Download or read book Streambed Stresses and Flow Around Bridge Piers written by and published by . This book was released on 1996 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Streambed Stresses and Flow Around Bridge Piers written by Arthur C. Parola and published by . This book was released on 2001-02-01 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scour of streambed material around bridge foundations by floodwaters is the leading cause of catastrophic bridge failure. This study defined streambed stresses around a full-scale bridge pier and compared that info. with streambed-stress data collected in the lab. on small-scale bridge piers. Both the magnitude and dist. of streambed stresses are compared for the full-scale and small-scale bridge piers. 2-dimensional velocity data were collected at 81 vertical locations around a cylindrical pier for 3 separate flow conditions. The velocity data was used to estimate streambed stresses. Contours of the stress data were produced for the full-scale bridge pier. Tables.

Download or read book Streambed Stresses and Flow Around Bridge Piers written by and published by . This book was released on 1996 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Water resources Investigations Report written by and published by . This book was released on 2002 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Water resources Investigations Report written by and published by . This book was released on 1996 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1997 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Publications of the U S Geological Survey written by and published by . This book was released on 1997 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Publications of the Geological Survey written by Geological Survey (U.S.) and published by . This book was released on 1997 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flow and Erosion Around Bridge Piers microform written by Ferdous Ahmed and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1995 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: The structure of the flow and erosion around circular cylinders were investigated experimentally. Smooth and sand bed runs (with and without scour holes) were performed to study the effect of roughness and scour holes on the flow. Detailed measurements of velocity, pressure, bed shear stress and scour profiles were made.

Download or read book River Coastal and Shoreline Protection written by C. R. Thorne and published by John Wiley & Sons. This book was released on 1995-07-05 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt: RIPRAP is a widely used engineering method for protecting river banks and coastlines from erosion. This book studies the fundamental issues and problems concerned with various aspects of this method of erosion control.

Download or read book Bed material Entrainment Potential Roaring Fork River at Basalt Colorado written by John Grant Elliott and published by . This book was released on 2002 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of Pier scour Equations for Coarse bed Streams written by Katherine J. Chase and published by . This book was released on 2004 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Streambed scour at bridge piers is among the leading causes of bridge failure in the United States. Several pier-scour equations have been developed to calculate potential scour depths at existing and proposed bridges. Because many pier-scour equations are based on data from laboratory flumes and from cohesionless silt- and sand-bottomed streams, they tend to overestimate scour for piers in coarse-bed materials. Several equations have been developed to incorporate the mitigating effects of large particle sizes on pier scour, but further investigations are needed to evaluate how accurately pier-scour depths calculated by these equations match measured field data. This report, prepared in cooperation with the Montana Department of Transportation, describes the evaluation of five pier-scour equations for coarse-bed streams. Pier-scour and associated bridge-geometry, bed-material, and streamflow measurement data at bridges over coarse-bed streams in Montana, Alaska, Maryland, Ohio, and Virginia were selected from the Bridge Scour Data Management System. Pier scour calculated using the Simplified Chinese equation, the Froehlich equation, the Froehlich design equation, the HEC-18/Jones equation and the HEC-18/Mueller equation for flood events with approximate recurrence intervals of less than 2 to 100 years were compared to 42 pier-scour measurements. Comparison of results showed that pier-scour depths calculated with the HEC-18/Mueller equation were seldom smaller than measured pier-scour depths. In addition, pier-scour depths calculated using the HEC-18/Mueller equation were closer to measured scour than for the other equations that did not underestimate pier scour. However, more data are needed from coarse-bed streams and from less frequent flood events to further evaluate pier-scour equations.

Download or read book Water resources Investigations Report written by John Grant Elliott and published by . This book was released on 2002 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Publications of the Geological Survey written by Geological Survey (U.S.) and published by . This book was released on 1997 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pier and Contraction Scour in Cohesive Soils written by J.-L. Briaud and published by Transportation Research Board. This book was released on 2004 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration."

