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 Effect of Soil Non-Uniformity on Scour For Circular Compound Bridge Piers

2019 ◽  
Vol 8 (2) ◽  
pp. 2051-2059
Keyword(s):  
Experimental Investigation ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Flowing Water ◽  
Railway Bridges ◽  
The Past ◽  
Economical Design ◽  
Circular Compound ◽  
Bridge Failure

Bridge piers having a varying foundation diameter are known as compound bridge piers. In India for the construction of road and railway bridges circular compound bridge piers are mostly adopted. In past studies it has been concluded that 60-70% of bridge failure occurs because of scour around bridge pier across a river due to flowing water. Most of the past studies were done on the uniform bridge pier and a very few studies has been carried out so far on scour around compound bridge piers. For economical design of bridge pier foundation there is a need to determine the scour depth. In the present study, an experimental investigation has been carried out for computation of time variant change of scour depth for two different models of circular compound bridge piers over non-uniform soil for all possible cases of position of footing with respect to level of the bed, i.e., I. Footing at the level of bed, and II. Footing below the level of bed (1cm, 2cm, 3cm and 4cm) for non-uniform sediments

Reduction of local scour around a bridge pier by using different shapes of pier slots and collars

2020 ◽  
Vol 20 (3) ◽  
pp. 1006-1015 ◽  
Author(s):  
A. Bestawy ◽  
T. Eltahawy ◽  
A. Alsaluli ◽  
A. Almaliki ◽  
M. Alqurashi
Keyword(s):  
Three Dimensional ◽  
Laser Scanner ◽  
Local Scour ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Contour Maps ◽  
Reduction Methods ◽  
Analysis System ◽  
Bridge Failure

Abstract Local scour around bridge piers is one of the main causes of bridge failure all over the world. Experimental and hydraulic models were carried out to investigate two types of scour reduction methods around a single cylindrical pier, namely the pier's slots and collars. The efficiency of various types of pier slots and circular collars around the pier's base in reducing scour were studied. A new shape of a conical collar was developed by the authors and examined along with other shapes. The results revealed that collars, in general, have more influence in reducing scour depth than slots made in the front and rear of bridge piers. The sigma-slot acts better than other tested slots, with a reduction in the scour depths of 59.3% and 52.8% at the upstream and downstream of the pier, respectively. On the other hand, the conical collar appeared to be the most effective collar shape in reducing the scour around the bridge pier, with a 61.1% reduction in the scour depth downstream of the pier. A three-dimensional laser scanner was used to capture the bed topography at the end of each experiment and contour maps of the deformed bed were produced. A one-dimensional Hydrologic Engineering Center-River Analysis System model was developed with a single bridge pier to predict the scour depth around the pier in an attempt to introduce new values for the pier nose shape factor, , which describes the tested piers.

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 Optimum Design for Controlling the Scouring on Bridge Piers

2019 ◽  
Vol 5 (9) ◽  
pp. 1904-1916 ◽  
Author(s):  
Abdul-Hassan K. Al-Shukur ◽  
Manar Hussein Ali
Keyword(s):  
Experimental Investigation ◽  
Optimum Design ◽  
Bridge Pier ◽  
Physical Models ◽  
Bridge Piers ◽  
Optimum Shape ◽  
Scour Depth ◽  
Bridge Failure

The scouring around bridge pier can be considered the most important reasons of bridge failure. Therefore, we investigated by using physical models of piers and we used single pier with square collar , circular collar and interaction of two piers   in laboratory channel, its width 1 m and applied three velocities (0.1, 0.08, and 0.07) m/sec. This experimental investigation was made to choose the optimum shape and location of collar of single pier and comparing it with the interaction of two piers, the results showed that both square and circular collar decrease the scour depth, but the square collar is more effective of reducing scouring and the best location at bed level for single pier, comparing the results of single pier with the interaction of two piers, the interaction of two piers without any countermeasure reduced scour depth about 58%. 

scholarly journals Effect of Angle between Pier and Center of River Flow on Local Scouring around the Bridge Pier

