N.Y.’s crumbling Tappan Zee Bridge will give way to a new span with the help of Gerdau
December 2013 - At 16,013 feet long, the Tappan Zee Bridge, carrying interstates I-87 and I-287 over the Hudson River at one of its widest points, is the longest bridge in New York state. It’s a massive, seven-lane span with a graying steel cantilever structure—just one indicator of its age: This month marks 58 years since it opened in 1955.
It’s among the many aging bridges in the U.S. that have outlived their intended lifespans. Crumbling concrete, rusty steel and weight-reducing lane closures reveal decrepit conditions, which can be catastrophic if unaddressed. The Tappan Zee Bridge is about 10 years older than the I-35W bridge in Minneapolis, which tragically collapsed in 2007 due to a failed steel gusset plate. The collapse caused a flurry of inspectors to assess the country’s worn-out bridge infrastructure, bringing the problem into sharp focus. For that reason, the Tappan Zee Bridge has been called the “hold-your-breath-bridge.”
As the clock ticks for the Tappan Zee, which is a critical link in the northeast, work is underway to replace it. Connecting Tarrytown on the east shore to South Nyack on the west, the New NY Bridge is being built adjacent to the north of the Tappan Zee, with help from long steel producer Gerdau. The company will supply about 32,000 tons of concrete reinforcing steel for the twin cable-stayed dual-span bridge.
Gerdau is fabricating product ranging from No. 5 to No. 18 rebar, with the heavier bar accounting for a higher percentage of the weight, between two of its New Jersey facilities in Perth Amboy and Sayreville—the former facility is only about 50 miles from the construction site.
To date, the longest length required is 60 feet, says Greg Galante, the sales director for Gerdau’s Northeast region. “Our facilities in New Jersey have the capacity to produce, shear, bend and provide threading of all sizes and grades of reinforcing steel,” he says. “We also offer the epoxy coating of stock steel out of the Sayreville steel mill, which has a melt shop capacity of 800,000 tons annually.”
All the materials will be transported via tractor trailer and barge. Gerdau’s Perth Amboy plant is only about a quarter-mile from a 300-foot-long marine dock, a key shipping advantage in the project. From there, the trip to the construction site is only about 50 miles north.
The New NY Bridge is designed as a dual-span twin bridge with eight general traffic lanes, four emergency lanes and a dedicated commuter bus lane, plus a pedestrian/bike path. It’s expected to last 100 years. Because construction recently began after more than a decade of delay, much of the current work involves the more mundane but crucial work underwater: armoring of the dredge channel, installation of piles, and preassembling the reinforcement steel already onsite.
The bridge’s design and construction is being spearheaded by Tappan Zee Constructors, a consortium of Fluor Enterprises, American Bridge Co., Granite Construction Northeast, and Traylor Bros. According to the New York State Thruway Authority and State Department of Transportation, both of which administer the bridge, the first span is slated to open in 2016 and will be complete by 2018, at a cost of about $3.1 billion.
One of the largest suppliers of special long steel in the world, Gerdau has also provided steel for the Cooper River Bridge in Charleston, S.C.; the Sunshine Skyway Bridge carrying I-275 in Tampa Bay, Fla., and the new I-35 bridge in Minneapolis. In addition to Gerdau, Lancaster, Pa.-based High Steel recently announced it will supply steel for the approaches to the bridge.
Gerdau is known to recycle metal for bridge projects, however the Tappan Zee will remain open until the New NY Bridge is done. When TZC demolishes the old bridge, its steel is expected to be salvaged. “We look forward to being involved in this process,” says Galante. MM