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.

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 Experimental on the protective performance of column bridge pier anti-scouring device

2021 ◽  
Vol 248 ◽  
pp. 01015
Author(s):  
Zhejiang Chen ◽  
Liang Liu ◽  
Yonglin Hu ◽  
Nan Ye ◽  
Xiaoli Shen ◽  
...  
Keyword(s):  
Optimal Parameter ◽  
Reduction Rate ◽  
Local Scour ◽  
Bridge Pier ◽  
Design Parameters ◽  
Water Tank ◽  
Protective Device ◽  
Measuring Point ◽  
Test Range ◽  
The Impact

Because of the problem of local scour caused by the change of the flow structure caused by the water-resistance of the column bridge pier, the theoretical analysis, and indoor water tank test were used to study the effect of installing a new anti-scouring device in front of the bridge pier on the local scour reduction effect; the influence of the main design parameters such as the height of the protective device, the angle of the protective device and the distance from the protective device to the bridge pier on the local scour of the bridge pier was selected, and the optimal parameter design combination was selected. The test results show that: under the same water flow conditions, the maximum scour depth reduction rate of the measuring point under the protection of the protective device is 48.4% to 74.2% compared with the unprotected scour; the reduction rate of the bridge pier is relative to the relative height of the device and the device equivalent. The angle and the distance between the device and the bridge pier are related, and the shock reduction rate decreases with the increase of the flow intensity. In the test range, the ratio of the device height to the water depth is 2/3, the device angle is 60 °, and the distance from the bridge pier is 3. When the diameter of the pier is doubled, the effect of reducing the impact on the pier is the best.

scholarly journals Local Scour of Bridge Pier Sited on a Multi-Layered Sedimentary Bed in Rivers

2020 ◽  
Vol 144 ◽  
pp. 01008
Author(s):  
Shaolin Yue ◽  
Huan Zhou ◽  
Wenlong Zhu ◽  
Minxi Zhang
Keyword(s):  
Local Scour ◽  
Bridge Pier ◽  
Maximum Depth ◽  
Bridge Piers ◽  
Scour Depth ◽  
Bridge Safety ◽  
Particle Sorting ◽  
River Bed ◽  
Weihe River ◽  
Sediment Particles

The riverbeds or sea beds are usually composed of multi-layers of sediments. The scour around bridge piers sited on such beds is vital to the bridge safety, but is still very difficult to be predicated as its complicated interaction between the flow and bed layers. A simple model is proposed in this study for calculating the local scour maximum depth around bridge piers sited on multi-layer of sedimentary bed, which is based on HEC-18 formula revised by Richardson and Davis (2001) and the formula of the repose angle of sediment particles proposed by Cheng (1993). This model considers the particle sorting when the scour proceeds. An application of the model into the local scour depth of Guopan bridge pier sited on the Weihe River bed in Baoji city of China preliminarily demonstrates its reliability to calculate the local scour maximum depth around bridge piers sited on multi-layer of sedimentary bed.

scholarly journals Effects of Dynamical Change in Water Level on Local Scouring around Bridge Piers Based on In-Situ Experiments

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3015
Author(s):  
Takuma Kadono ◽  
Sho Kato ◽  
Shinichiro Okazaki ◽  
Toshinori Matsui ◽  
Yoshio Kajitani ◽  
...  
Keyword(s):  
Water Level ◽  
Local Scour ◽  
Bridge Pier ◽  
Angle Of Repose ◽  
Bridge Piers ◽  
Scour Depth ◽  
Water Level Change ◽  
Protection Zone ◽  
Level Change ◽  
In Situ Experiments

To evaluate the stability of bridge piers affected by the local scouring, the existing formulas for estimating the maximum local scour depth have been developed based on the results of experiments conducted under a constant water level. However, the applicability of these formulas to the cases where the water level rises and falls, such as a water level change in a real river, is not clear. In this study, water flow experiments were conducted on cylindrical and oval bridge pier models to investigate the effect of iterated water level change on the progression of local scour around piers. Results of experiments with cylindrical and oval pier showed that the local scour depth and length increased by an iterated action of the water level change; however, these values converged after the number of iterated actions reached a certain time. The local scour length at upstream of the bridge pier was approximately 1.8 times larger than the theoretical value, which was calculated through the local scour depth and angle of repose in water. The local scour length is an important parameter for defining the streambed protection zone, which is one of the measures against local scour, and we showed that the streambed protection zone needs to be defined more widely.

