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 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 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Pier Scour Equations for Coarse Bed Streams U S Geological Survey Scientific Investigations Report 2004 5111 2004 written by and published by . This book was released on 2004* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book EVALUATION OF PIER SCOUR EQUATIONS FOR COARSE BED STREAMS SCIENTIFIC INVESTIGATIONS REPORT 2004 5111 U S DEPARTMENT OF THE INTERIOR written by and published by . This book was released on 2004* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Pier Scour in Coarse Bed Streams in Montana 2001 Through 2007 written by U.S. Department of the Interior and published by CreateSpace. This book was released on 2014-07-23 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Determination of pier-scour potential is an important consideration in the hydraulic analysis and design of highway bridges that cross streams, rivers, and other waterways in the United States. A primary goal of ongoing research in the field of bridge scour is to improve scour-prediction equations so that pier-scour depth is neither underpredicted nor excessively overpredicted. Scour depth for piers in noncohesive, non-uniform streambeds with a mixture of sand, gravel, cobbles, and boulders (coarse-bed streams) generally is less than the scour depth in finer-grained (mostly sand) streambeds under similar hydraulic conditions. The difference in scour depth is attributed to formation of an armor layer.
Download or read book Updating HEC 18 Pier Scour Equations for Noncohesive Soils written by Haoyin Shan and published by . This book was released on 2016 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: A dataset of 594 bridge pier scour observations from two laboratory and three field studies was compiled. The dataset served as the testing ground for evaluating potential enhancements to the pier scour tools for noncohesive soils in Hydraulic Engineering Circular 18 (HEC-18). In the current (fifth) edition of HEC-18, there are two primary equations for pier scour in noncohesive soils. One is the general equation applicable to most situations, including clear water and live bed conditions. The second is a coarse bed material equation recommended only for use under clear water conditions with coarse bed materials. The objective of this research was to determine if the coarse bed materials equation could be used for conditions beyond those under which it is currently limited. A framework for evaluating the two equations was developed using qualitative and quantitative tools. The coarse bed equation is referred to as the Hager number/gradation coefficient (HN/GC) equation because it references the use of both in the equation formulation. After adjusting the HN/GC equation to a target reliability index of 2.0, it was evaluated on its ability to predict scour for a wide range of conditions in noncohesive soils. Partitioned subsets of the data based on key conditions—including the HEC-18 coarse bed criteria, clear water versus live bed transport conditions, gradation, and median grain size—were used for the evaluation. The equation performed reasonably consistently in all partitioned datasets, leading to the conclusion that it may be used for a broader range of conditions. A subgroup of pier group scour observations was assessed to determine if the equation could also be used for pier groups. The equation performed better for single piers but offered a basis for predicting local scour at pier groups.
Download or read book Method for Rapid Estimation of Scour at Highway Bridges Based on Limited Site Data written by Steven R. Holnbeck and published by . This book was released on 1997 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific Investigations Report written by and published by . This book was released on 2004 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Pier scour Measurement Methods and Pier scour Predictions with Observed Scour Measurements at Selected Bridge Sites in New Hampshire 1995 98 written by Erick M. Boehmler and published by . This book was released on 2000 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pier Scour in Clear water Conditions with Non uniform Bed Materials written by and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Pier scour design in the United States is currently accomplished through application of the Colorado State University (CSU) equation. Since the Federal Highway Administration recommended the CSU equation in 2001, substantial advances have been made in the understanding of pier scour processes. This report explains a new formulation for describing scour processes and proposes a new equation for pier scour design. A critical review of selected studies is summarized. A simplified scour mechanism is proposed in terms of a pressure gradient resulting from the flowstructure, flow-sediment, and sediment-structure interactions. An equilibrium scour depth equation is proposed based on this understanding of the scour mechanism and is validated and refined by a combination of laboratory and field data. The proposed equation is primarily applicable to clear-water scour conditions with non-uniform coarse bed materials."--Technical report documentation page
Download or read book Scour and Erosion written by Susan Burns and published by . This book was released on 2014 with total page 1152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pier Scour Equations Used in the People s Republic of China written by United States. Federal Highway Administration. Office of Technology Applications and published by . This book was released on 1993 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stream Stability and Scour at Highway Bridges written by Everett V. Richardson and published by ASCE Publications. This book was released on 1999-01-01 with total page 1076 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sponsored by the Water Resources Engineering (Hydraulics) Divsion of ASCE. This collection contains 75 papers and 321 abstracts presented at conferences sponsored by the Water Resources Engineering (Hydraulics) Division of ASCE from 1991 through 1998. The collection contains many new and expanded versions of the original papers and is designed to assist the practitioner with the concepts in evaluating stream instability and scour at bridges. Topics include: history of bridge scour research; bridge scour determination; stream stability and geomorphology; construction scour; instrumentation for measuring and monitoring; field measurement; computer and physical modeling of bridge scour; scour at culverts; and economic and risk analysis. One important paper contains 384 field measurements of local scour at piers made by the U.S. Geological Survey.
