Dimensional Analysis As Applied To Scouring Around Bridge Piers In Alluvial Rivers

1983 ◽  
pp. 59-66
Author(s):  
Abdul Aziz Ibrahim
Keyword(s):  
Froude Number ◽  
Dimensional Analysis ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Alluvial Rivers ◽  
Contraction Ratio ◽  
Scouring Process ◽  
Bed Material

Percubaan telah dibuat untuk menganalisa masalah hakisan dasar di sekitar tiang jambatan di dalam sungai lanar dengan penggunaan cerakinan dimensa. Proses hakisan sekitar tiang jambatan dipengaruhi oleh sebilangan angkubah-angkubah kompleks yang berkaitan. Hakisan di sekliling tiang jambatan didapati bergantung kepada dimensa jambatan dan saluran, Nombor Froude, nisbah pengecutan, ciri-ciri bahan dasar, dan parameter-parameter berhubung dengan alat-alat mengawal hakisan. Data terdahulu juga digunakan bagi menyokong kemasukan dan penyisihan beberapa angkubah yang penting. An attempt has been made to analyse the problem of the erosion around bridge piers in alluvial rivers with the help of dimensional analysis. The scouring process in the vicinity of a bridge pier is controlled by a number of complex interrelated variables. Scour around bridge piers is shown to depend primarily on the dimension of the pier and channel. Froude number, contraction ratio, properties of the bed material and parameters related to devices controlling the scour. Previous data are also employed to support the inclusion or exclusion of some of the important variables.

scholarly journals Turbulent Flow Structures and Scour Hole Characteristics around Circular Bridge Piers over Non-Uniform Sand Bed Channels with Downward Seepage

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1580 ◽  
Author(s):  
Chavan ◽  
Gualtieri ◽  
Kumar
Keyword(s):  
Turbulent Flow ◽  
Bridge Piers ◽  
Alluvial Rivers ◽  
Downward Seepage ◽  
Turbulent Statistics ◽  
Model Predictions ◽  
Scour Hole ◽  
Length Width ◽  
Bed Material ◽  
Good Agreement

In alluvial rivers bridge piers often cause local scour, a complex phenomenon as a result of the interaction between turbulent flow and bed material. In this paper, the results of an experimental study on the scour hole characteristics around single vertical pier sets on a non-uniform sand bed, under no seepage, and with downward seepage conditions, are described. In case of downward seepage, turbulent statistics, such as Reynolds stress, higher order moments, TKE-flux, and consequently sediment transport, decrease upstream of the pier, while increasing on both sides of it, where the enhanced erosive capacity of the flow results in an increase in the scour hole width. Moreover, the scour hole length shifts downstream. Empirical equations for the evaluation of scour hole characteristics, such as the length, width, area, and volume, including the downward seepage parameter, are proposed and experimentally tested. Model predictions give reasonably good agreement with the experimental data.

scholarly journals Mathematical Modeling of Local Scour at Slender and Wide Bridge Piers

2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Youssef I. Hafez
Keyword(s):  
Local Scour ◽  
Bridge Pier ◽  
Angle Of Repose ◽  
Bridge Piers ◽  
Bridge Scour ◽  
Pier Scour ◽  
Bed Scour ◽  
Bed Material ◽  
Bridge Pier Scour ◽  
Mitigation Methods

Most existing equations for predicting local scour at bridge piers suffer from overprediction of the scour depths which results in higher foundation costs. To tackle this problem, a mathematical model for predicting bridge pier scour is developed herein based on an energy balance theory. The present study equation was compared to commonly used bridge scour equations using scour field data in USA. The developed equation has several advantages among which we have the following: it adds to the understanding of the physics of bridge pier scour, is valid for slender and wide piers, does not suffer from overprediction of scour depths, addresses clear water and live bed scour, and includes the effects of various characteristics of the bed material such as specific gravity (or density), porosity, size, and angle of repose. In addition, the developed equation accounts for the debris effect and aids in the design of scour mitigation methods such as collars, side bars, slots, and pier protective piles.