scholarly journals Application of Improved GMDH Models to Predict Local Scour Depth at Complex Bridge Piers

2020 ◽  
Vol 6 (1) ◽  
pp. 69-84 ◽  
Author(s):  
Habibeh Ghodsi ◽  
Mohammad Javad Khanjani
Keyword(s):  
Local Scour ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Group Method ◽  
Scour Depth ◽  
Empirical Equations ◽  
Depth Prediction ◽  
Pile Cap ◽  
Data Points ◽  
Statistical Criteria

Scour depth prediction is a vital issue in bridge pier design. Recently, good progress has been made in the development of artificial intelligence (AI) to predict scour depth around hydraulic structures base such as bridge piers. In this study, two hybrid intelligence models based on combination of group method of data handling (GMDH) with harmony search algorithm (HS) and shuffled complex evolution (SCE) have been developed to predict local scour depth around complex bridge piers using 82 laboratory data measured by authors and  615 data points from published literature. The results were compared to conventional GMDH models with two kinds of transfer functions called GMDH1 and GMDH2. Based upon the pile cap location, data points were divided into three categories. The performance of all utilized models was evaluated by the statistical criteria of R, RMSE, MAPE, BIAS, and SI. Performances of developed models were evaluated by experimental data points collected in laboratory experiments, together with commonly empirical equations. The results showed that GMDH2SCE was the superior model in terms of all statistical criteria in training when the pile cap was above the initial bed level and completely buried pile cap. For a partially-buried pile cap, GMDH1SCE offered the best performance. Among empirical equations, HEC-18 produced relatively good performances for different types of complex piers. This study recommends hybrid GMDH models, as powerful tools in complex bridge pier scour depth prediction.

scholarly journals CFD Simulation of Local Scouring Around Bridge Pier

2019 ◽  
Vol 9 (1) ◽  
pp. 1870-1880
Keyword(s):  
Cfd Simulation ◽  
Flow Behavior ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Local Scour ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Multiphase Model ◽  
Model Studies ◽  
Dimensional Simulation

The threat of local scour around bridge piers has been in research for many years. According to the various studies, local scour around the bridge pier is the prime cause for most of the bridge failures. The main objective of the present study was to investigate the flow behavior and the scour phenomenon around the bridge piers of various shapes namely Circular, Elliptical, Square and Streamlined. Local scouring depends on various factors like depth of flow, upstream flow conditions, pier shape and dimensions. Here, we have taken only pier shape as the primary factor and kept other factors constant. The numerical simulations were even carried out using CFDFluent, Eulerian multiphase model, k–epsilon turbulence model, to elaborate the physics behind the scour formation. CFD simulation tool can be used for wide understanding of the flow behavior around the bridge piers even without physical model studies because it saves time and money as compared to experimental studies. Three dimensional simulation of flow behavior around four pier shapes indicates that the streamlined pier is the most efficient pier to use as it allows the flow to pass smoothly around it creating less obstruction to the flow and hence creating less chances of local scouring near the pier toe.

Numerical Simulation of Temporal Evolution of Local Scour in Bridge Pier with Nonuniform Sediment

2011 ◽  
Vol 250-253 ◽  
pp. 3610-3614 ◽  
Author(s):  
Mohammad J. Aarabi ◽  
Mohammad R. Chamani ◽  
Amir A. Dehghani ◽  
Keyvan Asghari
Keyword(s):  
Numerical Simulation ◽  
Time Variation ◽  
Temporal Evolution ◽  
Local Scour ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Nonuniform Sediment ◽  
Natural Rivers

Due to economical and serviceability reasons, local scour must be considered in the design of bridge piers. Although beds of natural rivers consist of nonuniform sediments, but most researches in this subject were carried out with uniform sediments. In nonuniform sediments case, the effect of sheltering of the finer particles by the coarser ones may alter the scour process. In this paper, the time-variation of local scour with nonuniform sediments around a cylinder pier is simulated using SSIIM software. This study shows that the SSIIM is capable of predicting the temporal evolution of local scour in bridge piers with nonuniform 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.

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