scholarly journals Experimental study for determination of collar dimensions around bridge pier

2015 ◽  
Vol 10 (1) ◽  
pp. 89-96
Author(s):  
Afshin Jahangirzadeh ◽  
Shatirah Akib
Keyword(s):  
Experimental Study ◽  
Temporal Trend ◽  
Bridge Pier ◽  
Scour Depth ◽  
Scour Hole ◽  
Scour Countermeasure ◽  
Reduction Percentage ◽  
Shape And Size

The shape and size of a collar is important to maximize its effect as a scour countermeasure. Current research shows that the depth of the scour hole is decreased by using rectangular collars around circular piers. This study determined the approximate optimum dimensions for rectangular collars to minimize the temporal trend of scouring around a pier model. Effects of different sizes of rectangular collars on a model pier were investigated both at the upstream and downstream of the flume. It was observed that irrespective of the rectangular collar dimensions the upstream and the downstream were estimated to be 0.86 and 1.42, respectively. The optimum collar width was estimated to be 2.8 times the diameter of the pier. By using this optimized collar dimension, the non-dimensional depth of scour reached a min value of 0.034 at 72 h. The reduction percentage of the scour depth reached 98% at 72 h.

scholarly journals Open Channel Sluice Gate Scouring Parameters Prediction: Different Scenarios of Dimensional and Non-Dimensional Input Parameters

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 353 ◽  
Author(s):  
Ali Yousif ◽  
Sadeq Sulaiman ◽  
Lamine Diop ◽  
Mohammad Ehteram ◽  
Shamsuddin Shahid ◽  
...  
Keyword(s):  
Scour Depth ◽  
Sluice Gate ◽  
Analysis Technique ◽  
Dimensionless Groups ◽  
Scour Hole ◽  
Adaptive Regression ◽  
Learning Machine ◽  
Bed Material ◽  
Statistical Metrics

The determination of scour characteristics in the downstream of sluice gate is highly important for designing and protection of hydraulic structure. The applicability of modern data-intelligence technique known as extreme learning machine (ELM) to simulate scour characteristics has been examined in this study. Three major characteristics of scour hole in the downstream of a sluice gate, namely the length of scour hole (Ls), the maximum scour depth (Ds), and the position of maximum scour depth (Lsm), are modeled using different properties of the flow and bed material. The obtained results using ELM were compared with multivariate adaptive regression spline (MARS). The dimensional analysis technique was used to reduce the number of input variable to a smaller number of dimensionless groups and both the dimensional and non-dimensional variables were used to model the scour characteristics. The prediction performances of the developed models were examined using several statistical metrics. The results revealed that ELM can predict scour properties with much higher accuracy compared to MARS. The errors in prediction can be reduced in the range of 79%–81% using ELM models compared to MARS models. Better performance of the models was observed when dimensional variables were used as input. The result indicates that the use of ELM with non-dimensional data can provide high accuracy in modeling complex hydrological problems.

Experimental Study on Effect of Ogival Bridge Pier on Scour Hole Depth

2011 ◽  
Author(s):  
Alireza Masjedi ◽  
B. Zeraat ◽  
M. Hydarnejad ◽  
Jiachun Li ◽  
Song Fu
Keyword(s):  
Experimental Study ◽  
Bridge Pier ◽  
Hole Depth ◽  
Scour Hole

scholarly journals Optimal Octagonal Hooked Collar Countermeasure to Reduce Scour Around a Single Bridge Pier

2020 ◽  
Author(s):  
Rashid Farooq ◽  
Abdul Razzaq Ghumman ◽  
Muhammad Atiq Ur Rehman Tariq ◽  
Afzal Ahmed ◽  
Khan Zaib Jadoon
Keyword(s):  
Cross Section ◽  
Vital Role ◽  
Bridge Pier ◽  
Scour Depth ◽  
Clear Water ◽  
Action Current ◽  
Pier Scour ◽  
Uniform State ◽  
Scour Hole ◽  
New Equation

Pier modification countermeasures are essential as they play a vital role in protecting pier against local scour action. Current study investigates experimentally the scour around vertical pier of octagonal cross section with pier modification such as newly proposed octagonal hooked collar is explored, in steady uniform state, under clear water condition. The results of pier scour without any modification were used as a reference to compute the efficiency of hooked collar provision around octagonal pier. The results show that by increasing the hooked collar width up to 2.5 Wp reduced maximum scour depth significantly. However, the experimental investigation revealed that the best combination to be with a hooked collar width of 2.5 Wp, having sidewall height 0.45 Wp. The best combination minimized around 73.3 % of scour hole depth, compared to octagonal pier without any modification. Using experimental results, a new equation is proposed to predict the scour depth around a bridge pier fitted with hooked collar. Moreover, a relation was developed for maximum scour depth and scour hole volume. Results indicate that the scour hole volume around a bridge pier increases quadratically with maximum scour depth.