Download or read book Field Observations and Evaluations of Streambed Scour at Bridges written by and published by . This book was released on 2005 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The variability and complexity of site conditions make it difficult to develop methodology for predicting scour at bridges. Laboratory investigations often oversimplify or ignore many complexities common in the field. The U.S. Geological Survey, in cooperation with the Federal Highway Administration and many State highway agencies, has collected and compiled field data on scour at bridges at 79 sites located in 17 States. These data have been analyzed to isolate pier scour, contraction scour, and abutment scour. The national data base contains 493 local pier scour measurements, 18 contraction scour measurements, and 12 abutment scour measurements. The pier scour measurements were used to evaluate 26 published pier scour equations.
Download or read book Bridge Scour in Nonuniform Sediment Mixtures and in Cohesive Materials written by U. S. Department Of Transportation and published by CreateSpace. This book was released on 2015-03-12 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the summary and synthesis of the various components of the experimental study entitled "Effects of Gradation and Cohesion on Bridge Scour" conducted at Colorado State University between the dates 1991 through 1996. As a result of this effort, in excess of 250 new pier scour data was collected and a new equation was developed expressing pier scour in terms of the dimensionless excess velocity factor, flow depth, pier diameter and a correction factor for the coarse fractions present in mixtures was derived. The new method was tested with available data from previous research. This equation shows that gradation effects are not constant through the entire range of flow conditions but vary with flow intensity. Additionally, a new method to adjust FHWA's Colorado State University pier scour equation for initiation of motion and sediment size was developed. Abutment scour experiments resulted in over 384 new points and 2 new abutment scour equations. The first equation was derived from a 0.1 mm uniform sand mixture and defines an envelope relationship. The second equation applies to mixtures with coarse fractions. A coarse size fraction compensation factor Wg is presented to account for the presence of varying amounts of coarse material in sediment mixtures under different dimensionless flow intensities. These new equations represented the experimental data accurately but have not been tested with field data. Effects of cohesion on pier and abutment scour were studied systematically, and in excess of 200 new data points were collected covering a range of flow and cohesive parameter values. Relationships were developed to explain the variability of bridge scour in cohesive materials for various cohesive material properties.
Download or read book Stream Restoration in Dynamic Fluvial Systems written by Andrew Simon and published by John Wiley & Sons. This book was released on 2013-05-08 with total page 939 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 194. Stream Restoration in Dynamic Fluvial Systems: Scientific Approaches, Analyses, and Tools brings together leading contributors in stream restoration science to provide comprehensive consideration of process-based approaches, tools, and applications of techniques useful for the implementation of sustainable restoration strategies. Stream restoration is a catchall term for modifications to streams and adjacent riparian zones undertaken to improve geomorphic and/or ecologic function, structure, and integrity of river corridors, and it has become a multibillion dollar industry. A vigorous debate currently exists in research and professional communities regarding the approaches, applications, and tools most effective in designing, implementing, and assessing stream restoration strategies given a multitude of goals, objectives, stakeholders, and boundary conditions. More importantly, stream restoration as a research-oriented academic discipline is, at present, lagging stream restoration as a rapidly evolving, practitioner-centric endeavor. The volume addresses these main areas: concepts in stream restoration, river mechanics and the use of hydraulic structures, modeling in restoration design, ecology, ecologic indices, and habitat, geomorphic approaches to stream and watershed management, and sediment considerations in stream restoration. Stream Restoration in Dynamic Fluvial Systems will appeal to scholars, professionals, and government agency and institute researchers involved in examining river flow processes, river channel changes and improvements, watershed processes, and landscape systematics.
Download or read book 2005 Model Drainage Manual written by and published by AASHTO. This book was released on with total page 1410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
