Download or read book Local Scour Around Differently Shaped Bridge Piers An Experimental Investigation written by Kaleem Afzal and published by GRIN Verlag. This book was released on 2020-02-06 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bachelor Thesis from the year 2019 in the subject Physics - Mechanics, University of Engineering & Technology Peshawar, language: English, abstract: The objective of the study is to conduct laboratory model testing to investigate and compare scour hole depth of the diamond, square and elliptical scaled model of bridge piers in a cohesion less bedding material under clear water and to propose the most efficient cross section of the bridge pier, having less Local scour around piers under steady clear-water condition was studied experimentally for a variety of configuration, including different sizes and shapes of piers. Total number of forty experiments were performed in the flume using diamond, square and elliptical shape. The scouring around the square shape was found maximum and at elliptical shape was the least. The main reason was obstruction in flow area that was more in case of the square and less in case of the elliptical shape. However, the diamond shaped has the intermediate scouring under same condition. Local scour is a complex phenomenon involving three-dimensional flow, typically developed around piers founded in movable bed rivers. Local scour can lead to partial failure or to collapse of bridge piers because of the high flood velocity. The cost of large bridges, with common and special complex piers, justifies carrying out an accurate prediction of scour depth, for both economic and safety reasons, which in turn leads to the interest of hydraulic engineers in predicting the equilibrium scour depth.

Download or read book Experimental and Numerical Study of Local Scour Around Side by side Bridge Piers Under Ice covered Conditions written by Mohammad Reza Namaee and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Local scour around piers and abutments is one of the main causes of the collapse of many bridges constructed inside rivers. Many researchers have conducted various studies to predict the maximum depth of a scour hole around bridge piers and abutments. However, most of them have been done in small-scale laboratory flumes and specifically for the open channel condition. Besides, most of the existing research on bridge piers uses uniform sediment which is not an appropriate representative of natural river systems. This can result in excessively conservative design values for scour in low risk or non-critical hydrologic conditions. The most severe cases of bridge pier scouring occur in cold regions when the surface of water turns into ice in which, an additional boundary layer is being added to the water surface, which leads to significant changes in the flow field and scour pattern around bridge piers. Ice cover also causes the maximum flow velocity to move closer to the channel bed.

Download or read book Local Scour Around Bridge Piers written by Hsieh Wen Shen and published by . This book was released on 1968 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book River Mechanics written by Hsieh Wen Shen and published by . This book was released on 1971 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scouring written by H.N.C. Breusers and published by CRC Press. This book was released on 2020-08-13 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Information and technical data concerning scouring/erosion caused by water fl in rivers and streams. More specifically, how certain structures exaggerate this natural process by restricting water flow, causing constriction and loc scour. Material presented is from both field studies and laboratories

Download or read book Experimental Study of Local Scour Around Side by Side Bridge Piers Under Ice Covered Flow Conditions written by Jueyi Sui and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A precise prediction of maximum scour depth (MSD) around piers under ice-covered conditions is crucial for the safe design of the bridge foundation. Due to the lack of information for local scour under ice-covered flow condition, it is extremely hard to give proper estimation of MSD. In the current study, a set of flume experiments were completed to investigate local scour around four pairs of circular bridge piers with nonuniform bed materials under open channel, smooth and rough ice cover conditions. Three different bed materials with median particle size of 0.47, 0.50, and 0.58 mm were used to simulate natural river conditions. Regardless of pier size, the maximum scour depths were observed in front of the piers under all flow conditions. Additionally, a smaller pier size and a larger space between piers yield a smaller scour depth. Results showed that the maximum scour depth decreases with increase in the grain size of armor layer. The distribution of vertical velocity shows that the strength of downfall velocity is the greatest under rough ice cover. Empirical equations were developed to estimate the maximum scour depth around side-by-side bridge piers under both open-channel and ice-covered flow conditions.

Download or read book Local Scour Around Bridge Piers in Pressure Flow written by Laila M. Abed and published by . This book was released on 1991 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Study of the Phenomenon of Local Scour Around Bridge Piers written by Nangantani Davies Godfrey Mtundu and published by . This book was released on 1980 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bridge Scour written by Bruce W. Melville and published by Water Resources Publication. This book was released on 2000 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A comprehensive state-of-the-art treatment of scour and bridge foundations - both a handy reference text and a manual for the practicing bridge designer."--Publisher.

