Grove's GMK7450 all-terrain crane.
A Grove GMK7450 all-terrain crane with a MegaWingLift attachment helped with restoration work on the Washington National Cathedral in Washington, D.C. after it sustained extensive damage in the magnitude-5.8 earthquake that shook the East Coast in August.
W. O. Grubb Crane Rental, the lifting company contracted to help with the repair process, used the GMK7450 primarily for its high reach. Operator Jim Tracey said that despite the relatively light lifts, the company needed a high-capacity crane to avoid damaging the cathedral stairs and landscaping. The crane was positioned 230 feet from the structure and had to reach up to 320 feet to perform the required lifts.
“The biggest challenge on this job was how far away we positioned the crane and also the height of the picks,” said Tracey. “There was no way to get in close to the building, so we needed a high-capacity crane that could reach across the grounds of the cathedral. The GMK7450 was a great choice.”
The crane was configured with 163 feet of main boom and 260 feet of luffing jib. It was fitted with full counterweight of 176 tons and configured with the MegaWingLift attachment, which enhanced the crane’s capacity by 60 percent, giving greater strength to the boom by avoiding side deflection.
The boom assembly, supported by a Nelson boom launch trailer, took 20 minutes to erect and the entire crane was set up in four hours. Transporting the GMK7450 was achieved by removing the boom and the rear outrigger box.
For the restoration, the GMK7450 first helped assemble support beams around the upper portion of the cathedral for scaffolding, which provided access for stonemasons to repair the hand-carved limestone exterior. Next, the crane removed four pinnacles from the top of the cathedral so they could undergo renovation on the ground. The pinnacles each weigh approximately 5,000 pounds and were picked from a height of 320 feet.
Contractors worked to make the cathedral safe for the public in time for the consecration of the new bishop of Washington on November 12. The cathedral typically receives more than 30,000 visitors per month.
Source:
