scholarly journals Effect of debris accumulation on scour evolution at bridge pier in bank proximity

2021 ◽  
Vol 69 (1) ◽  
pp. 108-118
Author(s):  
Michele Palermo ◽  
Simone Pagliara ◽  
Deep Roy
Keyword(s):  
Bridge Piers ◽  
Scour Depth ◽  
Structural Failure ◽  
Clear Water ◽  
River Bank ◽  
Debris Accumulation ◽  
Equilibrium Morphology ◽  
Satisfactory Prediction ◽  
Prediction Capability ◽  
Water Depths

AbstractLarge debris transported by flood affects scour features at bridge piers and increases the risks of structural failure. Geometric characteristics of the debris and the relative position of the pier with respect to the river bank are important parameters for the scour process. The interaction between the water flow and debris accumulation increases the shear stress, turbulence and consequently enhances the scour depth at the pier. This paper aims at analyzing such effects on scour evolution at bridge piers. To this end, two series of tests were carried out under clear water condition with different debris geometries and percentage blockage ratios. Experimental evidences showed that the pier position only influences scour evolution and equilibrium morphology for low water depths. Conversely, its effect becomes negligible for scour at bridge piers with debris accumulation and higher water depths. Useful practical relationships have been derived, with satisfactory prediction capability of the scour evolution for all the tested configurations.

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.

Local scour at piled bridge piers including an examination of the superposition method

2014 ◽  
Vol 41 (5) ◽  
pp. 461-471 ◽  
Author(s):  
Ata Amini ◽  
Bruce W. Melville ◽  
Thamer M. Ali
Keyword(s):  
Bridge Piers ◽  
Prediction Methods ◽  
Scour Depth ◽  
Superposition Method ◽  
Clear Water ◽  
Laboratory Flume ◽  
Pile Cap ◽  
The Individual ◽  
Comparison Of The Results ◽  
Bed Material

An experimental investigation of clear water scour at complex piers is presented. Five complex piers, comprising different configurations of piles, pile cap, and column, were tested in a laboratory flume using uniform bed material. The piers were tested for a range of possible elevations relative to the streambed elevation. Experiments were undertaken using the complex piers and also using the individual components of each complex pier. A comparison of the results for the intact piers and for their components enabled an evaluation of the prediction methods involving superposition of scour depths at piles, pile cap, and pier column. The superposition method is found to give inadequate estimates of total scour depth in many cases.

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.

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.

scholarly journals Prediction of maximum scour depth around piers with debris accumulation using EPR, MT, and GEP models

2016 ◽  
Vol 18 (5) ◽  
pp. 867-884 ◽  
Author(s):  
Mohammad Najafzadeh ◽  
Mohammad Rezaie Balf ◽  
Esmat Rashedi
Keyword(s):  
Polynomial Regression ◽  
Gene Expression Programming ◽  
Laboratory Data ◽  
Experimental Studies ◽  
Local Scour ◽  
Bridge Piers ◽  
Scour Depth ◽  
Effective Parameters ◽  
Pier Scour ◽  
Debris Accumulation

Pier scour phenomena in the presence of debris accumulation have attracted the attention of engineers to present a precise prediction of the local scour depth. Most experimental studies of pier scour depth with debris accumulation have been performed to find an accurate formula to predict the local scour depth. However, an empirical equation with appropriate capacity of validation is not available to evaluate the local scour depth. In this way, gene-expression programming (GEP), evolutionary polynomial regression (EPR), and model tree (MT) based formulations are used to develop to predict the scour depth around bridge piers with debris effects. Laboratory data sets utilized to perform models are collected from different literature. Effective parameters on the local scour depth include geometric characterizations of bridge piers and debris, physical properties of bed sediment, and approaching flow characteristics. The efficiency of the training stages for the GEP, MT, and EPR models are investigated. Performances of the testing results for these models are compared with the traditional approaches based on regression methods. The uncertainty prediction of the MT was quantified and compared with those of existing models. Also, sensitivity analysis was performed to assign effective parameters on the scour depth prediction.

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.

scholarly journals Prediction of local scour depth at bridge piers under clear-water and live-bed conditions: comparison of literature formulae and artificial neural networks

2011 ◽  
Vol 13 (4) ◽  
pp. 812-824 ◽  
Author(s):  
E. Toth ◽  
L. Brandimarte
Keyword(s):  
Neural Networks ◽  
Sediment Transport ◽  
Field Data ◽  
Local Scour ◽  
Bridge Piers ◽  
Validation Dataset ◽  
Scour Depth ◽  
Clear Water ◽  
Transport Mode ◽  
Artificial Neural

