A Study on Interaction between Overfall Types and Scour at Bridge Piers with a Moving-Bed Experiment

River slopes can be changed due to an extreme event, e.g., a large-scale earthquake. This can uplift a riverbed greatly and thereby change the behavior of the river flow into a free or submerged overfall. Corresponding damage, including extreme erosion, on bridge piers located in the river can take place due to the aforementioned flow conditions. A reconstructed bridge pier in the same location would also experience a similar impact if the flow condition is not changed. It is important to identify these phenomena and research the mechanism in the interaction between overfall types and scour at bridge piers. Therefore, this paper is aimed at studying a mechanism of free and submerged overfall flow impacts on bridge piers with different distances by a series of moving-bed experiments. The experiment results showed clearly that bridge pier protection requires attention particularly when the pier is located in the maximum scour hole induced by the submerged overfall due to the z directional flow eddies. In many other cases, such as when the location of the bridge pier was at the upstream slope of a scour hole induced by a flow drop, a deposition mound could be observed at the back of the pier. This indicates that, while a pier is at this location, an additional protection takes place on the bridge pier.

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Experimental Characterization of the Flow Field around Oblong Bridge Piers

Fluids ◽

10.3390/fluids6110370 ◽

2021 ◽

Vol 6 (11) ◽

pp. 370

Author(s):

Ana Margarida Bento ◽

Teresa Viseu ◽

João Pedro Pêgo ◽

Lúcia Couto

Keyword(s):

Flow Field ◽

Large Scale ◽

Bridge Pier ◽

Bridge Piers ◽

Shear Stresses ◽

Velocity Measurements ◽

Bridge Foundations ◽

Scour Hole ◽

Movable Bed

The prediction of scour evolution at bridge foundations is of utmost importance for engineering design and infrastructures’ safety. The complexity of the scouring inherent flow field is the result of separation and generation of multiple vortices and further magnified due to the dynamic interaction between the flow and the movable bed throughout the development of a scour hole. In experimental environments, the current approaches for scour characterization rely mainly on measurements of the evolution of movable beds rather than on flow field characterization. This paper investigates the turbulent flow field around oblong bridge pier models in a well-controlled laboratory environment, for understanding the mechanisms of flow responsible for current-induced scour. This study was based on an experimental campaign planned for velocity measurements of the flow around oblong bridge pier models, of different widths, carried out in a large-scale tilting flume. Measurements of stream-wise, cross-wise and vertical velocity distributions, as well as of the Reynolds shear stresses, were performed at both the flat and eroded bed stages of scouring development with a high-resolution acoustic velocimeter. The time-averaged values of velocity and shear stress are larger in the presence of a developed scour hole than in the corresponding flat bed configuration.

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A Hooked-Collar for Bridge Piers Protection: Flow Fields and Scour

Water ◽

10.3390/w10091251 ◽

2018 ◽

Vol 10 (9) ◽

pp. 1251 ◽

Cited By ~ 10

Author(s):

Su-Chin Chen ◽

Samkele Tfwala ◽

Tsung-Yuan Wu ◽

Hsun-Chuan Chan ◽

Hsien-Ter Chou

Keyword(s):

Laboratory Experiments ◽

Horseshoe Vortex ◽

Flow Fields ◽

Bridge Pier ◽

The Other ◽

Bridge Piers ◽

Vortex Strength ◽

Numerical Tests ◽

Scour Hole ◽

New Type

A new type of collar, the hooked-collar, was studied through experiments and numerical methods. Tests were conducted using a hooked collar of a width of 1.25b and a height of 0.25b, where b is the bridge-pier width. The hooked-collar efficiency was evaluated by testing different hooked-collar placements within the bridge-pier, which were compared to the bridge-pier without any collar. A double hooked-collar configuration, one placed at the bed level and the other buried 0.25b, was the most efficient at reducing the scour hole. In other cases, a hooked-collar positioned 0.25b above the bed slightly reduced the scour hole and had similar scour patterns when compared to the pier without the hooked-collar. The flow fields along the vertical symmetrical plane in the experiments are also presented. Laboratory experiments and numerical tests show that maximal downflow is highly reduced along with a corresponding decrease in horseshoe vortex strength for the experiments with the hooked-collar, compared to cases without the hooked-collar. The flow fields reveal that the maximum turbulent kinetic energy decreases with the installation of the hooked-collar.

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

Water ◽

10.3390/w12113192 ◽

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.

