najafzadeh ◽  
Mohammad Javad Khanjani ◽  
Aliasghar Beheshti
Keyword(s):  
Experimental Study ◽  
Geometric Parameters ◽  
Bridge Piers ◽  
Scour Depth

Experimental study of the performance of a siphon sediment cleansing set in a CSO chamber

2013 ◽  
Vol 68 (1) ◽  
pp. 184-191 ◽  
Author(s):  
Yongchao Zhou ◽  
Yiping Zhang ◽  
Ping Tang ◽  
Yongmin Chen ◽  
David Z. Zhu
Keyword(s):  
Experimental Study ◽  
Area Ratio ◽  
Scour Depth ◽  
Sectional Area ◽  
Cross Sectional ◽  
Sediment Removal ◽  
Lift Capacity ◽  
Combined Sewer ◽  
Equilibrium Scour Depth ◽  
Chamber Bottom

Model experiments were conducted to investigate the performance of a siphon sediment cleansing set (SSCS) for preventing sediment deposition on the combined sewer overflow (CSO) chamber bottom. The results confirmed the effectiveness of siphon suction in sediment removal in the chamber. The sediment scour test revealed that the equilibrium scour depth correlated significantly with the siphon-lift capacity of the SSCS, which was a function of the initial siphon head and the cross-sectional area ratio between the CSO chamber and the siphon.

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