Paerdegat Basin Bridge

The City of New York ers, as well as super-elevation of uses High Performance the roadway around curves and realignment of the approaches to each bridge to improve sightlines. This work, along with of a massive overhaul of improvements to drainage on the the Belt Parkway. bridges, is designed to reduce - Parkway opened in 1941, its hance bicycle and pedestrian ac- cess and restore some historical vehicles per day. Since then, with character to the Robert Moses- the opening of JFK International era route with new landscap- Airport, the growth of suburban ing, railings, lighting, and stone communities on Long Island, and elements. (The entire Parkway construction of the Verrazano- award in 2006 from the NYC dramatically increased on the Art Commission.) parkway, which now sees nearly - 150,000 vehicles each day. Time bridge spanning Paerdegat on the seven bridges serving the parkway, many of which re- was assigned to NYCDOT’s In- ceived poor ratings in biennial House Design (IHD) team. Due inspections by the New York to damage to one of its twelve State Department of Transporta- cast-in-place concrete bents and tion (NYSDOT) in the past years. to long-term structural deteriora- In 2009, after determining that tion of its primary members and replacement of the aging struc- concrete deck, the Paerdegat bridge has been under continuous monitoring and a 5-ton weight the New York City Department restriction since September 2004. of Transportation (NYCDOT) Still, nearly 150,000 vehicles use began their extensive recon- the 70-year-old structure daily, The view inside one of the eastbound many on their way to JFK, so bridge’s box girders. involves instituting wider lanes, safety shoulders, median barri-

36 Metals in Construction Spring 2012 Paerdegat Basin Bridge 37 Right Box beams constructed with eastbound bridge are lifted into place. Below A worker from steel erector Northeast Structural Steel.

longer spans, the team had to raise the roadway elevation by behind the bridge’s new abut- ments to achieve this, the approaches to the bridge were preloaded with surcharge and equipped with weep drains to resolve the settlement of organic soil layers. Seismic isolation bear- ings distribute forces on the bridge’s substructure. Eliminat- smoother driving surface, but also decreased the likelihood of leaks and deterioration in the future. In addition to a design that will withstand the test of endur- ance faced by all NYC bridges and improve conditions for drivers, the southern structure also makes the crossing easier for pedestri- ans and bicyclists. They will have a dedicated path separated from the bridge and by a 15-foot-wide grass mall on the roadway. With less than half the number of piers, the size of the navigation channel beneath the bridge has also been increased, a boon to those who prefer to travel by boat. mention one that will serve most of the city’s population at during peak hours and allow pe- bridges. Although HPS has been Above one time or another and must destrian access at all times. used in hundreds of bridges with spans of 60, 80, and 90, 80 City’s history, the NYCDOT opted be erected over water, the bridge In order to accomplish this, elsewhere in the United States, and 60 meters in length. Due to for High Performance Steel (HPS) to required a high level of coor- construct the bridge’s box girders. NYCDOT needed to explore the new bridge’s curved shape dination between trades. “The building a six-lane bridge to one how it could take advantage and increased span lengths, both contractor and fabricator were side of the existing structure. east- and westbound designs instrumental in developing all However, limited right-of-way strength, durability or tried-and- incorporate three HPS 70W steel procedures from fabrication on either side of the old bridge true economical designs. Devel- trapezoidal box girders to resist - restricted them to a split design oped nearly two decades ago, torsion. Weighing more than 900 ing,” says Anil Vyas, deputy that alternated travel direction so HPS has become increasingly metric tons each, box beams that three lanes remained open for the eastbound bridge are 2.4 Engineering Review and Sup- the cost and weight savings it can meters deep, 3.6 meters wide port for NYCDOT’s Division of during the customary periods of provide. The material also resists at the top, and 370 meters long. - heavy volume. atmospheric corrosion, eliminat- DOT Fabrication Engineering Unit ing the need to coat steel bridges westbound bridge, at 2.5 meters stayed in close contact with the - in most environments. deep, 3.6 meters wide at the top steel subcontractors via weekly pal concerns. Durability of the Construction of the Paer- and 250 meters in length will technical teleconferences that structure was another, and the weigh approximately 600 metric solution to this represented one April 2011 with erection of a new - on schedule. eastbound bridge, south of the ference in length. Though the structural steel existing bridge. (The westbound In order to eliminate what the fabricator had experience in city’s history, High Performance bridge to the north is scheduled DOT called “substandard” sight fabricating tub girders of Grade Steel (HPS) with a yield strength for erection in the summer of distances on the original bridges