Empirical Formulas to Predict the Maximum Scour Depth With ‎Debris Accumulation Around A Single Cylindrical Bridge Pier: An ‎Experimental Study

2020 ◽  
Vol 38 (12A) ◽  
pp. 1790-1800
Author(s):  
Mahmoud S. Al-Khafaji ◽  
Aysar T. Al-Awadi
Keyword(s):  
Experimental Study ◽  
Woody Debris ◽  
Bridge Pier ◽  
Coefficient Of Determination ◽  
Scour Depth ◽  
Empirical Formulas ◽  
Flow Area ◽  
Debris Accumulation ◽  
Modification Factor ◽  
Length Width

The probability of debris accumulation near bridge piers during the heavy storm and river flood convert the ‎hydraulic action of flow and increase the scour depth due to the reduction of flow area and the increase in ‎velocity of flow. In this paper, the effects of debris accumulation length, width and submerged depth on ‎scour depth near bridge pier were investigated. An experimental study for three groups of woody debris ‎accumulation was conducted under clear water condition to investigate the effects on maximum scour depth. ‎The results showed that the increase of blocked area of debris ‎to 27% increases the scour depth by approximately 140%. Furthermore, two empirical exponential formulas was proposed to predict the effect of ‎debris on the maximum scour depth and the modification factor required for single pier. Well agreement ‎was obtained for both derived formulas with coefficient of determination (R2) of 0.96. ‎

scholarly journals Local scour around a bridge pier under ice-jammed flow condition – an experimental study

2021 ◽  
Vol 69 (3) ◽  
pp. 275-287
Author(s):  
Jun Wang ◽  
Zhixing Hou ◽  
Hongjian Sun ◽  
Bihe Fang ◽  
Jueyi Sui ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Local Scour ◽  
Bridge Pier ◽  
Scour Depth ◽  
Flow Conditions ◽  
Hole Depth ◽  
Open Flow ◽  
Ice Jam ◽  
Scour Hole ◽  
Ice Jam Thickness

Abstract The appearance of an ice jam in a river crucially distorts local hydrodynamic conditions including water level, flow velocity, riverbed form and local scour processes. Laboratory experiments are used for the first time here to study ice-induced scour processes near a bridge pier. Results show that with an ice sheet cover the scour hole depth around a bridge is increased by about 10% compared to under equivalent open flow conditions. More dramatically, ice-jammed flows induce both greater scour depths and scour variability, with the maximum scour depth under an ice-jammed flow as much as 200% greater than under equivalent open flow conditions. Under an ice-jammed condition, both the maximum depth and length of scour holes around a bridge pier increase with the flow velocity while the maximum scour hole depth increases with ice-jam thickness. Also, quite naturally, the height of the resulting deposition dune downstream of a scour hole responds to flow velocity and ice jam thickness. Using the laboratory data under ice-jammed conditions, predictive relationships are derived between the flow’s Froude number and both the dimensionless maximum scour depth and the dimensionless maximum scour length.

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 Influence of Scour Development on Turbulent Flow Field in Front of a Bridge Pier

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2370
Author(s):  
Jinzhao Li ◽  
Yilin Yang ◽  
Zhiwen Yang
Keyword(s):  
Flow Field ◽  
Turbulent Flow ◽  
Reynolds Shear Stress ◽  
Bridge Pier ◽  
Scour Depth ◽  
Image Velocimetry ◽  
Scour Hole ◽  
Practical Engineering ◽  
Turbulent Flow Field ◽  
Variation Tendency

This study concerns the turbulent flow field influenced by the scour development around a bridge pier. The scour hole evolution as well as the temporal variation of scour depth around the pier were firstly analyzed. Subsequently, the flow fields in front of the pier at different instants during the scour process were measured using particle image velocimetry (PIV). It shows that the scour depth at the pier front exceeds that of the pier side at the later scouring stage. The temporal development of scour depth can be well predicted by a simple practical engineering model based on an exponential function with a change in the two adjustable coefficients. The flow field indicates that with the development of scour hole, the downward flow in front of the pier becomes more prominent, meanwhile the flow becomes more turbulent. The variation tendency for both velocities and turbulence intensities along the streamwise direction in front the pier shows similarity. The Reynolds shear stress generally increases with developing scour hole, and the region with large value enlarges and moves upstream of the scour hole.

scholarly journals Effects on Scour for Different Foundation Geometry of Compound Circular Bridge Piers

2019 ◽  
Vol 8 (2) ◽  
pp. 2439-2446
Keyword(s):  
Experimental Study ◽  
Rate Of Change ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Flowing Water ◽  
Sound Design ◽  
Flow Conditions ◽  
The Past ◽  
Bridge Failure

This experimental study examines the variation of scour depth with time of Clearwater scour condition around compound circular bridge piers for steady flow conditions. Most of the circular bridge piers are resting on the bigger diameter caissons known as the compound circular bridge piers and are widely used in India for construction of road and railways bridge across the rivers. In past studies, it has been observed that most bridge failure occurs because of scouring due to flowing water around a bridge pier across a river. Most of the past studies were done on the uniform bridge pier and a very few studies have been done so far on scouring around non-uniform bridge piers. Estimation of scour depth is required for the economical and a sound design of bridge pier foundation. In present study, an experimental investigation has been done in a tilting flume for computation of rate of change of depth of scour with time at two different models of compound circular bridge piers by varying the foundation top position with respect to level of bed, i.e., 1. The foundation top at the level of bed, and 2. The foundation top below the level of bed (viz. 10mm, 20mm, 30mm and 40mm) for uniform sediments.

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.

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