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Louis N. Triandafilou - Senior Structural Engineer, Federal Highway Administration (FHWA)
Louis N. Triandafilou acts as a liaison between the FHWA and the composites industry. In addition to working with AASHTO’s subcommittee on bridges, he also attends and hosts a variety of conferences to keep FRPs in the forefront of bridge applications.
What states are the most prolific composite adopters?
We would consider West Virginia one of the leading states in implementing FRP composites, going back to the 1980s. Starting in the mid-1990s, Dr. Hota GangaRao has done research in helping the state get several projects built in many areas: deck sections, wrapping and pipe projects. We also worked with them to put out a handbook on FRP projects, which was distributed to states as well as transportation centers. Hota helps keep West Virginia in the forefront and recently hosted a workshop together with the state DOT to explore implementing composites from the rehabilitation aspect, more for strengthening structures and using FRP wrapping than anything else.
What do you see as a bigger opportunity for composites: repair and strengthening or new structure creation?
Right now, it seems like the most common use of composites we’re seeing nowadays is for strengthening and upgrading existing bridges that need repair or have been deteriorated. We’re also seeing more interest in the FRP rebar projects, which use composites instead of steel to reinforce bridges. The whole area of specifications has been key in this area, as it is with any new technology. Getting those specifications adopted by the AASHTO bridge group is a big step in mainstreaming FRP composites.
What other states are using composites?
New York, Ohio, and Maine are also prolific composites adopters. Ohio, in particular, has an ongoing initiative for building a composite bridge in each of its county and state districts. That would mean at least 100 projects. Other states, such as Louisiana, Oregon, Florida, Missouri, Virginia and Maryland have all done a couple of projects. A lot of these states are using composites to solve problems with de-icing salts or high humidity environments that lead to higher rates of corrosion.
What applications could incorporate more composites?
Bridge decks or superstructures, which would be a bridge without beams, are a big one. We had the Innovative Bridge Research and Construction (IBRC) program under the former highway bill T21, where states could submit proposals for projects to incorporate high-performance bridge materials. More than half the projects were FRP related and a lot of those were deck projects or superstructures. A lot of suppliers got involved, but since that program has ended without complete specifications as to the usage of composites in decks, there haven’t been as many deck projects underway. However, there is a specification in the works through the T6 committee. They received completed work done by three university people who put together a very extensive specification for testing and acceptance criteria for deck projects. It’s been in committee for a couple of years, but there needs to be a meeting of the minds between industry and state DOTs as far as completing that specification.
What are the issues between those two sides?
The industry feels that the state’s testing requirements are too stringent. I’m not aware specifically of what those objections are, but what we’ve been trying to do is get the two groups together and see what those issues are and what compromises can be made, if any.
Why did the IBRC program end?
The exact program terminated with the end of the T21 highway bill. The bill officially ended in 2003, but was extended for two years after that without official legislation. There were more projects during that time, but it has since evolved into a different program called the Innovative Bridge Research and Deployment (IBRD) program, which looked more at projects on a systems basis instead of just specific high-performance materials. They wanted to branch out into bridge modular sections, and the means of accelerating bridge construction. But the funds aren’t as high as the previous program, and are not entirely dedicated to bridge-type projects.
Can that industry/government cooperation happen?
Yes. If the technology is going to move forward, it does have to happen. I think people want that to happen, and we’re certainly in favor of that happening.
In your interactions, what common concerns do you hear from industry?
The big issue continues to be cost. The cost of these materials is high on a first-cost basis. It depends on the application; the rebar is higher as well as deck and superstructure applications. The costs have come down over the years to about 50 dollars per square foot, but that is still twice as expensive as a conventional concrete deck. That cost factor weighs heavily with agencies because I think they still look a lot at initial cost. The composites industry needs to show advantages on a life-cycle cost basis. That kind of long-term performance data is lacking. The oldest vehicular composite bridge is now 15 years old. It may be performing well, but there needs to be the assurance on its long-term performance.
Are there test methods to address that issue?
Dr. GangaRao has developed a deterioration test for the rebar that estimates a service life of 75 to 80 years. But the biggest problem area we see with these projects is not with the FRP deck itself, but the overlay material on top of the deck. In many cases, that material has become delaminated and is de-bonded from the FRP deck as a result. The overlay isn’t a large structural item, but it’s still an important maintenance item that must be dealt with.
How can composites companies improve their business techniques?
In addition to being cost-competitive and showing more evidence on the life-cycle factor, I don’t get the same sense that everyone in the industry is pulling together in one boat. When I think about concrete or steel, there are national associations that are umbrella groups to those materials. I don’t know if I see that same relationship on the composites side.
That association does exist, so what can ACMA do better?
They just need to make sure they are the voice speaking for all manufacturers of composites. Some of these systems are proprietary in nature. But even if they are, these formulas still need to be shared. The state DOTs need to know about engineering properties and design.
Is that a particular problem with the composites industry?
When it comes to actual projects, we need to have generic specifications. IBRC was a popular program with a lot of FRP projects. In that program, we specified a particular supplier to provide a deck for a project. We need to graduate from that and get into more generic specification of FRP deck sections and not get specific products worked into projects. That is something still happening with suppliers. They want to know where they can get their product specified instead of pulling for the common good.
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