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NEURAL NETWORK MODELING FOR ESTIMATION OF scour depth AROUND BRIDGE PIERS

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Journal of Hydrodynamics 2007年第3期19卷 378-386页

作者： LEE T. L. JENG D. S. ZHANG G. H. HONG J. H. Department of Construction Technology Leader University Tainan 709 China School of Civil Engineering The University of Sydney NSW 2006 Australia Department of Resource and Environment Leader University Tainan 709 China Department of Civil Engineering National Chung Hsing University Taichung 402 China

It is essential to predict the scour depth around bridge piers for hydraulic engineers involved in the economical design of bridge pier foundation. Conventional investigations have long been of the opinion that empirical scour prediction equations based on laboratory data over predict scour depths. In this article, the Back-Propagation Neural Network （BPN） was applied to predict the scour depth in order to overcome the problem of exclusive and the nonlinear relationships. The observations obtained from thirteen states in USA was verified by the present model. From the comparison with conventional experimental methods, it can be found that the scour depth around bridge piers can be efficiently predicted using the BPN.

关键词： Back-Propagation Neural Network （BPN） prediction bridge pier scour depth

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Particle swarm optimization model to predict scour depth around a bridge pier

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Frontiers of Structural and Civil Engineering 2020年第4期14卷 855-866页

作者： Shahaboddin SHAMSHIRBAND Amir MOSAVI Timon RABCZUK Department for Management of Science and Technology Development Ton Duc Thang UniversiyHo Chi Minh CityVietmam Faculty of Information Technology Ton Duc Thang UniversityHo Chi Minh CityVietnam Institute of Automation Kando Kalman Faculy of Electrical EngineeringObuda UniversiyBudapest 1034Hungary Department of Mathematics and Informatics J.Selye UniversityKomarno 94501Slovakia School of the Built Environment Oxford Brookes UniversityOxford OX30BPUK Instiute of Structural Mechanics Bauhaus-Universitat WeimarWeimar 99423Germany

scour depth around bridge piers plays a vital role in the safety and stability of the bridges.The former approaches used in the prediction of scour depth are based on regression models or black box models in which the first one lacks enough accuracy while the later one does not provide a clear mathematical expression to easily employ it for other situations or cases.Therefore,this paper aims to develop new equations using particle swarm optimization as a metaheuristic approach to predict scour depth around bridge piers.To improve the efficiency of the proposed model,individual equations are derived for laboratory and field data.Moreover,sensitivity analysis is conducted to achieve the most effective parameters in the estimation of scour depth for both experimental and filed data sets.Comparing the results of the proposed model with those of existing regression-based equations reveal the superiority of the proposed method in terms of accuracy and uncertainty.Moreover,the ratio of pier width to flow depth and ratio of d50 (mean particle diameter)to flow depth for the laboratory and field data were recognized as the most effective parameters,respectively.The derived equations can be used as a suitable proxy to estimate scour depth in both experimental and prototype scales.

关键词： scour depth bridge design and construction particle swarm optimization computational mechanics artificial intelligence bridge pier

scour depth AND FLOW PATTERN OF ERODING PLANE JETS

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International Journal of Sediment Research 2004年第1期19卷 15-27页

作者： A.KURNIAWAN M.S.ALTINAKAR W.H.GRAF Ecole Polytechnique Federale Ecole Polytechnique Federate LRH Lausanne NCCHE Res. Assist. Res. Assoc. Switzerland USA University of Mississippi presently Prof.

