Effect of Meander on Bridge Pier Scour

Lots of work regarding the scour around bridge piers in straight channelhave been done in the past by many researchers. Many factors which affectscour around piers such as shape of piers, size, positioning and orientationetc. have been studied in detail by them. However, similar studies inmeandering channels are scanty. Very few researchers have studied theeffect of angular displacement which has considerable effects of scouraround bridge piers.In this paper an attempt has been made to carry out a detailed study ofangular displacement on scour. A constant diameter bridge pier of circularshape has been tested in a meandering channel bend with bend angle as 800 .The test bed was prepared by using uniform sand having d50 as 0.27 mmand run was taken for a discharge of 2.5 l/s.

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Temporal variation of clear water scour at cylindrical bridge piers

Canadian Journal of Civil Engineering ◽

10.1139/l06-054 ◽

2006 ◽

Vol 33 (8) ◽

pp. 1098-1102 ◽

Cited By ~ 17

Author(s):

A Melih Yanmaz

Keyword(s):

Temporal Variation ◽

Semiempirical Method ◽

Bridge Pier ◽

Bridge Piers ◽

Recent Sediment ◽

Clear Water ◽

Design Flood ◽

Pier Scour ◽

Time To Peak ◽

Bridge Pier Scour

Computation of temporal variation of clear water scour is important for the design of bridge pier footings. Previous studies indicated that very long flow duration was needed to achieve equilibrium scouring situations. However, the corresponding durations in the prototype conditions may yield considerably larger values than time-to-peak of the design flood. Therefore, there is a need to estimate the temporal variation of scour depth. This study deals with the development of a new semiempirical method for temporal variation of clear water scour at cylindrical bridge piers using the sediment continuity approach. A recent sediment pickup function proposed for sloping beds is used to formulate the rate of sediment transport out of the scour hole. Results of the proposed method agree well with experimental results. The findings of the proposed method are also compared with some recent empirical methods.Key words: bridge, pier, scour, clear water, sediment pickup.

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Effects of Spur Dyke’s Orientation on Bed Variation in Channel Bend

Hydro Science & Marine Engineering ◽

10.30564/hsme.v3i2.3834 ◽

2021 ◽

Vol 3 (2) ◽

Author(s):

Mohammad Athar ◽

Talib Mansoor ◽

Nishank Aggarwal

Keyword(s):

Angular Displacement ◽

Velocity Shear ◽

Bridge Piers ◽

Geometrical Parameters ◽

Meandering Channel ◽

Sediment Size ◽

Channel Bend ◽

Outer Bank ◽

Main Emphasis ◽

Present Thesis

Spur dykes also known as Groynes are often used to either divert or attract the flow from the main structure to safeguard their life. Those structures may be bridge piers, abutments or any similar hydraulics structures. Spur dykes are also used to save the cutting of banks on concave side of stream. Lots of work have been done in recent past on spur dykes by many investigators in which various hydraulic and geometrical parameters of spur dykes such as discharge, sediment size, flow velocity, shear stress, spur dykes shape, size and submergence etc. are studied in detail. But mostly all the studies were pointed out in straight open channels. Very few studies were done in curved channel and only their similar effects were studied. In present thesis main emphasis is given to study the effect of orientation and location of spur dykes in meandering channel on the bed of downstream side. In the present study experimental work has been carried out in 80° bend and constant discharge (Q = 4.5 l/s) is allowed to pass in channel without spur dyke. It is found that maximum scouring occurs at angular displacement θ = 60° to 80° in the vicinity of outer bank. To minimize this scouring, spur dyke has been installed at angular displacement θ = 20°, 40° & 60° by changing the dyke angle α = 60°, 90° & 120° respectively. It is found that scouring at θ = 60° is reduced by installing spur dyke at angular displacement θ = 40° which is oriented at α = 60° and scouring at θ = 80° is reduced by installing spur dyke at angular displacement θ = 60° which is oriented at α = 60°.

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Prediction of Bridge Pier Scour Depth and Field Scour Depth Monitoring

E3S Web of Conferences ◽

10.1051/e3sconf/20184003007 ◽

2018 ◽

Vol 40 ◽

pp. 03007

Author(s):

Fong-Zuo Lee ◽

Jihn-Sung Lai ◽

Yuan-Bin Lin ◽

Kuo-Chun Chang ◽

Xiaoqin Liu ◽

...

Keyword(s):

Numerical Model ◽

Real Time ◽

Earthquake Engineering ◽

Model Simulation ◽

Bridge Pier ◽

Bridge Piers ◽

Scour Depth ◽

Pier Scour ◽

River Bed ◽

Bridge Pier Scour

In practice, it is a major challenge in real-time simulation and prediction of bridge pier scour depth, especially using 3-D numerical model. The simulation time spend too much to use 3-D numerical model simulation and inefficiently to predict bridge pier scour depth in real-time. With heavy rainfall during flood season in Taiwan, abundant sediment with flash flood from upstream watershed is transported to downstream river reaches and transportation time is limited within one day. The flood flow tends to damage bridge structures and affect channel stabilization in fluvial rivers. In addition, the main factors affecting the erosional depth around bridge piers and river bed stabilization are hydrological and hydrographic characteristics in river basin, the scouring and silting of river bed section near the bridge piers, the bridge geometry and protection works of bridge piers. Therefore, based on the observed rainfall data provided by the Central Weather Bureau and the hydrological conditions provided by the Water Resources Agency during flood event as the boundary condition, we develop an effective simulation system for scour depth of bridge piers. The scour depth at the bridge pier is observed by the National Center for Research on Earthquake Engineering for model calibration. In this study, an innovative scour monitoring system using vibration-based Micro-Electro Mechanical Systems (MEMS) sensors was applied. This vibration-based MEMS sensor was packaged inside a stainless sphere with the proper protection of the full-filled resin, which can measure free vibration signals to detect scouring/deposition processes at the bridge pier. It has demonstrated that the measurement system for monitoring bridge scour depth evolution is quite successful in the field.

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A New Practical Method to Simulate Flood-Induced Bridge Pier Scour—A Case Study of Mingchu Bridge Piers on the Cho-Shui River

Water ◽

10.3390/w8060238 ◽

2016 ◽

Vol 8 (6) ◽

pp. 238 ◽

Cited By ~ 13

Author(s):

Jian-Hao Hong ◽

Wen-Dar Guo ◽

Yee-Meng Chiew ◽

Cheng-Hsin Chen

Keyword(s):

Practical Method ◽

Bridge Pier ◽

Bridge Piers ◽

Pier Scour ◽

Bridge Pier Scour

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Mathematical Modeling of Local Scour at Slender and Wide Bridge Piers

Journal of Fluids ◽

10.1155/2016/4835253 ◽

2016 ◽

Vol 2016 ◽

pp. 1-19 ◽

Cited By ~ 7

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.

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