W O Grubb Crane Rental used a GMK7450 all terrain crane selected to make high reach lifts of scaffolding for masons and to remove damaged stones.

Operator Jim Tracey said a high-capacity crane was required despite the lightness of the scaffolding to prevent damage to the cathedral stairs and lanscaping.

The crane was set up 230ft from the cathedral’s base, configured with a MegaWingLift attachment, to reach the height of 320ft required.

The crane traveled by road to the site after removing the boom and the rear outrigger box to achieve a gross vehicle weight of below 60USt.

Once onsite, configuring the GMK7450 for both height and capacity required use of the MegaWingLift attachment along with 163ft of main boom with 260ft of luffing jib, and 176USt of counterweight.

The firm used the MegaWingLift to add 60 percent capacity, while preventing side deflection on the boom.

Rapidly positioning the crane, W O Grubb Crane Rental took only 20 minutes to erect the boom assembly, held up by the Nelson boom launch trailer. The entire set up of the crane took only four hours, said Manitowoc.

The GMK7450 first lifted scaffolding support beams onto the upper part of the exterior, as masons would need to climb up onto scaffolding to reach the areas of stonework requiring repair.

The crane then removed four pinnacles from the top of the cathedral and placed them carefully on the ground for the masons to begin renovation work. The pinnacles weighing about 2.3t (2.5USt) were picked from a height of 320ft.

Tracey, who has been operating GMK7450 cranes since 2003, said, “The biggest challenge on this job was how far away we positioned the crane and also the height of the picks. 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 smooth operation of this crane is a major asset on jobs like this,” he continued. “We’ve had this crane for three years and have come to rely on it extensively for sensitive lifts.”

The cathedral reopened on the 10 of November, in time for the consecration ceremony for the new bishop of Washington.