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

Water ◽

10.3390/w11122458 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2458 ◽

Cited By ~ 7

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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Seismic performance of a bridge pier reinforced with titanium alloy bars

IABSE Congress, Christchurch 2021: Resilient technologies for sustainable infrastructure ◽

10.2749/christchurch.2021.0133 ◽

2021 ◽

Author(s):

Mahesh Acharya ◽

Mustafa Mashal ◽

Jared Cantrell

Keyword(s):

Titanium Alloy ◽

Cyclic Loading ◽

Seismic Performance ◽

Large Scale ◽

Plastic Hinge ◽

Bridge Pier ◽

Bridge Piers ◽

Structural Performance ◽

Concrete Bridge ◽

Hinge Zone

<p>The research in this paper focuses on the use of Titanium Alloy Bars (TiABs) in concrete bridge piers located in high seismic zones. The paper discusses a new bridge pier system that incorporates both seismic resiliency and durability concepts. A large-scale bridge pier, reinforced with TiABs and spiral, is tested under quasi-static cyclic loading protocol. The results are compared against a benchmark cast-in-place pier with normal rebars and spiral under the same loading protocol. Based on the testing results, the use of TiABs in concrete piers would reduce rebar congestion up to 50%, provide adequate ductility, and would result in reduced residual displacement following an earthquake. The pier reinforced with TiABs reached higher drift ratios compared to cast-in-place pier. Furthermore, smaller flexural cracks that are likely to appear in the plastic hinge zone during moderate earthquakes are not a major concern for structural performance and durability of bridge piers reinforced with TiABs.</p>

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Impact of armour layer on the depth of scour hole around side-by-side bridge piers under ice-covered flow condition

Journal of Hydrology and Hydromechanics ◽

10.2478/johh-2019-0010 ◽

2019 ◽

Vol 67 (3) ◽

pp. 240-251

Author(s):

Mohammad Reza Namaee ◽

Jueyi Sui

Keyword(s):

Grain Size ◽

Froude Number ◽

Large Scale ◽

Bridge Piers ◽

Scour Depth ◽

Flow Conditions ◽

Densimetric Froude Number ◽

Open Flow ◽

Scour Holes ◽

The Impact

Abstract In the present study, experiments were conducted in a large-scale flume to investigate the issue of local scour around side-by-side bridge piers under both ice-covered and open flow conditions. Three non-uniform sediments were used in this experimental study. Analysis of armour layer in the scour holes around bridge piers was performed to inspect the grain size distribution curves and to study the impact of armour layer on scour depth. Assessments of grain size of deposition ridges at the downstream side of bridge piers have been conducted. Based on data collected in 108 experiments, the independent variables associated with maximum scour depth were assessed. Results indicate that the densi-metric Froude number was the most influential parameter on the maximum scour depth. With the increase in grain size of the armour layer, ice cover roughness and the densimetric Froude number, the maximum scour depth around bridge piers increases correspondingly. Equations have been developed to determine the maximum scour depth around bridge piers under both open flow and ice covered conditions.

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

Journal of Hydrology and Hydromechanics ◽

10.2478/johh-2021-0014 ◽

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.

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Non-Intrusive Underwater Measurement of Local Scour Around a Bridge Pier

Water ◽

10.3390/w11102063 ◽

2019 ◽

Vol 11 (10) ◽

pp. 2063 ◽

Cited By ~ 1

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.

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

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b2000.078219 ◽

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.

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Sources of Chlorophenolic Compounds to the Fraser River Estuary

Water Quality Research Journal ◽

10.2166/wqrj.1988.005 ◽

1988 ◽

Vol 23 (1) ◽

pp. 55-68 ◽

Cited By ~ 12

Author(s):

J. H. Carey ◽

J. H. Hart

Keyword(s):

River Flow ◽

River Estuary ◽

Low Flow ◽

Fraser River ◽

Pulp Mills ◽

Flow Conditions ◽

Downstream Site ◽

Upstream Site ◽

The North ◽

Main River

Abstract The identity and concentrations of chlorophenolic compounds in the Fraser River estuary were determined under conditions of high and low river flow at three sites: a site upstream from the trifurcation and at downstream sites for each main river arm. Major chlorophenolics present under both flow regimes were 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), pentachlorophenol (PCP), tetrachloroguaiacol (TeCG) and a compound tentatively identified as 3,4,5-trichloroguaiacol (3,4,5-TCG). Under high flow conditions, concentrations of the guaiacols were higher than any of the Chlorophenols and concentrations of all five chlorophenolics appeared to correlate. Under low flow conditions, concentrations of chloroguaiacols were higher than Chlorophenols at the upstream site and at the downstream site on the Main Arm, whereas at the downstream site on the North Arm, concentrations of 2,3,4,6-TeCP and PCP were higher than the chloroguaiacols in some samples. Overall, the results indicate that pulp mills upstream from the estuary are important sources of chlorophenolics to the estuary under all flow conditions. Additional episodic inputs of 2,3,4,6-TeCP and PCP from lumber mills occur along the North Arm. When these inputs occur, they can cause the concentrations of Chlorophenols in the North Arm to exceed provisional objectives. If chloroguaiacols are included as part of the objective, concentrations of total chlorophenolics in water entering the estuary can approach and exceed these objectives, especially under low flow conditions.

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