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3192
Author(s):  
Takuma Kadono ◽  
Shinichiro Okazaki ◽  
Yoshihiro Kabeyama ◽  
Toshinori Matsui
Keyword(s):  
Water Flow ◽  
Heavy Rainfall ◽  
River Flow ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Flowing Water ◽  
River Flows ◽  
Scouring Depth

In recent years, heavy rainfall disasters have caused frequent damage to bridge piers due to scouring and have resulted in the fall of bridges in many areas in Japan. The objective of this study was to investigate the effect of local scouring around the downstream of the piers on the local scouring around the center of the river flowing at an angle to the piers. It was found that when the center of the river flows at an angle to the piers, the scouring area becomes wider from the upstream to the downstream of the piers because of the longer inhibition width of the piers positioned perpendicular to the water flow. The downstream scouring depth tends to be smaller than the upstream scouring depth. In addition, the time to the onset of tilting deformation of the piers increases with the inhibition width of the piers positioned perpendicular to the flowing water.

Assessing energetic flow structures responsible for bridge pier scour

2020 ◽  
Author(s):  
Yi Xu ◽  
Manousos Valyrakis ◽  
Panagiotis Michalis
Keyword(s):  
Bridge Pier ◽  
Bridge Piers ◽  
Flow Structures ◽  
Scour Depth ◽  
Dynamical Process ◽  
Bridge Scour ◽  
Earth Surface ◽  
Mean Flow ◽  
Geophysical Research ◽  
Hydraulic Infrastructure

<p>Scour has been recognized as one of the primary reasons for bridge pier destabilization. As extreme weather intensifies and hydraulic infrastructure such as bridge piers and abutments (many constructed since the Victorian era, for the case of the UK) continues to age, the challenge of scour-induced hazards will keep growing impacting the resilience of our society. Thus, there is an increasing value in studying the highly dynamical process of scour around hydraulic infrastructure. Maximum scour depth estimation has been broadly studied by researchers over the past decades, using phenomenological or empirical approaches, linking mean flow properties, bridge pier and riverbed materials characteristics [1, 2].</p><p>This study aims to get a better understanding of how the turbulent flow field modified by the bridge pier, interacts with the bed surface towards the generation of the scour hole. This is pursued by following a dynamical approach via assessing the flow structures that are sufficiently energetic [3] to remove bed material from the vicinity of the bridge pier.</p><p>A series of scour experiments with different lengthscale of model bridge piers is conducted in a water recirculating research flume. For each of these cases flow velocity profiles are collected downstream the bridge pier using high resolution acoustic Doppler velocimetry (ADV). Using the raw data collected near the bed surface and information for the bed surface material, the criterion of impulse [4] is used as a metric for assessing the extend and maximum scour depth. The results are compared for the different measurement locations are compared to better understand the process of scour downstream different model piers.</p><p>[1]. M Valyrakis, P Michalis, H Zhang, (2015). A new system for bridge scour monitoring and prediction, Proceedings of the 36th IAHR World Congress, 1-4.</p><p>[2]. Yagci, O., Celik, M. F., Kitsikoudis, V., Ozgur Kirca, V.S., Hodoglu, C., Valyrakis, M. , Duran, Z. and Kaya, S. (2016) Scour patterns around isolated vegetation elements. Advances in Water Resources, 97, pp. 251-265.(doi:10.1016/j.advwatres.2016.10.002)</p><p>[3]. Valyrakis, M. , Diplas, P. and Dancey, C.L. (2013) Entrainment of coarse particles in turbulent flows: an energy approach. Journal of Geophysical Research: Earth Surface, 118(1), pp. 42-53. (doi:10.1029/2012JF002354)</p><p>[4]. Valyrakis, M. , Diplas, P., Dancey, C.L., Greer, K. and Celik, A.O. (2010) Role of instantaneous force magnitude and duration on particle entrainment. Journal of Geophysical Research: Earth Surface, 115(F02006), 18p. (doi:10.1029/2008JF001247)</p>

Development of an Analysis Methodology for Pressure Flow Scour Under Flooded Bridge Decks Using Commercial CFD Software