Local scour may occur when a hydraulic structure is positioned in a channel with an erodible bed. Herewith investigated experimentally are the erosion and flow pattern due to a water jet passing over a channel bed at the asymptotic (final) state. The development of the scour hole, its maximum scour depth and length, are recorded and compared with available scour-depth relations. Two sets of experiments (see Table 1) were carried out. Set 1 (3 runs) was concerned with measuring the vertical instantaneous velocity distribution in the scour hole. The scour hole at the asymptotic (final) state, t = 100 [h] was investigated. Set 2 (5 runs) was concerned with studying the physics of scouring. The scour hole at about mid-state, t = 0.5 [h], was investigated; subsequently the scour-hole depth was linearly extended on the semi-log scale to 72 [h]; no velocity measurements were performed. The present data are put in context with some (popular) existing relations; recommended is a modification of some of these rel

关键词： Local scour Eroding jet scour depth Flow pattern

Experimental Study of Submergence Ratio on Local scour Around a Square Pile in Steady Flow

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中国海洋大学学报:英文版 2023年第5期22卷 1277-1288页

作者： DU Shengtao WU Guoxiang LIANG Bingchen ZHU David Z WANG Risheng School of Civil and Environmental Engineering Ningbo UniversityNingbo 315211China College of Engineering Ocean University of ChinaQingdao 266100China Shandong Provincial Key Laboratory of Ocean Engineering Ocean University of ChinaQingdao 266100China College of Civil Engineering Shandong Jiaotong UniversityJinan 250357China

scour around a submerged square pile was realized experimentally in a steady flow to study the effects of flow depth on local scour.Flow depth to pile height ratios ranging from 1.5 to 5 in uniform sand and 2 to 5 in non-uniform sand were tested in the approaching flow velocity to critical velocity(larger than which the sediment particle is motivated)ratios of 0.56 and 1.03,respectively.The influences of flow depth were investigated on the basis of analysis of the three-dimensional topography,temporal maximum scour depth,bed profile development,and equilibrium scour depth.Results showed that the maximum scour depth was at the upstream corners of the pile other than at the stagnation point.The evolutions of the maximum scour depth data in non-uniform sand were well fitted with a recent exponential function,which characterized the initial,developing,and equilibrium stages of scour depth.The scour hole slopes upstream of the pile were found to be parallel to each other in the process of each test and were mainly governed by the sediment repose underwater.The equilibrium scour depth varied slightly with flow depth when the submergence ratio was larger than 1 in uniform sand while it was 2 in non-uniform sand.The armoring effects of coarse sediment particles markedly reduced the sediment transport in non-uniform sand despite the 0.34 increment in non-uniformity.

关键词： non-uniform sand square pile local scour submerged scour depth

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LOCAL scour depth AROUND SPURS IN THE LOWER YELLOW RIVER

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International Journal of Sediment Research 2002年第3期17卷 244-249页

作者： Baishan ZHANG,Jiye MA,Zhilin WEI Wuhan 430072 China. Department of Civil Engineering Beijing University of Aeronautics 37 Xueyuan Road Beijing100083 China Henan Bureau of Yellow River Zhengzhou 450003 China. Wuhan University

A formula for the computations of local scour depth at the head of spurs is derived according to the equilibrium principle of incipient motion of sediment particle. The proposed formula is verified with laboratory data and field measurements. In the derivation of this formula, two different scour resistance forces, the cohesive force and the gravitational force, are considered, and the integrated coefficient is calibrated using data from the Lower Yellow River.

关键词： Spur scour depth Lower Yellow River

Experimental Study on Effect of Ogival Bridge Pier on scour Hole depth

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Experimental Study on Effect of Ogival Bridge Pier on Scour ...

A revisit of the local scour around bridge piers under an ice-covered flow condition-An experimental study

第六届国际流体力学会议

作者： Alireza Masjedi B. Zeraat M. Hydarnejad Islamic Azad University Branch Ahwaz MSc Khuzestan Science and Research BranchIslamic Azad University Khuzestan Science and Research Branch Islamic Azad University

Investigation on scoring and determination of depth of scoring are among the most important issues in square pier designation with model ogival pier was measured in a laboratory flume with 180° bend with a relative curvature of bend of 4.67 under clear-water.One ogival model pier was used for the study in different Froude numbers and positions were tested.Natural sand with uniform graining of d50=1.3 mm and uniformity factor of 1.4 were used as bed materials.The results of the model study indicated that the maximum depth of scour is highly dependent on the experimental duration.The results of this study show that,while ogival pier is placed in the bend,the maximum scouring depth is occurs in position of 60°.Also it was observed that in all positions,the scouring depth increases as the Froude number increasing.

