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.

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.

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.

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.

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.

scholarly journals Local scour at vertical-wall abutments under clear-water flow conditions

2006 ◽  
Vol 42 (10) ◽  
Author(s):  
Cristina Maria Sena Fael ◽  
Gonzalo Simarro-Grande ◽  
Juan-Pedro Martín-Vide ◽  
António Heleno Cardoso
Keyword(s):  
Water Flow ◽  
Vertical Wall ◽  
Local Scour ◽  
Clear Water ◽  
Flow Conditions

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.

scholarly journals Bridge Abutment Protection against Scouring for Unsteady Flow Conditions

2021 ◽  
Author(s):  
Maryam Khajavi ◽  
Seyed Mahmood Kashefipour ◽  
Mahmood Shafai Bejestan
Keyword(s):  
Unsteady Flow ◽  
Steady Flow ◽  
Clear Water ◽  
Flow Conditions ◽  
Spur Dike ◽  
Base Time ◽  
Bridge Abutment ◽  
Water Conditions ◽  
Scouring Process ◽  
Spur Dikes

The bridge abutment is one of the main parts of a bridge and significantly contributes to bridge stability. This study experimentally investigated the effect of the unsteadiness characteristics of hydrographs on the scouring phenomenon around the bridge abutment under clear water conditions. The ability of the permeable and impermeable spur dikes and their distances from the abutment at its upstream on the control of scouring around the bridge abutment was also investigated. The experimental observations imply that the effect of unsteady flow on the scouring process is relatively similar to the steady flow conditions. The results showed that the base time of hydrographs, the type of spur dikes, and the distance of spur dikes from the bridge abutment were the dominant parameters among the considered parameters in this study on the scouring process around the abutment. The results also revealed that the impermeable spur dike was able to completely eliminate scouring around the bridge abutment for two distances of 2L and 3L (where L is the abutment length) for both steady and unsteady flow conditions.

Experimental study of clear-water contraction scour

2020 ◽  
Vol 20 (3) ◽  
pp. 943-952 ◽  
Author(s):  
Ravindra Kumar Singh ◽  
Manish Pandey ◽  
Jaan H. Pu ◽  
Srinivas Pasupuleti ◽  
Vasanta G. Kumar Villuri
Keyword(s):  
Experimental Study ◽  
Reasonable Agreement ◽  
Time Dependent ◽  
Scour Depth ◽  
Clear Water ◽  
Equilibrium Conditions ◽  
Bridge Abutment ◽  
Water Conditions ◽  
Contraction Scour ◽  
Equilibrium Scour Depth

Abstract In this paper, experimental results of clear-water scour on a sand bed under short contractions were studied. Sequences of test runs were performed under clear-water conditions for three different contraction ratios. The outcomes of the experiments were employed to define the effects of various parameters on equilibrium scour depth under clear-water scour conditions. In this work, the precision of three maximum scour depth equations was tested from previous studies for contraction scour cases. Two new analytical equations were proposed to calculate time-dependent scour depth and maximum scour at equilibrium conditions, respectively, from the study. The proposed equations were validated using measurements from the present study as well as from previous literature, and the equations show a reasonable agreement between measured and computed values of scour depth under clear-water conditions in short contraction. The presented equations can be used for studying protection of the submerged portion at a bridge abutment or any similar structure.

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 Simultaneous Effect of Collar and Roughness on Reducing and Controlling the Local Scour around Bridge Abutment

2017 ◽  
Vol 65 (2) ◽  
pp. 491-499
Author(s):  
Hamed Shahsavari ◽  
Manouchehr Heidarpour ◽  
Mohammad Mohammadalizadeh
Keyword(s):  
Local Scour ◽  
Hydraulic Structures ◽  
Scour Depth ◽  
River Engineering ◽  
Crucial Importance ◽  
Clear Water ◽  
Simultaneous Effect ◽  
Bridge Abutment ◽  
Scouring Process ◽  
Local Roughness

Investigation of local scour around hydraulic structures particularly bridges is of crucial importance in river engineering. Bridge destruction mostly occurs as a result of scour phenomenon around piers and abutments, not because of structural weaknesses. Hence, finding a solution to reduce scour depth is momentous. In this study which was conducted in the conditions of clear water scour, the effect of local roughness and collar and also impact of using them simultaneously around bridge abutment were evaluated. The results demonstrated that the existence of roughness causes a reduction in the severity of scouring process and its final depth and the use of collar leads to a delay in the scouring process in addition to the ultimate reduction in the scour depth, which in case of using them simultaneously, scour depth decreases by about 83%.

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