With 200 piles—out of more than 1,000—now driven into the Hudson River, it's possible to envision the path of the twin spans that will form the New New York Bridge.
After all the preparatory construction, work on the actual bridge has begun in the Tappan Zee.
"You can start to see the outline," said Brian Conybeare, Special Advisor for the Tappan Zee Bridge, pointing out—to a boatload of journalists touring the massive construction site June 5—piles already in place between Westchester and Rockland.
At this point, both main span tower piles have been installed and are being cleaned out. (The piles are hollow pipe. Driven empty, they fill with river muck. Cranes with special claws then excavate that dirt so the piles can be cleaned out and filled with concrete and reinforced steel.)
The contractor is prepping and installing piles at four locations simultaneously.
Groups of piles form the piers. There will be only 43 approach span piers, compared to 196 on the existing bridge.
"Visually it's going to be a real change," said Dan Weiller, director of communication for the Thruway Authority, waving at the close-set, chunky piers of the Tappan Zee Bridge's long, low approach to Rockland County.
Piles are driven, cleaned, filled, then piers encapsulate groups of piles (five piers are now in place), columns rise from the piers, roadbeds hang from the towers—to see how the whole construction project flows, check out the animated YouTube video created for the New NY Bridge website.
Pile-driving close to shore on each side is being done not from barges but from temporary structures called the Rockland and Westchester trestles, said Larry Owen, deputy project manager. They're temporary work bridges from which to drive piles and build piers to prevent dredging close to shore—which could have hurt the Hudson River, undermined the banks and troubled the railroad tracks.