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Barnhart’s Mount Vernon and Kent, Washington branches joined forces to perform a joint venture tower crane dismantle in Seattle. 

The team set up a GMK7550, an all-terrain mobile crane, with 264,000 pounds of counterweight and Mega wing attachment and 200 luffer. They utilized an LTM1090 to install the luffer from one position in the crowded corridor. To help with the ground bearing pressure restrictions (due to an underground vault for utilities), the team utilized 8’ x 16’ engineered steel mats, wood ramp mats, and 8’ x 10’ engineered steel mats for proper ground bearing pressure displacement.

There were several other challenges to work around. Metro-trolley wires to the west had to be avoided, and the proximity of a four-story brick building allowed just 1’ of clearance for the mega wing attachment. A tree to the north had to be trimmed for the counterweight to clear. The jib assembly had just 1’ of clearance to the east and the crew had to short rig it for the tower tip to clear. 

Plus, there were lots of pedestrians.   

Once the crane was in place, the crew dismantled the tower crane and Barnhart lowered the pieces to awaiting trucks in the narrow street. It took over 15 loads to remove all the pieces. Despite the challenges, the project was completed in just two days.