By Bob Whitmore
Underground infrastructure projects at airports will get a lot easier for precasters to bid after the release of the new 717-page Approved Advisory Circular Specifications for 2019 published by the Federal Aviation Administration. The new circular specifies precast concrete for all underground drainage structures for the first time. It is the result of three years of collaboration between FAA and NPCA, and specifically mentions the NPCA Plant Certification Program (or equivalent) as the required QA/QC component for FAA projects that include precast structures.
The new specification, now in effect, comes on the heels of last fall’s 5-year Congressional reauthorization of the Federal Aviation Act, which earmarks $96.7 billion for aviation, a portion of which will go to infrastructure improvements at airports across the United States. The new FAA specification is mandatory for the more than 19,000 airport authorities under FAA jurisdiction and projects funded under the Airport Improvement Program.
“This is an important specification upgrade for the precast concrete industry,” said Ty Gable, president of the National Precast Concrete Association. “The old FAA spec did not mention precast concrete and was not up to date on materials such as self-consolidating concrete and some commonly used admixtures. We worked closely with the FAA to align the specification with the appropriate ASTMs.
“The result is that precast concrete is now specified for underground drainage structures and there is a clear distinction between precast and poured-in-place concrete.”
While precast producers were able to acquire FAA work under the old specification, in most cases they would have to persuade the local project engineers of the benefits of converting the job from poured-in-place to precast.
“Now, it’s in the spec,” Gable said. “It should be much easier to bid on FAA work without having to go through a complicated conversion discussion.”
The NPCA certification requirement also aligns the new FAA specification with the U.S. Department of Defense certification requirement in the Unified Facilities Guide Specification.
It started with a phone call
It all started with a phone call to Rich Krolewski, NPCA director of certification and regulatory services, from Buzz Morgan, general manager at Lindsay Precast’s plant in Alachua, Fla. Morgan was wondering if it would be possible to get newer technology such as SCC and admixtures recognized as viable materials for FAA work.
“We had been fairly successful at submitting and getting approved on precast designs, but we were constantly getting rejected on the use of SCC,” Morgan said. “The specifications were old, had not been updated in many years and anyone we tried to work with at a local level was not willing to vary away from the written specs. Because the spec didn’t allow for the use of SCC, the cost was higher due to the labor-intensive nature of pouring.”
It’s a situation that Morgan was finding with multiple bids.
“We were bidding electrical manholes on multiple different projects over the years from Atlanta to South Florida,” he said. “We were looking for help in getting the specifications updated, which governed all jobs. I believe they were still referring to specs written in 1985, but worse was they did not allow for high-range water reducers or even allow for flowable concrete admixtures.”
After hearing Morgan’s issues, Krolewski met in Washington, D.C., with John Dermody, FAA director of Airport Safety and Standards, and described the advantages of updating FAA specifications to align with ASTM standards. After receiving approvals from Dermody, Krolewski met repeatedly over the next three years with Greg Cline, FAA’s senior pavement engineer, to create the language in the document. When Cline met Krolewski, he was just starting to review the FAA specification and did not know that precast manufacturers were encountering barriers bidding on jobs.
“We appreciated the initial contact and the support Rich and NPCA provided in updating the advisory circular,” Cline said. “I believe in coordination with industry through the updating process, which is how I’ve always accomplished such efforts throughout my career.”
Gene Martin, president of Terre Hill Concrete Products, said his company has done a variety of work at airports over the years, but the specifics of airport construction and converting jobs to precast has its challenges.
“It hasn’t been impossible to get, but typically the specifications are pretty tough,” Martin said.
The requirements to account for heavy wheel loads call for structures with thick walls, which means very heavy pieces when you are converting a utility vault specified as cast-in-place to precast, for example. That’s where a specification change might help.
“If you could take something that was designed at 4,000 or 5,000 psi and do it with 6,000 or 7,000 psi and be able to reduce the wall thicknesses and possibly the reinforcing steel, it would be a lot better from the precasting standpoint,” Martin said.
