The westbound towers of the new Tappan Zee Bridge will likely be completed within the next few weeks and the mysterious blue boxes atop each one will be gone, says the company building the towers.
The towers are reaching their ultimate height of 419 feet above the Hudson River, according to Tappan Zee Constructors.
After the final sections of the $4 billion spans towers are completed, TZC will remove the project’s “blue jump forms.”
The prominent blue boxes sit atop the towers, helping crews build them up with rebar and concrete vertically.
First the two frames of the jump box are secured to the tower segment.
Each form can take up to 650 square feet.
Their outsides go up first, providing a safe area for the work crews, and then steel rebar is installed. The interior part is raised and concrete is poured and then allowed to cure.
Once that’s done, a series of rails are raised to the next level to allow the external frame to rise by increments of between 12 and 18 feet.
That happens over and over until each tower is complete.
The workers use stairs and elevators on the sides of the towers, and catwalks, to access the jump forms.
Fall protection lines are installed around the forms for the workers’ safety.
The forms follow the “slight outward angle” of the towers as they rise, according to NewNYBridge.com.
The new bridge’s road deck and steel girders that support it are held up by cables.
Once the towers are two-thirds done, anchors for the cables will be installed.
The first part of the new bridge is scheduled to open a year from now. The entire span is projected to be completed by 2018.
Progress on the bridge can also be viewed from two riverside platforms in Nyack’s Memorial Park in Rockland County and in Tarrytown’s Scenic Hudson River Walk Park on the Westchester County side.
To follow the progress of the jump forms, visit NewNYBridge.com/Webcam .