Effect of Collars on the Downstream Movement of the Maximum Scour Depth Location Around Bridge Abutments and Piers

2021 ◽  
Author(s):  
Serife Yurdagul Kumcu ◽  
Mehmet Ali Kokpinar ◽  
Mustafa Gogus
Keyword(s):  
Scour Depth ◽  
Bridge Abutments ◽  
Downstream Movement

Local scour around bridge abutments including effects of relative bed coarseness and blockage ratio

2016 ◽  
Vol 43 (1) ◽  
pp. 51-59
Author(s):  
Peng Wu ◽  
Ram Balachandar
Keyword(s):  
Strong Influence ◽  
Empirical Equation ◽  
Local Scour ◽  
Experimental Results ◽  
Scour Depth ◽  
Blockage Ratio ◽  
Flow Depth ◽  
Bridge Abutments ◽  
Additional Support

Based on laboratory scale experiments, the role of relative bed coarseness, approach flow depth, and blockage ratio on local scour around semi-circular bridge abutments are discussed. The results reveal that the approach flow depth and relative bed coarseness have a very strong influence on the scour geometry. With the increase of relative bed coarseness, the scour width and scour depth decrease correspondingly. Larger blockage ratios result in larger scour but the relative effects is the smallest compared to the approach flow depth and relative bed coarseness. An empirical equation is developed based on the experimental results. The study provides additional support for considering relative bed coarseness, flow depth, and blockage ratio in scour prediction formulae.

scholarly journals ANFIS-based approach to scour depth prediction at abutments in armored beds

2010 ◽  
Vol 13 (4) ◽  
pp. 699-713 ◽  
Author(s):  
Mohammad Muzzammil ◽  
Javed Alam
Keyword(s):  
Fuzzy Inference ◽  
Accurate Estimation ◽  
Scour Depth ◽  
Bridge Abutments ◽  
Anfis Model ◽  
Inference System ◽  
Depth Prediction ◽  
Neuro Fuzzy ◽  
Artificial Neural Network Ann ◽  
The Comparative Study

An accurate estimation of the maximum possible scour depth at bridge abutments is of paramount importance in decision-making for the safe abutment foundation depth and also for the degree of scour countermeasures to be implemented against excessive scouring. Most of the scour depth prediction formulae available in the literature have been developed based on the analysis of laboratory and field data using statistical methods such as the regression method (RM). The alternative approaches, such as artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS), are generally preferred to provide better solutions in cases where the available data is incomplete or ambiguous in nature. In the present study, an attempt has, therefore, been made to develop the ANFIS model for the prediction of scour depth at the bridge abutments embedded in an armored bed and make the comparative study for the performance of ANFIS over RM and ANN in modeling the scour depth. It has been found that the ANFIS model performed best amongst all of these methods. The causative variables in raw form result in a more accurate prediction of the scour depth than that of their grouped form.

scholarly journals ANFIS approach to the scour depth prediction at a bridge abutment

2010 ◽  
Vol 12 (4) ◽  
pp. 474-485 ◽  
Author(s):  
Mohammad Muzzammil
Keyword(s):  
Fuzzy Inference ◽  
Accurate Estimation ◽  
Scour Depth ◽  
Bridge Abutments ◽  
Anfis Model ◽  
Inference System ◽  
Model Studies ◽  
Depth Prediction ◽  
Bridge Abutment ◽  
Conventional Regression

An accurate estimation of the maximum possible scour depth at bridge abutments is of paramount importance in decision-making for the safe abutment foundation depth and also for the degree of scour counter-measure to be implemented against excessive scouring. Despite analysis of innumerable prototype and hydraulic model studies in the past, the scour depth prediction at the bridge abutments has remained inconclusive. This paper presents an alternative to the conventional regression model (RM) in the form of an adaptive network-based fuzzy inference system (ANFIS) modelling. The performance of ANFIS over RM and artificial neural networks (ANNs) is assessed here. It was found that the ANFIS model performed best among of these methods. The causative variables in raw form result in a more accurate prediction of the scour depth than that of their grouped form.