Download or read book Estuaries and Coastal Zones in Times of Global Change written by Kim Dan Nguyen and published by Springer Nature. This book was released on 2020-02-28 with total page 843 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of extended papers based on presentations given during the ICEC 2018 conference, held in Caen, France, in August 2018. It explores both the limitations and advantages of current models, and highlights the latest developments concerning new numerical schemes, high-performance computing, multi-physics and multi-scale methods, and better interaction with field or scale model data. Accordingly, it addresses the interests of practitioners, stakeholders, researchers, and engineers active in this field.

Download or read book Scour Around Circular Bridge Piers at High Froude Numbers written by Subhash Chandra Jain and published by . This book was released on 1979 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of laboratory experiments on scour around circular piers in cohesionless bed material at high Froude numbers, F, up to 1.5 are presented. The scour depths in sediment transport regime (F is greater than F sub c) first slightly decreases and then increases with the increase in the Froude number. A formula to predict the scour depth at Froude numbers (F-F sub c) is equal to or greater than 0.15, is developed. The limitations of some of the existing predictors of local scour are discussed, and a new formula to predict the maximum clearwater scour is proposed.

Download or read book Physical Modeling of Local Scour Around Complex Bridge Piers written by Seung Oh Lee and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Local scour around bridge foundations has been recognized as one of the main causes of bridge failures. The objective of this study is to investigate the relationships among field, laboratory, and numerical data for the purpose of improving scour prediction methods for complex bridge piers. In this study, three field sites in Georgia were selected for continuous monitoring and associated laboratory models were fabricated with physical scale ratios that modeled the full river and bridge cross sections to consider the effect of river bathymetry and bridge geometry. Three different sizes of sediment and several geometric scales of the bridge pier models were used in this study to investigate the scaling effect of relative sediment size, which is defined as the ratio of the pier width to the median sediment size. The velocity field for each bridge model was measured by the acoustic Doppler velocimeter (ADV) to explain the complicated hydrodynamics of the flow field around bridge piers as guided by the results from a numerical model. In each physical model with river bathymetry, the comparison between the results of laboratory experiments and the measurements of prototype bridge pier scour showed good agreement for the maximum pier scour depth at the nose of the pier as well as for the velocity distribution upstream of each bridge pier bent. Accepted scour prediction formulae were evaluated by comparison with extensive laboratory and field data. The effect of relative sediment size on the local pier scour depth was examined and a modified relationship between the local pier scour depth and the relative sediment size was presented. A useful methodology for designing physical models was developed to reproduce and predict local scour depth around complex piers considering Froude number similarity, flow intensity, and relative sediment size.

Download or read book Wastewater Hydraulics written by Willi H. Hager and published by Springer Science & Business Media. This book was released on 2010-11-25 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second, enlarged edition of this established reference integrates many new insights into wastewater hydraulics. This work serves as a reference for researchers but also is a basis for practicing engineers. It can be used as a text book for graduate students, although it has the characteristics of a reference book. It addresses mainly the sewer hydraulician but also general hydraulic engineers who have to tackle many a problem in daily life, and who will not always find an appropriate solution. Each chapter is introduced with a summary to outline the contents. To illustrate application of the theory, examples are presented to explain the computational procedures. Further, to relate present knowledge to the history of hydraulics, some key dates on noteworthy hydraulicians are quoted. A historical note on the development of wastewater hydraulics is also added. References are given at the end of each chapter, and they are often helpful starting points for further reading. Each notation is defined when introduced, and listed alphabetically at the end of each chapter. This new edition includes in particular sideweirs with throttling pipes, drop shafts with an account on the two-phase flow features, as well as conduit choking due to direct or undular hydraulic jumps.

Download or read book Local Scour Around Bridge Piers Under Steady and Unsteady Flow Conditions written by Tony Andrew Bennetts and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Water Security and Sustainability written by Chandrashekhar Bhuiyan and published by Springer Nature. This book was released on 2021-02-22 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains selected peer-reviewed papers presented in the International Conference Down To Earth 2019, and is focused on Water Security and Sustainability. The topics covered in this book include sustainability of water resources, geospatial modelling and hydro-informatics, extreme hydrology (drought and flood), adaptation to climate-change impacts, vulnerability-risk-reliability-resilience, and hydrological risks in north-east India. The book also discusses innovative techniques and technologies for water resources assessment and management. Enriched with numerous case studies covering diverse topics, the book can be valuable for students, researchers, as well as industry professionals interested in water resources assessment, management and sustainable development.