The scouring effect of the flowing water around bridge piers may undermine the stability of the structure, leading to extremely high direct and indirect costs and, in extreme cases, the loss of human lives. The use of Artificial Neural Network (ANN) models has been recently proposed in the literature for estimating the maximum scour depth around bridge piers: this study aims at further investigating the potentiality of the ANN approach and, in particular, at analysing the influence of the experimental setting (laboratory or field data) and of the sediment transport mode (clear water or live bed) on the prediction performances. A large database of both field and laboratory observations has been collected from the literature for predicting the maximum local scour depth as a function of a parsimonious set of variables characterizing the flow, the sediments and the pier. Neural networks with an increasing degree of specialization have been implemented – using different subsets of the calibration data in the training phase – and validated over an external validation dataset. The results confirm that the ANN scour depths' predictions outperform the estimates obtained by empirical formulae conventionally used in the literature and in the current engineering practice, and demonstrate the importance of taking into account the differences in the type of available data – laboratory or field data – and the sediment transport mode – clear water or live bed conditions.

scholarly journals A method for evaluating local scour depth at bridge piers due to debris accumulation

2020 ◽  
Vol 173 (2) ◽  
pp. 86-99 ◽  
Author(s):  
Mohsen Ebrahimi ◽  
Slobodan Djordjević ◽  
Diego Panici ◽  
Gavin Tabor ◽  
Prakash Kripakaran
Keyword(s):  
Local Scour ◽  
Bridge Piers ◽  
Scour Depth ◽  
Debris Accumulation

scholarly journals Experimental Study of Inclined Bridge Pier Scouring

2020 ◽  
Vol 39 (4) ◽  
pp. 859-870
Author(s):  
Fakhar Muhammad Abbas ◽  
Usman Ali Naeem ◽  
Usman Ghani ◽  
Amina Khan ◽  
Talat Farid Ahmad
Keyword(s):  
Experimental Study ◽  
Inverse Relationship ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Clear Water ◽  
Lower Strength ◽  
Flow Rates ◽  
Laboratory Flume ◽  
Horseshoe Vortices

The bridges are one of important structures in any country. The failure of bridges occurs due to many factors including design flaws and manufacturing construction errors. Among all imperfections scouring around the pier is the most detrimental. So, the estimation of local scouring around a bridge pier is of fundamental importance for the safe design of bridges. Although numerous researches have been done on local scouring around a single bridge pier. The present study investigates the effect of angle of inclination of dual bridge pier configuration on local scouring around bridge piers. Principally rectangular shaped dual bridge piers were installed in sand bed of laboratory flume at angle of inclination of 0°,7°,12°,15° and 19° with vertical respectively. Three different flow rates 9, 14 and 18L/sec were considered during each trial. The duration of each trial was kept around 2 hours. The scour depth was measured separately around both piers with the help of point gauge under clear water condition. The value of scour depth around upstream pier was larger as compared to downstream pier because of the lower strength of horseshoe vortices around downstream pier. From the experimental results, it can be concluded that there is an inverse relationship between the angle of inclination and scour depth, an increase in the angle of inclination leads to decrease in scour depth around both piers. The value of scour depth was maximum when piers were at 0° and minimum at 19°. It was also found that scour depth increases with the increase in flow rate.

scholarly journals Application of gradient tree boosting regressor for the prediction of scour depth around bridge piers

2021 ◽  
Author(s):  
B. M. Sreedhara ◽  
Amit Prakash Patil ◽  
Jagalingam Pushparaj ◽  
Geetha Kuntoji ◽  
Sujay Raghavendra Naganna
Keyword(s):  
Model Performance ◽  
Bridge Piers ◽  
Machine Learning Techniques ◽  
Group Method ◽  
Scour Depth ◽  
Clear Water ◽  
Sediment Size ◽  
Learning Techniques ◽  
Scour Hazard ◽  
Bed Scour

Abstract Scour around bridge piers is a complex phenomenon and it is essential to assess or predict the scour hazard around bridge piers in tandem with completely understanding its mechanism. To date, there is no exact method for the estimation of scour depth. Nowadays, machine learning techniques are being recognized as effective tools for the prediction of scour depth using experimental data. In the present study, gradient tree boosting (GTB) technique was used for the prediction of scour depth around various pier shapes under different streambed conditions. Sediment size, sediment quantity, velocity, and flow time were used as input parameters to predict the scour depth under clear-water and live-bed scour conditions. The scour depth was predicted for different pier shapes such as, circular, rectangular, round-nosed and sharp-nosed shaped. The GTB model predicted scour depth values were compared with that of the group method of data handling (GMDH) technique. The performance of GTB and GMDH models were then evaluated based on statistical indices such as RRMSE, NNSE, WI, MNE, SI, and KGE. The study concludes that the GTB model performance was relatively superior to that of GMDH in the prediction of scour depth around different pier shapes.

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