Current Best Design Practices Using Articulating Concrete Blocks (ACBs) in Super Critical Flow Conditions

Jim Nadeau, Product Specialist ACB's, Ferguson Waterworks

Christopher I Thornton P.E. PhD, Associate Professor Civil Engineering, Colorado State University

This presentation will cover a brief history of the technology development relating to ACB design and applications leading up to the current design guidance considered the best practice for the industry. The evolution of the Factor of Safety calculations (FOS) has evolved over the last 30 years, culminating in 2010 with the PhD dissertation of Amanda Cox. This method was adopted as part of NEH Part 628 Chapter 54 ACB Armored Spillways in March 2020. Part of Chapter 54 addresses the need to evaluate hydraulic jump stability of a given project for the design hydraulic conditions which was further outlined in a paper presented by the authors of this paper at the ASDSO National Conference in 2019 in Orlando Florida. We will discuss the new approach to ACB designs for both sub and super critical flow conditions as well as discuss continuing analysis on the topic of hydraulic jumps. These new design and project specification criteria have been adopted by the NRCS on a national level and by the USACE Jacksonville District. We are currently preparing and developing a standard test procedure within ASTM for determining hydraulic jump stability under super critical flow conditions.


Author Bio

Jim Nadeau – Brief Biography

• B.S. Chemical Engineering University of Maine
• M.S. Civil Engineering University of Maine
• MBA – University of Phoenix
• 11 years ACB Product Manager at ACF Environmental handling Sales, Marketing, Design and testing of ACB Systems
• 3 Years ACB Product Specialist Contech Construction Products handling Sales, Marketing and design of ACB Systems
• Currently Chairman of ASTM D18.25.04 ACB Subcommittee
• Personally involved in the design and installation of over 100 Dam Rehabilitation Projects involving ACB’s

Chris Thornton

PHD Colorado State University
Associate Professor Civil Engineering CSU Fort Collins
Director of the ERC Testing Lab at CSU
Tested over 80 systems for erosion control performance