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New Champlain Bridge designer Ted Zoli

In addition to being a designer of bridges, Zoli teaches bridge design at Columbia and at Princeton, from which he graduated in 1988.

"The Lake Champlain bridge set a high standard for any new bridge that replaces it; in some respects, it should be as important as the original," he says.

With the Lake Champlain Bridge, Zoli says, Spofford liberated the steel truss from its traditional function as a railroad bridge.

The 2,184-ft-long truss linking Crown Point and West Addison, Vermont is "nearly parabolic" in shape, continuous rather than segmented, and constructed with a "maximum navigational window" to permit steamboats to pass underneath.

Following construction of the bridge (for which Spofford was awarded a gold medal by the American Society of Civil Engineers in 1930, the year the bridge was completed), "hundreds of continuous truss bridges were built; it ushered in a whole new typology of bridge engineering," said Zoli.

Spofford, however, did not expect the bridge's piers to deteriorate as quickly as they did.

"We're not here designing a new bridge because of some flaws in the truss, but because of the piers," said Zoli. "Spofford used concrete containing tailings from local iron ore mines. When he tested the concrete at MIT, we surmise that he found it to be twice as strong as conventional concrete and concluded that the piers wouldn't require steel re-enforcement."

Time and ice took their toll on the piers, Zoli said. "Once the process of erosion starts, it's very difficult to stop. Once it gets going, it goes quickly."

After being found to be unsafe because of the condition of the piers, New York and Vermont decided to close the bridge in October.

In December, Zoli unveiled the designs for six possible bridges, any one of which could feasibly replace he old one.

The recommendation of a Public Advisory Committee chaired by Assemblywoman Teresa Sayward, as well as the favorite of the public, is a design for a bridge known as a Modified Network Tied Arch Bridge, a steel structure with an arch along the main span that evokes the appearance of Spofford's 1930 bridge.

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