Temporal scour development at bridge abutments with a collar

2007 ◽  
Vol 34 (4) ◽  
pp. 549-556 ◽  
Author(s):  
Şerife Yurdagül Kumcu ◽  
Mustafa Gögüş ◽  
Mehmet Ali Kökpinar
Keyword(s):  
Temporal Variation ◽  
Vertical Wall ◽  
Scour Depth ◽  
Clear Water ◽  
Flow Conditions ◽  
Bridge Abutments ◽  
Time Period ◽  
Bridge Abutment ◽  
Laboratory Flume ◽  
Sediment Particles

This study investigated the reduction of scour around a vertical-wall bridge abutment using rectangular collars for clear-water flow conditions over uniform sediment particles in a laboratory flume. Collars of different sizes and at different elevations were tested to determine the temporal variation of scour depth around the bridge abutment. The development of scour around the abutments with and without a collar for a time period of 6 h was studied, and observed scour depths were compared. Experimental results showed that, in addition to protecting the abutments against erosion, the addition of a collar is effective in reducing the rate of temporal scour development. A comparison of the present results with those from previous studies revealed that the effectiveness of a collar increases with a decrease in the elevation of the collar and an increase in the width of the collar.Key words: bridge abutment, collar, experimentation, hydraulics, scour, temporal variation.

Further studies of incipient motion and shear stress on local scour around bridge abutment under ice cover

2014 ◽  
Vol 41 (10) ◽  
pp. 892-899 ◽  
Author(s):  
Peng Wu ◽  
Faye Hirshfield ◽  
Jueyi Sui
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Shear Stress ◽  
Open Channel ◽  
Ice Cover ◽  
Scour Depth ◽  
Incipient Motion ◽  
Clear Water ◽  
Bridge Abutments ◽  
Bridge Abutment

An experimental study was conducted to investigate the scour development around bridge abutments under ice cover with non-uniform natural sands. Two abutments and three non-uniform sediments were used in the research. The mechanism of incipient motion for non-uniform sediments under ice cover was analyzed. By introducing scour angles around two abutments, a relationship between maximum scour depth and velocity was established for clear-water scour under ice cover. Dimensionless shear stress was also calculated and compared with shear Reynolds number for non-uniform sediments. The maximum scour depth and dimensionless shear stress were investigated under both open channel, smooth cover and rough covered conditions. Results show that around the square abutment, the scour angle is smaller than that of the semi-circular abutment. For clear water scour, the maximum scour depth increases due to the presence of ice cover.

Maximum scour depth at bridge abutments terminating in the floodplain zone

1997 ◽  
Vol 24 (6) ◽  
pp. 996-1006 ◽  
Author(s):  
S. Kouchakzadeh ◽  
R.D. Townsend
Keyword(s):  
Scour Depth ◽  
Bridge Abutments

Clear-Water Scour around Bridge Abutments under Backwater Conditions

1996 ◽  
Vol 1523 (1) ◽  
pp. 196-202 ◽  
Author(s):  
Terry W. Sturm ◽  
Aftab Sadiq
Keyword(s):  
Flow Distribution ◽  
Scour Depth ◽  
Clear Water ◽  
Bridge Abutments ◽  
Bridge Abutment ◽  
Rectangular Channels ◽  
Contraction Ratio ◽  
Bridge Approach ◽  
Contraction Scour ◽  
Abutment Scour

An experimental study was conducted of the depth of clear-water scour around the end of a square-edged bridge abutment terminating in the floodplain of a compound channel. The study's purpose was to improve current techniques of abutment scour prediction, which are based primarily on laboratory studies in rectangular channels. It is indicated that a discharge contraction ratio arising from a theoretical contraction scour analysis for equilibrium conditions can be used for explaining the effect of flow distribution on the local abutment scour depth in the case where significant backwater occurs from bridge contraction. The use of reference values of approach flow depth and velocity in the floodplain for undisturbed conditions without the bridge is shown to collapse experimental results for scour depth in both the case of a contraction with negligible backwater, and the case of a contraction with significant backwater in the bridge approach section.

Evaluation of GMDH networks for prediction of local scour depth at bridge abutments in coarse sediments with thinly armored beds

2015 ◽  
Vol 104 ◽  
pp. 387-396 ◽  
Author(s):  
Mohammad Najafzadeh ◽  
Gholam-Abbas Barani ◽  
Masoud-Reza Hessami-Kermani
Keyword(s):  
Local Scour ◽  
Scour Depth ◽  
Bridge Abutments ◽  
Coarse Sediments
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