Precasteel Makes Maiden Voyage at LaGuardia Airport
By Brian M. Fraley
Bringing a new product to market is never an easy task, especially when it is being supplied to a large joint venture working on a high- profile project like the $8-billion Central Terminal Replacement Proj - ect at New York’s LaGuardia Airport. Walsh Construction and Skanska USA, operating as the Design-Build Joint Venture of Skanska-Walsh on this project for the Port Authority of New York and New Jersey (PA - NYNJ), decided to put Stay-In-Place-Fascia-Forms (SIPFF) to work on two bridges that carry vehicular traffic between terminals. Addressing the “Rusting of America” This precast fascia form was patented by Precasteel LLC of Skillman, New Jersey. It is essentially an L-shaped piece of precast concrete de - signed to stay in place and serve as a form for the bridge deck pour and subsequent barrier pour. Precasteel is the brainchild of Gary M. Din - more, P.E. It was conceived based on a trend he noticed over the course of 20 years working on numerous New York City bridge projects with bridge bracket and conventional overhang construction issues. Dinmore recalled learning about the graying of America – caused by the aging of the Baby Boomers – during a Penn State Economics class. He didn’t recognize the significance of this trend at the time and the window of opportunity eventually closed. Despite the missed opportu - nity it left him looking for another trend, which he discovered while inspecting bridges early in his career. “Rather than the graying of America,” Dinmore recalls, “I started thinking of the rusting of America and the fact that our bridges are getting old and need to be replaced.” Recognizing that the seemingly endless inventory of bridges would eventually have to be fixed, especially those built in the post-World War II era, he set out to identify market inefficiencies. Dinmore found what he was looking for in bridge overhang brackets. During his deployment to Lebanon as a member of a Special Forces ‘A’ Detachment, he saw stone aqueducts dating back to the B.C. era with overhangs reportedly constructed in a similar manner with timber falsework for support. He believed there had to be a better way because of advancements in modern materials where concrete can nearly mimic the strength of mild steel; hence the name PRECASTEEL®. Barriers Cleared at LaGuardia Design work at LaGuardia was done in 2018, but construction unfolded in 2019. Precasteel had done research and development and built proto - types and full-scale mock-ups in the past, but this was the first actual job. “This is the first production job on a permanent structure,” says Dinmore. “It was probably the hardest project we could have asked to start with.” There could be no production mistakes on a project of this magnitude.
Precasteel had to slip form a full-scale mock-up at the Lehighton, Pa. facility of its precast supplier, J&R Slaw. It also had to clear the design review process under the scrutiny of WSP USA and HOK. LaGuardia was challenging on several levels. It was a large project requiring approximately 1,800 linear feet of SIPFF panels for two structures, each with nine 100-foot spans of varying soffit widths and two spans with curvature. It also required a deviation from the standard shape. The architect wanted a “Lazy L” shape for aesthetic reasons. The placement of light blisters also required the soffits to be bumped out from 30 to 44 inches. The fact that one bridge used prestress con - crete Bulb T Beams and the other steel girders wide flange beams also required Precasteel to modify hardware during the project to accom - modate the geometry of the two different bridge beam types. The Precasteel design allowed for a ¼-inch gap between panels to pro - vide some construction tolerances since no closure pours were allowed on the structures to avoid contrasts in color. It also helped with the camber, which is essentially the upward deflection built into the bridge beam during fabrication. The camber was necessary for the structure to lay level after the entire deadload was applied. Dinmore confirmed that the gap closed and the panels settled into position along the beams’ edge without consequence when Skanska-Walsh poured the deck. “Everything behaved the way we anticipated,” he says. “The ¼-inch gap gave them a lot of leeway in the field.” One unexpected benefit was that the gap was hidden in the shadows of the chamfered edges upon completion, which made the façade even more aesthetically pleasing. Walsh Construction and Skanska USA, operating as the Design-Build Joint Venture of Skanska-Walsh on this project for the Port Authority of New York and New Jersey (PANYNJ), decided to put Stay-In-Place-Fascia-Forms (SIPFF) to work on two bridges that carry vehicular traffic between terminals.
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January 2023 csengineermag.com
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