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

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1251 ◽  
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.

scholarly journals Nose-Angle Bridge Piers as Alternative Countermeasures for Local Scour Reduction

2018 ◽  
Vol 13 (2) ◽  
pp. 110-120 ◽  
Author(s):  
Ibtesam Abudallah Habib ◽  
Wan Hanna Melini Wan Mohtar ◽  
Atef Elsaiad ◽  
Ahmed El-Shafie
Keyword(s):  
Froude Number ◽  
Local Scour ◽  
Bridge Piers ◽  
Scour Depth ◽  
Skew Angle ◽  
Flow Angle ◽  
Sediment Size ◽  
Low Froude Number ◽  
Skew Angles ◽  
Depth Reduction

This study investigates the performance nose-angle piers as countermeasures for local scour reduction around piers. Four nose angles were studied, i.e., 90°, 70°, 60° and 45° and tested in a laboratory. The sediment size was fixed at 0.39 mm whereas the flow angle of attack (or skew angle) was varied at four angles, i.e., skew angles, i.e., 0°, 10°, 20° and 30°. Scour reduction was clear when decreasing nose angles and reached maximum when the nose angle is 45°. Increasing the flow velocity and skew angle was subsequently increasing the scour profile, both in vertical and transversal directions. However, the efficiency of nose angle piers was only high at low Froude number less than 0.40 where higher Froude number gives minimal changes in the maximum scour depth reduction. At a higher skew angle, although showed promising maximum scour depth reduction, the increasing pier projected width resulted in the increase of transversal lengths.

scholarly journals Analysis of Water Flow Pressure on Bridge Piers considering the Impact Effect

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Yin-hui Wang ◽  
Yi-song Zou ◽  
Lue-qin Xu ◽  
Zheng Luo
Keyword(s):  
Water Flow ◽  
Coupling Effect ◽  
Highway Bridges ◽  
Element Model ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Water Current ◽  
Fluid Structure ◽  
Impact Effect ◽  
The Impact

In order to investigate the effects of water current impact and fluid-structure interaction on the bridge piers, the mechanism of water flow impact on the bridge pier is firstly studied. Then a finite element model of a bridge pier is established including the effects of water flow impact as well as the water circumferential motion around the pier. Comparative study is conducted between the results of water impact effect, fluid-structure coupling effect, theoretical analysis, and also the results derived using the formulas specified in the design codes home and abroad. The results show that the water flow force calculated using the formulas provided by the codes should be multiplied by an impact amplifier to account for the effect of flood impact on the bridge pier. When the flood flows around the pier, the fluid-structure coupling effect on the bridge pier can be neglected. The method specified in the China guidelines ofGeneral Code for Design of Highway Bridges and Culvertstends to provide a larger result of the water flow force.

scholarly journals Prediction of flow around a sharp-nosed bridge pier: influence of the Froude number and free-surface variation on the flow field

2019 ◽  
Vol 58 (4) ◽  
pp. 582-593
Author(s):  
Recep Kahraman ◽  
Matthew Riella ◽  
Gavin R. Tabor ◽  
Mohsen Ebrahimi ◽  
Slobodan Djordjević ◽  
...  
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Froude Number ◽  
Bridge Pier ◽  
Surface Variation

scholarly journals Experimental Investigation of Local Scour Protection for Cylindrical Bridge Piers Using Anti-Scour Collars

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1515 ◽  
Author(s):  
Shunyi Wang ◽  
Kai Wei ◽  
Zhonghui Shen ◽  
Qiqi Xiang
Keyword(s):  
Protective Effect ◽  
Local Scour ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Experimental Program ◽  
Design Parameters ◽  
External Diameter ◽  
River Sand ◽  
Bed Scour ◽  
Scour Protection