of 70 ksi was being used to build 2012.) The eastbound bridge was and accommodate the new, NYCDOT Division of Bridges; this page: Northeast Structural Steel Opening spread: Top: Northeast Structuralfabricating Steel; right: NYCDOT Division of Bridges a non-hybrid girder

38 Metals in Construction Spring 2012 Paerdegat Basin Bridge 39 Above The completed eastbound cross- consisting of Grade 70 HPS special procedures. Not only is a single Liebherr LR1400, 440 ing has less than half the number of Ton Crawler Crane, but certain piers as the older bridge, increasing the girder is a welded girder with Performance Steel’s reaction to maneuvers, including erection of size of the navigation channel beneath. heat from welding, it is also more the centermost girders, required and web. Though the bridge’s two cranes to work in tandem. - mill scale adheres more tightly Northeast also erected temporary tion plates are Grade 50 steel, its to the surface. For this reason, falsework supports to prop up Above The existing Paerdegat bridge girder structure is not consid- Grade 70 HPS web plates were individual tub girder segments (top) and renderings of the new east- and westbound crossings, scheduled for - between piers; once splices were PAERDEGAT BASIN BRIDGE completion in the summer of 2012. variety of steel grades used, with ers were welded on, in order to complete, these were removed. their varying thicknesses and Location: Belt Parkway, Brooklyn, NY associated welding processes, - Owner: NYCDOT Division of Bridges, New York, NY the fabricator performed a series ect’s subcontractors didn’t stop tidal wetlands of the Gateway Architects: NYCDOT Division of Bridges In-House Design, New York, NY of preliminary tests to ensure the at the fabrication shop; once National Recreation Area, mitiga- Structural Engineer: NYCDOT Division of Bridges In-House Design, New York, NY strength of each weld, identifying girders were trucked to the site, tion of environmental impacts Geotechnical Engineer: Earthtech, New York, NY the procedure for each weld detail structural steel erector North- has been and continues to be Environmental Engineer: AKRF, New York, NY on specialized shop drawings. east Structural Steel proposed Construction Management: NYCDOT Bureau of Bridge Capital Design and New York State’s Steel Construc- installation of temporary work once work is complete the new Construction, New York, NY tion Manual (NYS SCM) does not structures with their corrosion General Contractor: Tully/Posillico Joint Venture, Flushing, NY address HPS 70W, so welding bridge location in order to erect inhibiting coating will require Construction Program Management: GPI/CTE Joint Venture, New York, NY and fabrication were performed the steel over the water. The - Construction Support Services: URS Corp. in conjunction with NYCDOT in accordance with the AWS D1.5 materials used for erection of the In-House Design and Fabrication Engineering Unit of NYCDOT Quality - eastbound bridge will be recycled Assurance, New York, NY - and relocated to the north side Resident Engineer and Inspection Services: GPI/CTE Joint Venture, New York, NY cation with HPS 70W Steel. and a glimpse of the many Environmental Compliance: Environmental Engineering Unit of NYCDOT Quality The welding process pre- westbound roadway. Almost all of modernizations coming to the Assurance, New York, NY

sented other challenges requiring the erection was performed with NYCDOT Division of Bridges This spread: Structural Steel Erector: Northeast Structural Steel, Mt. Vernon, NY

40 Metals in Construction Spring 2012 Paerdegat Basin Bridge 41