The 3.1 mile twin span cable-stayed bridge is the single largest bridge construction project in New York’s history.
Lohud.com reports it takes 1,000-plus workers, massive cranes, thousands of tons of steel and nearly 200 cables – making the new Tappan Zee Bridge a massive, complicated and fascinating project.
Much of the work building the new bridge is happening on the Hudson.
During peak construction hours, the Tappan Zee Constructors, the consortium of contractors tasked with designing and building the bridge, has more than 30 floating cranes on the Hudson River with four tower cranes plus the “I Lift NY” super crane, capable of lifting nearly 2,000 tons — or 4,000,000 pounds.
The I Lift NY crane, also known as the Left Coast Lifter, is responsible for the heaviest lifts. The rest of the cranes provide support, raising steel reinforcements and moving construction equipment. The barges, of which there are dozens according to the Thruway Authority, hold that equipment while out on the water.
Behind all that work are roughly 1,100 people, from heavy machinery operators to seamen to all manner of construction workers. Work goes on practically 24/7.
The 419-foot towers on the bridge’s main span will be its most striking feature. Right now, they’re still a work in progress.
Construction started in September, and ever since, the towers have been rising steadily thanks to the jump forms — the big blue boxes sitting on top of each of the eight towers.
The 650-square-foot jump forms are made up of two portions, interior and exterior. The exterior portion rises first, ahead of the interior portion. Then rebar is installed and the interior portion raised and concrete poured.
The process will be repeated until the towers are complete.
The Tappan Zee Bridge will be a cable-stayed bridge. The cables will be hung from the towers and support the girders and road deck. They’ll start going in this month.
The 192 cables, totaling 14 miles in length, will be mounted to plates in each of the eight towers, as well as the girders. The cables will directly support the girders and the road deck that sits on top of them.
Similar to a suspension bridge, which uses a series of primary and secondary cables to support the road deck, a cable-stayed bridge uses cables directly connected to the towers for support.
While the towers and cables will give the bridge its look, it’s the girders and road deck that will make up the actual bridge: the thoroughfare by which residents cross the Hudson River.
The girders, the big blue chunks of steel crews have been installing at a steady clip with the help of the 30 story tall I Lift NY super crane, are as long as 410 feet and weigh as much as 1,100 tons. They will support the road deck, which is being installed on the Rockland side of the bridge.
When both the Rockland-bound and Westchester-bound spans are finished in 2018, a total of 134 girders will be installed.
Materials for the girders are made in Virginia, North Carolina and Pennsylvania, and shipped to the Port of Coeymans, approximately 13 miles south of Albany, where they are assembled. Then, the girders are floated 95 nautical miles to the work site on a trip that takes 20 hours.