Dangling Crane Was Weather-Vaned, Contractor Says
"There was enormous torque when this fell over, and the fact that those connectors withstood the pressure just testifies to how well they were put it [sic] and how stable that tower is," adds Mayor Michael Bloomberg in an ">Oct. 31 statement.
Contractors will have several options to remove the damaged rig, experts say. One would be to carry a portable derrick to the roof, which would then be used to build a larger derrick hoisted up from the ground.
The larger derrick would then help dismantle the damaged jib, which weighs between 40,000 and 50,000 pounds, estimates the crane expert. The structure would be dismantled piece by piece, rather than jacked down to a lower level, as is typically done.
Another option would be to use gin poles, or lattice booms tied to guy wires mounted to the roof, to help disassemble the rig and gently lower it to the ground. Either option would be a delicate engineering project of its own.
"They'll have to put their heads to it," says McGettigan. "It's not going to be simple."
According to the city, contractors are more likely to use a third option: erecting another crane next to the damaged one. The replacement crane would be used to dismantle the Favco and then stay on to finish the building.
"That can take weeks, but once the boom is secured we should be able to minimize any disruption on the street below," says Bloomberg, who adds that contractors will soon be "tying the boom to the building so that you can then work on top of it" in an effort to starting "shrinking the zone around the frozen area" in the crane's footprint.
Looking for quick answers on construction and engineering topics?
Try Ask ENR, our new smart AI search tool.
Ask ENR →
What About Costs?
Once the broken jib is out of the picture, removing the old crane and replacing it with a new one could cost up to $3 million and take up to one month, crane experts tell ENR.
"The labor alone to bring it down and the equipment...will run $250,000 to $500,000," says the crane engineer. "And that's assuming not a lot of problems." The cost to erect a tall tower crane in New York City runs around $1 million, the source adds.
The owner and developer, Extell, or the builder's risk insurance policy would likely pay for the turnaround, the expert source notes.
"Certainly, it's a wind event," the expert says. Lend Lease did not respond to ENR's questions about insurance.
This story was updated on Oct. 31 at 8:46 P.M.
