Introduction to Armoring Embankment Dams and Earth-Cut Spillways with ACBs: Download

Over the past 23 years numerous embankment dams and earth-cut spillways in the United States have been armored with Articulating Concrete Blocks (ACBs) to provide overtopping protection and to extend the life of the structures.  With the current focus on evaluating and rehabilitating dams throughout the United States to pass increased design flows, the use of this construction technology has become popular.  As a result, some ACB manufacturers have made significant investments in research and development of their concrete block systems to evaluate and improve their performance for use on embankment dams and earth-cut spillways, provide design data for designers, and develop more economical embankment armoring solutions.  In addition to established ACB manufacturers, researchers from Colorado State University, the USDA Bureau of Reclamation and the U.S. Army Corps of Engineers have designed, tested, and patented ACB systems for use on embankment dams, spillways and channels. Several dams and spillways armored with ACBs have been overtopped and performed satisfactorily with overtopping flow depths and velocities approaching 4 feet and 30 feet per second, respectively. Over the same period, at least one known ACB overtopping application has failed.  Much has been learned about what works and what does not work.

This webinar will be presented in two parts.  In Part 1, Dr. Chris Thornton will focus on ACB theory and will provide a brief history of the origins of ACB systems, discuss their development, and summarize the physical model investigations that have been completed to date to assess the performance and stability of various ACB systems.  Dr. Thornton will also present the latest approach for analyzing and interpreting the test data for use in design applications.  In Part 2, Paul Schweiger will focus on ACB applications and provide a summary of the first applications of ACBs for dam embankment overtopping and spillway armoring, present performance information on ACB dam armoring projects that have experienced overtopping flows, and discuss lessons learned from these and other projects.

The purpose of this webinar is to provide practitioners with an introduction to the application of ACBs for use in armoring embankment dams and spillways.

Christopher I. Thornton, Ph.D., P.E.

Associate Professor, Director, Colorado State University

Dr. Chris Thornton is the Director of the Engineering Center and Hydraulics Laboratory at Colorado State University.  He received his PhD in Hydraulics at Colorado State University and is a registered Professional Engineer in the state of Colorado.  He has over 18 years of experience in conducting hydraulic model studies and has specialized in high energy, supercritical flow conditions and performing prototype performance tests on erosion control techniques.  Chris and his team have recently developed a wave overtopping simulator and are currently investigating the stability of dam and levee protective layers from the combined effects of wave and steady state overtopping.  Dr. Thornton teaches the Senior Design series for the graduating Civil and Environmental Engineering students and has authored and co-authored numerous papers and reports in the area of open channel hydraulics.

Paul G. Schweiger, P.E.

Vice President, Gannett Fleming, Inc.

Paul G. Schweiger, P.E., CFM is a Vice President of Gannett Fleming, Inc. and Manager of the Firm’s Dams and Hydraulics Section.  He has over 30 years of consulting engineering experience during which time he has worked on hundreds of dam projects providing the full range of dam engineering services.  Mr. Schweiger is a certified Failure Modes Analysis facilitator and a regular ASDSO Dam Owner Workshop instructor.  He has published over 50 technical papers and technical manuals, given many presentations on a wide range of dam engineering topics, and is a frequent speaker at national dam safety conferences and specialty technical seminars.  He has served on several dam safety committees and work groups including: the National Dam Safety Review Board, the NRCS Study Work Group to evaluate design tools for roller-compacted concrete stepped spillways and embankment armoring, and the FEMA work group for establishing guidelines for the hydraulic safety of dams. He is currently serving as an expert hydrology and hydraulics engineer on an Independent External Peer Review panel for several United States Army Corps of Engineers DSAC I dam projects and managing the FEMA study to convey lessons learned from dam failures and incidents.  Paul is also currently serving on the Board of Consultants for the Oroville Dam Spillway Emergency Project.


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