Download or read book Design Relationships for Maximum Local Scour Depth for Bridge Pier Groups written by Mehrdad Nazariha and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation of local scour at pier groups has been conducted with the aim of developing design recommendations and scour depth prediction equations for the bridge pier groups. A comprehensive series of steady uniform flow experiments was performed on groups of 2, 3, 4, and 6 model piers. All tests were conducted under clear-water scour conditions. Parameters governing local scour depth around bridge piers include: flow characteristics, sediment properties, and pier size and shape. The effects of these parameters on the maximum local scour depth for a single pier (D$\sb{\rm s}$), have been thoroughly investigated in the past. However, when design criteria developed for single piers are applied directly to pier groups, this approach ignores the following important group effects: (1) sheltering, (2) reinforcement, and (3) horse-shoe vortex (HSV) compression. Furthermore, the group effects will alter with changes in pier spacing, S, and flow angle of attack, $\beta$. This study, which investigates the local scouring process for the aforementioned groups of model bridge piers, and presents design relationships for predicting the corresponding maximum local scour depths, is an attempt to address this limitation in current design practice. Initially the local scour was examined for five different single pier diameters (0.0127 m, 0.018 m, 0.025 m, 0.033 m and 0.05 m). Having established single pier relationships, groups of 2, 3, 4, and 6 equally spaced piers were examined, while altering alignment to the flow and separation distances. For piers in line with the flow direction, downstream piers are sheltered by the upstream ones resulting in reducing scour depth around downstream piers. This effect diminishes with the increasing $\beta$ if there is only one row of piers i.e., 2 and 3 pier groups. In the case of 2 rows of piers aligned to the flow direction (i.e., 4- and 6-pier groups), there is a specific range of $\beta$ in which downstream piers are exposed to the flow. As $\beta$ increases, depending on pier spacing, the piers of one row may shelter the downstream piers of the other row. The reinforcement effect is significant only for small ratios of pier spacing/ pier diameter (S/d) when $\beta \le$ 10$\sp0$. In these ranges of S/d and $\beta$, the front piers are scoured more than that of a single pier. Moreover, the score depth of downstream piers, which are less than that of a single pier, increases with increasing S/d. The compressed (HSV) arms affect the local scour depth significantly if piers are staggered and S/d $\le$ 5. In this range of S/d, the HSV arms are intensified, resulting in a deeper scour hole. However, this effect also becomes insignificant with increasing S/d. The data obtained for each pier group were analysed, using a multiple regression model, to develop local scour depth prediction equations for the front, middle, and rear piers. The regression model includes two important dimensionless parameters ($\beta$ and S/d) associated with group effects, as regressors. The proposed prediction equations estimated the observed data and similar-type published data reasonably well, within marginal errors. From a general practical view-point, the number of prediction equations was reduced to two equations for all pier groups: one for the front piers and the second one for the downstream piers (i.e. combined middle and rear piers).

Download or read book The Impact of Ice Conditions on Local Scour Around Bridge Piers written by Faye Hirshfield and published by . This book was released on 2015 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Ice cover imposes an additional boundary layer on a river channel and can influence sediment transport around bridge structures. The main objective of this study was to gain a better understanding of how ice cover is related to local scour around bridge piers. A set of flume experiments were completed investigating local scour around bridge piers under open channel, smooth ice and rough ice cover conditions. Three different non-uniform sediments were used with D50??2019?s of 0.47, 0.50 and 0.58 mm. The location of the average maximum velocity under rough ice cover ranged from 0.36-0.43H and for smooth cover was 0.41H, with depth (H) measured from the channel bed to water surface. Turbulent intensity was greater under ice cover than open channel conditions. Local pier scour under rough and smooth ice cover was on average 37 and 20 percent greater than open channel scour depth respectively. The maximum scour depth always occurred at the pier face. Greater pier scour under ice cover is related to larger streamwise and downward flow velocities at the pier face under rough ice cover. The scour hole velocity for rough and smooth ice cover was 33 and 15 percent greater than open channel scour hole velocity respectively. Under all channel covers an armour layer formed in the scour hole. For all experiments, as the armour layer size increased, the maximum local scour depth decreased. A critical assessment of current bridge research and construction was also conducted in order to address how this study contributes to modern day bridge design. It was found that this study addresses current knowledge gaps in bridge manual used in North America. Specifically, study results concerning scour hole depth under ice cover and scour hole flow fields under ice cover are important contributions to the field of bridge hydraulics."--Leaf ii.