Terre Hill Concrete won a Creative Use of Precast Award from NPCA in 2014 for converting a job at Baltimore-Washington International Airport to precast. Martin’s team manufactured a series of trench drains, manholes, vaults and leveling pads to create a drainage system that BWI uses in glycol reclamation for aircraft de-icing. The vaults weighed in at about 167,000 pounds each. The beauty of the project is that it was completed in three weeks with precast providing the ideal solution for minimal disruption and speedy installation.
“All of those structures were designed as cast-in-place,” Martin said. “What we did was basically broke them up into sections so they could be precast. However, they did not let us make exceptions to the wall thicknesses and the rebar and concrete strengths and we did not use SCC.”
With the new spec in place, jobs like this will be designed with precast from the start. And, Terre Hill already has a track record with airport work.
“I’d like to feel that we at least cracked the door open,” Martin said. “I think the precast projects that were done were very successful, but certainly being able to upgrade to things like SCC is going to be a real benefit.”
The other benefit is the status that comes with precast concrete being required in the specification along with the added QA/QC component of NPCA plant certification.
“We’re obviously not working with any direct representatives of FAA,” Martin said. “For the most part, we’re working with consulting engineers who do the design work. Having your foot in the door at a level above the design engineer is certainly where you want to be.”
Overnight, with minimal disruption While most precast work at airports came through converting poured-in-place structures under the old spec, in the case of Bartow Precast, airport engineers knew right at the start that precast was the best solution for installing grease interceptors. They approached Bartow several years ago during an expansion of Hartsfield-Jackson Atlanta International Airport, which bills itself as the busiest airport in the world. Bartow’s experience illustrates the advantages of using precast for airport construction projects.
“During their expansion they were bringing on a lot of new restaurants and they needed grease interceptors,” said Michael Tidwell, Bartow’s president.
Because of the need for quick, overnight installation with minimal disruption, there was no way the grease interceptors could be cast-in-place. Bartow’s team worked with engineers, to create a new spec for the project.
“With help from engineers, we designed and built a 1,500-gallon grease interceptors for them and delivered it to comply with their strict requirements, and it just kind of grew from there,” Tidwell said. “Every time they added a new restaurant, they contacted us.”
Precast made it much easier than casting in place.
“The complication is, number one, getting on the property with security clearances and then, number two, the timing,” Tidwell said. “It’s not like they can just close down a terminal. So, we were doing them at night, and more than anything we had to be quick.
“That’s where precast was the real winner over cast-in-place. We would have everything staged. They would open up the runway and escort us in. We would use our crane trucks to set the grease interceptors in the excavation and then we’d get out of there. The contractor would work all night to get ready for the next day.”
As a former NPCA Chairman of the Board, Tidwell has a broad perspective of the updated FAA specification. While precasters across the country will benefit from the new opportunities to bid airport work, he feels the real beneficiary is the airport authority.
“The ability to turn product quickly is key to them,” he said. “Cleanliness is also important, I’ve been told by contractors, because they don’t want debris around runways. It’s just a precise, quick turnaround.
“All the benefits of precast – building an engineered product in a controlled environment – go hand-in-hand with that application.”
Morgan said the new pro-precast stance should enhance the bidding process.
“We could bid jobs, we just could not take full advantage of our precast designs due to the outdated specs,” he said. “We just could not bid as aggressively as we normally would because of them not recognizing new technology.”
The addition of the NPCA plant certification requirement should pay dividends for precasters and the FAA, Morgan said.
“That change will certainly have a positive impact on those of us that bid FAA and DOD projects by using the everyday technology at our hands,” he said. “The quality should improve and that should help continue to improve the reputation of the NPCA and precast in general.”
For Cline, the 3-year process took longer than expected, but was worth the effort.
“We made it through with a great update to our FAA specifications and it also provided FAA with a great working relationship,” he said. “This supports the concept that government and industry should – and do – work together.”
Bob Whitmore is NPCA’s vice president of communication and public affairs.