Local scour of bridge piers is one of the main threats responsible for bridge damage. Adopting scour countermeasures to protect bridge foundations from scour has become an important issue for the design and maintenance of bridges located in erodible sediment beds. This paper focuses on the protective effect of one active countermeasure named an “anti-scour collar” on local scour around the commonly used cylindrical bridge pier. A cylindrical pier model was set up in a current flume. River sand with a median particle size of 0.324 mm was selected and used as the sediment in the basin. A live-bed scour experimental program was carried out to study the protective effect of an anti-scour collar by comparing the local scour at a cylindrical bridge pier model with and without collar. The effects of three design parameters including collar installation height, collar external diameter and collar protection range, on the scour depth and scour development were investigated parametrically. According to the experimental results, it can be concluded that: the application of an anti-scour collar alleviates the local scour at the pier effectively; and the protection effect decreases with an increase in the collar installation height, but increases with an increase in the collar external diameter and the protection range. Design suggestions for improving the scour protective effect of the anti-scour collar are summarized and of great practical guiding significance to the development of anti-scour collars for bridge piers.

Seismic Strengthening of Reinforced-Concrete Multicolumn Bridge Piers

2007 ◽  
Vol 23 (3) ◽  
pp. 635-664 ◽  
Author(s):  
Chris P. Pantelides ◽  
Jeffrey B. Duffin ◽  
Lawrence D. Reaveley
Keyword(s):  
Reinforced Concrete ◽  
Bridge Pier ◽  
Fiber Reinforced Polymer ◽  
Bridge Piers ◽  
Seismic Rehabilitation ◽  
Frp Composite ◽  
Reinforced Polymer ◽  
Pile Caps ◽  
Rehabilitation Measures

The analysis, seismic rehabilitation measures, and in-situ performance of a reinforced-concrete (RC) bridge pier subjected to quasi-static loads are presented. The bridge was built in 1963 and was designed for gravity and wind but not seismic loads. The reinforcement details are compared with AASHTO requirements for seismic zones 3 and 4. The bridge pier was rehabilitated with steel dowels connecting the piles to the pile caps and RC grade beam connecting the three pile caps; carbon Fiber-Reinforced-Polymer (FRP) composite jackets were used to rehabilitate the columns, cap beam, and T-joints. An analytical model is presented that includes the effects of soil-pile-structure interaction and the seismic rehabilitation measures. Critical events in the experimental performance of the bridge pier are identified. Comparisons are made between the pier's performance and that of other piers tested in situ at the same site that were rehabilitated with incremental measures.

scholarly journals Origin of the scaling laws of sediment transport

2017 ◽  
Vol 473 (2197) ◽  
pp. 20160785 ◽  
Author(s):  
Sk Zeeshan Ali ◽  
Subhasish Dey
Keyword(s):  
Sediment Transport ◽  
Froude Number ◽  
Scaling Laws ◽  
Scaling Law ◽  
Bedload Transport ◽  
Inertial Range ◽  
Channel Width ◽  
Densimetric Froude Number ◽  
Relative Roughness ◽  
Contraction Ratio

In this paper, we discover the origin of the scaling laws of sediment transport under turbulent flow over a sediment bed, for the first time, from the perspective of the phenomenological theory of turbulence. The results reveal that for the incipient motion of sediment particles, the densimetric Froude number obeys the ‘(1 +  σ )/4’ scaling law with the relative roughness (ratio of particle diameter to approach flow depth), where σ is the spectral exponent of turbulent energy spectrum. However, for the bedforms, the densimetric Froude number obeys a ‘(1 +  σ )/6’ scaling law with the relative roughness in the enstrophy inertial range and the energy inertial range. For the bedload flux, the bedload transport intensity obeys the ‘3/2’ and ‘(1 +  σ )/4’ scaling laws with the transport stage parameter and the relative roughness, respectively. For the suspended load flux, the non-dimensional suspended sediment concentration obeys the ‘ − Z ’ scaling law with the non-dimensional vertical distance within the wall shear layer, where Z is the Rouse number. For the scour in contracted streams, the non-dimensional scour depth obeys the ‘4/(3 −  σ )’, ‘−4/(3 −  σ )’ and ‘−(1 +  σ )/(3 −  σ )’ scaling laws with the densimetric Froude number, the channel contraction ratio (ratio of contracted channel width to approach channel width) and the relative roughness, respectively.

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.

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