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In this episode, we talk with Michael McDonagh, P.E., P.Eng., vice president and senior technical principal at WSP, about the exciting uses of ultra-high-performance concrete (UHPC) and the challenges and promising future of this groundbreaking material in structural engineering.
***The video version of this episode can be viewed here.***
Engineering Quotes:
Here Are Some of the Questions We Ask Michael:
- How did your experience as an engineer compare to focusing more specifically on design, including both the advantages and disadvantages you encountered?
- Could you explain what ultra-high-performance concrete (UHPC) is and how it differs from traditional concrete?
- Do steel fibers in UHPC only serve for shear resistance and crack reduction, or do they also increase tensile strength or have other purposes?
- Can you share project examples where you chose ultra-high-performance concrete based on its suitability for specific needs?
- Since UHPC is significantly more expensive than conventional concrete, how do you justify the higher costs associated with using it in projects?
- Aside from its longevity, how does ultra-high-performance concrete contribute to sustainability, and are there other sustainable aspects associated with it?
- Are there guidelines or frameworks available for engineers interested in using UHPC in their projects, and what do these typically involve?
- Was the absence of a design guide for structural engineers the main barrier preventing wider use of ultra-high-performance concrete in the industry, or were there other factors at play?
- Where do you think UHPC has untapped potential in terms of regions or types of structures?
- What final advice do you have for structural engineers or structural engineering students as they progress in their careers?
Here Are Some of the Key Points Discussed About Innovative Ways to Utilize UHPC in Construction:
- Focusing specifically on design, especially with ultra-high-performance concrete (UHPC), has allowed Michael to delve into innovative projects and hone expertise in a niche area. This shift brings advantages in creating intricate and visually appealing designs, but also presents challenges, like navigating complexities and costs associated with advanced materials in construction.
- UHPC differs from traditional concrete by excluding coarse aggregates and using fine sand with steel fibers for enhanced strength and durability. UHPC’s exceptional properties include extreme durability and resistance to permeability, making it ideal for applications requiring longevity and high performance.
- Ultra-high-performance concrete gains significant tensile strength from steel fibers, typically used in volumes ranging from 2% to 3%. The inclusion of these fibers provides both strength and ductility, allowing for innovative applications like thin, flexible UHPC slabs capable of substantial deflection without failure.
- UHPC has transformed bridge construction by strengthening connections between precast members, improving durability, and speeding up construction while reducing costs. UHPC overlays on aging bridge decks provide exceptional durability and stiffness, enhancing structural strength and longevity compared to traditional alternatives.
- Ultra-high-performance concrete can save costs in structural projects by optimizing designs and reducing the need for extra materials. While initial costs may not be lower, a lifecycle cost analysis often proves UHPC’s long-term cost-effectiveness, particularly for durability-focused owners.
- UHPC overlays provide significant long-term value, with durability projections of 30 to 50 years in lifecycle cost analyses. Although project data beyond 20 years is limited, UHPC’s proven durability indicates lasting benefits for infrastructure maintenance and longevity.
- Efforts to make UHPC cost-effective also promote sustainability by minimizing material use and maximizing durability. With strategic design, UHPC’s higher cement content can be offset, reducing carbon emissions and demonstrating long-term environmental benefits.
- Federal Highways has played a significant role in providing UHPC guidance, even though it’s not a code-producing entity. Recently, AASHTO published its first guide specification for structural design with UHPC, marking a major step toward broader acceptance and adoption of UHPC for structural applications in the industry.
- The absence of a structural design guide was a major obstacle to wider UHPC adoption. Many were deterred by the initial high material cost without realizing its potential for cost-effective applications once understood and implemented effectively.
- UHPC presents untapped potential in both new construction and rehabilitation projects. Bridge deck overlays using UHPC can significantly extend the service life of aging concrete structures like box girder bridges, avoiding costly replacements.
More Details in This Episode…
About the Guest: Michael McDonagh, P.E., P.Eng.
Michael McDonagh is a Vice President and Senior Technical Principal at WSP. He has over 27 years of experience in the field of bridge design and construction and is an expert on UHPC, a revolutionary construction material that can dramatically improve the service life and efficiency of structures. Since 2008, Michael has designed bridges and bridge rehabilitations using UHPC in many different applications. He has assisted the Federal Highway Administration from 2016 to 2020 and again from 2022 to 2023 to promote UHPC and help write and review UHPC design guidance. He is a member of ACI 239 and the organizing committee of the International Interactive Symposium on UHPC. Michael also served for two years as the Vice President of Engineering & Projects for a commercial producer of UHPC. Michael’s bridge design experience includes bridges located in Canada, France, the United Arab Emirates, and across the USA, with a wide variety of bridge types including multiple signature footbridges. Michael received his BS and MS in Civil Engineering from Penn State University.
About the Hosts
Mathew Picardal, P.E., SE
Mathew is a licensed engineer, practicing on structural projects in California, with an undergraduate degree from Cal Poly Pomona and an M.S. in Structural Engineering from UC San Diego. He has designed and managed various types of building structures, including residential wood apartment buildings, commercial steel buildings, and concrete parking structures and towers. He also hosts the new YouTube channel “Structural Engineering Life,” through which he promotes the structural engineering profession to engineering students who are not familiar with the industry perspective.
Rachel Holland, P.E.
Rachel is an experienced R&D engineer, developing and patenting multiple new structural connectors. She also offers her expertise to both the end user and specifiers as a branch engineering supervisor. She represents Simpson Strong-Tie as a deck expert, educating others on how to properly build code-compliant decks. Before her career working for a manufacturing company, she spent many years working for engineering consulting companies. She earned her Architectural Engineering undergrad degree from California Polytechnic State University, San Luis Obispo, and a Master of Business Administration (MBA) from California State University, Monterey Bay. Rachel is a licensed P.E. in California, Arizona, and New Mexico.
Sources/References:
WSP
Penn State University
Federal Highway Administration (FHWA)
Turner-Fairbanks Highway Research Lab (TFHRL)
Pulaski Skyway
Federal Highway Everyday Counts Program
International Interactive Symposium on UHPC
Rapid Chloride Penetration Test
Delaware Memorial Bridge
Latex Modified Concrete
Polyester Polymer Concrete
American Association of State Highway and Transportation Officials (AASHTO)
Precast/Prestressed Concrete Institute (PCI)
AASHTO Guide Specification for Structural Design with UHPC
PCI Design Guide for Precast Structural UHPC
American Society of Civil Engineers (ASCE)
FRP (Fiber-Reinforced Polymers)
Project Case Study – Rehabilitation of the Pulaski Skyway: ultra-High Performance Concrete Connections
Performance of Ultra-High-Performance Concrete in Harsh Marine Environment for 21 Years
Technote: Design and Construction of Field-Cast UHPC Connections
Design and Construction of UHPC-Based Bridge Preservation and Repair Solutions
Ultra-High Performance Concrete (UHPC) Overlays: An Example of Lifecycle Cost Analysis
Structural Design with Ultra-High Performance Concrete
Ultra-High Performance Concrete Is Advancing More Resilient U.S. Infrastructure
International Interactive Symposium on UHPC
Connect with Michael McDonagh, P.E., P.Eng., on LinkedIn
Please leave your comments or questions in the section below on how you utilize UHPC in construction.
To your success,
Mathew Picardal, P.E., SE, and Rachel Holland, P.E.
Hosts of The Structural Engineering Podcast
