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ACB armoring potential failure modes at dam embankments and spillways




Schweiger, Paul, author
Shaffer, Darin, author
Nadeau, Jim, author
Colorado State University. Department of Engineering, publisher

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Over the past 26 years numerous embankment dams and earth-cut spillways in the United States have been armored using Articulating Concrete Blocks (ACBs) to provide erosion protection. 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, some ACB overtopping applications have failed and others have experienced damage requiring maintenance to make the ACB system functional again. Much has been learned about what works and what does not work. Of the ACB installations that have failed or experienced damage, the underlying issues have been attributed to one of several potential failure modes that may not have been understood or adequately addressed during the design. The purpose of this paper is to share information on several recent ACB embankment armoring and spillway armoring failures, and to describe the specific failure modes associated with these incidents. Suggestions for incorporating design features to address these potential failure modes are also provided. This information is important for engineers to consider during their designs, and for regulators reviewing ACB armoring designs, so that future failures and unnecessary damage resulting in costly maintenance can be prevented.


Presented at the Protections 2016: 2nd international seminar on dam protection against overtopping: concrete dams, embankment dams, levees, tailings dams held on 7th-9th September, 2016, at Colorado State University in Fort Collins, Colorado, USA. The increasing demand for dam and levee safety and flood protection has motivated new research and advancements and a greater need for cost-effective measures in overtopping protection as a solution for overtopping concerns at levees and dams. This seminar will bring together leading experts from practice, research, development, and implementation for two days of knowledge exchange followed by a technical tour of the Colorado State University Hydraulic Laboratory with overtopping flume and wave simulator. This seminar will focus on: Critical issues related to levees and dams; New developments and advanced tools; Overtopping protection systems; System design and performance; Applications and innovative solutions; Case histories of overtopping events; Physical modeling techniques and recent studies; and Numerical modeling methods.
Includes bibliographical references.

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potential failure modes


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