关键词： ogival pier position Froude number 180° bend scour depth

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Journal of Hydrodynamics 2021年第5期33卷 928-937页

作者： Jun Wang Kui Wang Bi-he Fang Jueyi Sui School of Civil and Hydraulic Engineering Hefei University of TechnologyHefei 230009China School of Engineering University of Northern British ColumbiaPrince GeorgeBCCanada

In this study,by changing both pier diameters and particle sizes of sand bed in flume experiments,the scour process around cylindrical bridge piers under an ice-covered flow condition has been investigated.It is found that the appearance of an ice cover on the water surface caused a deeper and wider scour hole in comparison with that in an open flow with identical flow rates,implying a larger volume of scour hole under an ice-covered flow condition.Similar to the scouring process at a bridge pier under an open flow condition,both the depth and volume of a scour hole increase with the flow velocity and pier diameter.Comparing with results under an open flow condition,for identical flow rates,the maximum depth of a scour hole under an ice-covered flow condition increased by about 20%-30%,and both the scour area and volume of a scour hole increased by about 40%-50%.A flow at Froude number of 0.15 is the demarcation point for assessing an obvious impact of an ice cover on the local scour around a bridge pier in this experimental study.Using data collected from laboratory experiments,equations have been developed to calculate the maximum scour depth,scour area and scour volume.Results of present study have been compared with those of others.

关键词： Bridge pier ice cover local scour scour area scour depth scour volume

Investigation on the Local scour Beneath Piggyback Pipelines Under Clear-Water Conditions

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China Ocean Engineering 2021年第3期35卷 422-431页

作者： Sahar ASRARI Habib HAKIMZADEH Nazila KARDAN Faculty of Civil Engineering Sahand University of TechnologySahandIran Department of Civil Engineering Azarbaijan Shahid Madani UniversityTabrizIran

A piggyback pipeline consists of two pipes such that the secondary line rides on the main pipe with a fixed distance between two pipes in length.The novel strategy is utilized in offshore areas instead of a single flow line.In this regard,there are only a handful of experimental and numerical studies investigating the effect of scour below a piggyback pipeline under steady current.Hence,this study focuses on examining the influential factors on scouring due to steady current including the pipe diameter and the gap between pipes through numerical simulations and experimental tests.Accordingly,at the first phase of the research,a single pipe was established and tested in laboratory to compare the results with those of an empirical equation.After finishing experimental verifications,piggyback pipelines were also assembled to study the scouring under steady current conditions.It was concluded that by increasing the gap distance between the pipes,the maximum scour depth decreases;however,an increase in the small pipe’s diameter results in a larger maximum scour depth.Secondly,numerical simulations were carried out using the FLOW-3D software which was found to be a suitable tool for the numerical investigation of this study.Finally,the numerical results have been compared with the corresponding experimental data and a relatively good agreement was achieved between them.

关键词： local scour piggyback pipeline scour depth numerical simulation

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Ring columns as pier scour countermeasures

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International Journal of Sediment Research 2011年第3期26卷 353-363页

作者： Jen-Hao CHENG Han-Peng SHIH Jen-Wei CHANG Candidate in Program of Civil and Hydraulic Engineering Feng Chia UniversityTaichungTaiwanChina Department of Water Resources Engineering and Conservation The University of Feng ChiaTaiwan.China

Ring columns placed upstream of a bridge pier to protect it from local scouring are typical scouring countermeasures.A series of experiments are conducted under clear-water steady flow（V/V;≤1）with uniform sediment.Various parameters,such as ring column diameter,thickness,height,and distances between ring columns and the pier,are considered in the study.Laboratory data are used to assess the influence of each parameter on pier scour depth.Experimental results indicate that pores in ring columns provide space for energy dissipation of the downflow,hence,effectively reduce the flow energy impacting the downstream pier.The friction force of ring columns caused by their geometric shape reduces kinetic energy and pier scour depth.In general,it is found that the best pattern of ring columns reduce pier scour depth by 65%.

关键词： Ring columns Local scour Energy dissipation scour depth