2010 ◽  
Author(s):  
Dipankar Biswas ◽  
Steven A. Lottes ◽  
Pradip Majumdar ◽  
Milivoje Kostic
Keyword(s):  
Shear Stress ◽  
Turbulence Model ◽  
Critical Shear Stress ◽  
Scour Depth ◽  
Bed Shear Stress ◽  
Cfd Analysis ◽  
Flow Conditions ◽  
Pressure Flow ◽  
Scour Hole ◽  
Bridge Failure

Bridges are a significant component of the ground transportation infrastructure in the United States. With about sixty percent of bridge failures due to hydraulic causes, primarily scour, application of computational fluid dynamics (CFD) analysis techniques to the assessment of risk of bridge failure under flood conditions can provide increased accuracy in scour risk assessment at a relatively low cost. The analysis can be used to make optimum use of limited federal and state funds available to maintain and replace bridges and ensure public safety while traveling on the nation’s roads and highways during and after floods. Scour is the erosion of riverbed material during high flow conditions, such as floods. When scouring of the supporting soil around the piers and abutments of bridges takes place, risk of bridge failure increases. A simulation methodology to conservatively predict equilibrium shape and size of the scour hole under pressure flow conditions for flooded bridge decks using commercial CFD software was developed. The computational methodology has been developed using C++ to compute changes in the bed contour outside of the CFD software and generate a re-meshing script to change the bed boundary contour. STAR-CD was used to run the hydrodynamic analysis to obtain bed shear stress, and a BASH script was developed to automate cycling between computing bed shear stress with the CFD software and computing changes in the bed contour due to scour predicted using the computed shear stress for the current bed contour. A single-phase moving boundary formulation has been developed to compute the equilibrium scour hole contour that proceeds through a series of quasi-steady CFD computations. It is based on CFD analysis of the flow fields around the flooded bridge deck and shear stress computed at the bed modeled as a rough wall. A high Reynolds number k-ε turbulence model with standard wall functions, based on a Reynolds-Averaged Navier-Stokes (RANS) turbulence model, was used to compute bed shear stress. The scour sites on the bed were identified as those sites where the computed shear stress exceeded the critical shear stress computed from a published correlation for flat bed conditions. Comparison with experimental data obtained from the Turner-Fairbank Highway Research Center (TFHRC), McLean, VA, USA, revealed larger discrepancies than anticipated between the bridge inundation ratio and the scour hole depth. Although scour hole slopes were small for the cases tested, a correction to critical shear stress to account for bed slope was also tested. It did not significantly improve the correlation between CFD prediction and experimental observations. These results may be a consequence of using only excess shear stress above critical as a criteria for scour when other physical mechanisms also contribute to the initiation of scour. Prediction of scour depth using federal guidelines over predicts scour depth by as much as an order of magnitude in some cases. Over prediction is acceptable for purposes of ensuring bridge safety. CFD methods for scour prediction can be a significant improvement of current methods as long as under prediction of scour depth is avoided. Conservative scour prediction using CFD methods can be achieved by using conservative values of parameters such as critical shear stress and effective bed roughness.

scholarly journals Scaling of Scour Depth at Bridge Pier Based on Characteristic Dimension of Large-Scale Vortex

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2458 ◽  
Author(s):  
Nian-Sheng Cheng ◽  
Maoxing Wei
Keyword(s):  
Large Scale ◽  
Horseshoe Vortex ◽  
Bridge Pier ◽  
Theoretical Formula ◽  
Scour Depth ◽  
Flow Depth ◽  
Flow Conditions ◽  
Hydraulic Radius ◽  
Vortex System ◽  
Large Scale Vortex

By examining the variations in the dimensions of a horseshoe vortex system in front of a pier, the present study proposes a new length scale, called pier hydraulic radius, for the scaling of the maximum scour depth at a bridge pier. It is shown that, in comparison with other length scales, the pier hydraulic radius is more effective for quantifying combined effects of pier width and flow depth on the local scour for both low and high flow conditions. A theoretical formula is finally derived, which agrees well with experimental data reported in the literature.

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