Download or read book Field Observations and Evaluations of Streambed Scour at Bridges written by U. S. Department Of Transportation and published by CreateSpace. This book was released on 2015-03-12 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridge piers and highway embankments leading to a bridge often obstruct the flow of floodwaters, causing an increase in velocity and the development of vortices. The increased velocity and vortices often cause scour near the bridge foundations. The damage to and failure of bridges caused by scour are problems of national concern. This report describes the results of the second USGS national field-data collection and analysis study on scour at bridges, funded by FHWA. The database originally developed during the first national study has been enhanced and many scour measurements added, including measurements of abutment and contraction scour. Sufficient local pier scour data are now available to permit a detailed analysis of local pier scour. Scour depths computed from published pier scour equations are compared to the field measurements. Many commonly cited dimensionless variables believed to control the depth of scour are evaluated and compared with equations developed from laboratory data. The effect of the size and gradation of the bed material on the depth of scour is investigated, and a correction factor for the HEC-18 pier scour equation is proposed. Available data are insufficient to permit a detailed investigation of contraction and abutment scour; however, some basic comparisons and qualitative observations are presented on the basis of a review of the literature. The results of scour analyses for two contracted bridges are compared with real-time field data.

Download or read book Prediction of Turbulent Flow and Scour Around Bridge Piers written by Shaghayegh Pournazeri and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The prevention and control of bridge scour is a challenging element in bridge-pier foundation design. Sediment scour from around the piers has been a main cause of all bridge failures. For the cost-effective and reliable design of pier foundations, one needs accurate prediction of flow-inducing scour. Such prediction can be obtained from numerical modelling, as a good extension of experimental results. General CFD software packages are incapable to simulate sediment transport (bedload) and bed-level change (scour/deposition). Some numerical models have been developed for bedload and scour simulations, but there are two major limitations: (1) the bed sediments are assumed to have uniform grain size which is not true in natural river channels; (2) the modelling techniques are not computationally efficient for applications at the field scale. Thus, new modelling techniques for scour prediction are needed.The objectives of this research are: (1) to modify an existing shallow-water hydrodynamics model to allow for non-hydrostatic pressure corrections; (2) to improve the prediction of bed shear stress, a key parameter for bedload prediction; (3) to incorporate a new module for calculating bedload of mixed sediment-grain sizes; (4) to verify the model’s prediction with existing experimental data.For pressure corrections, a seven-diagonal linear system is added to the model, which is symmetric and positively defined. This system is numerically solved for non-hydrostatic pressure through preconditioned conjugate gradient iterations. Then, corrections to velocity and water surface elevation due to non-hydrostatic pressure are obtained. Fractional bedload calculations are based on a surface-based transport function, which depends on a particle-hiding factor, bed shear stress, and grain size distribution. Bed level change caused by bedload is calculated using the Exner equation added to the model.The new model successfully predicts 3-D velocities around a circular pier in a fixed scour-hole and scour development on a mobile bed with uniform and non-uniform sediments. We improve bed shear stress prediction by using near-bottom velocities, as opposed to the widely used bottom-layer velocity, in the wall function method. Velocity and scour depth predictions agree well with experimental data. We show that scour emerges from the lateral sides of a pier, and scour patterns move toward its upstream nose. On the upstream side, relative to the pier’s centre, scour depth increases until the bed slope reaches the angle of repose of sediments. On the downstream side, scour continues until equilibrium is reached. Scour is deeper on the upstream than downstream side. Non-uniformity in grain sizes tends to reduce the magnitude of scour. The presence of the pier causes a strong vortex at its foot on the upstream side, which effectively moves sediments toward downstream. On the upstream side, the scour-hole’s outer shape is almost half a cone, true for both uniform and non-uniform sediments. These findings have implications to foundation design. The modelling techniques presented in this study are computationally efficient and are practical for applications at the field scale, which have been difficult so far.