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When Washington, D.C.-based contractor Lenkin Enterprises was contracted to work on two area construction projects, the choice in cranes was obvious. For both the renovation of Glenstone, a private modern art museum in Potomac, Maryland, and the repurposing of an office building at Georgetown University in Washington, the company selected two Potain MDT 809 tower cranes, the largest Potain topless crane available in the U.S.
For the museum project, a crane with a long jib and extended reach was required to minimize disturbance to the museum’s landscape, which is in a meadow with native plants and wild grass. To reduce environmental impact, the project called for the use of a single tower crane instead of two. That meant using one crane to reach most of the building’s perimeter to make the work feasible.
“The Potain team and the Manitowoc Lift Solutions division worked with us to find the right solution for the museum project so we could adapt the MDT 809 to meet our needs,” said Michael Lenkin, structural engineer at Lenkin Enterprises. “We were able to get a jib for the crane with the capacity our client wanted on a static base, despite having to shoehorn the crane into an alcove at the museum.”
The MDT 809 at the museum project is notable for being the first in North America to use the ZY854 cross-shaped base, which supports high working heights without adversely impacting set-up or operation costs. The cross base is supported on pile caps and micropiles to transfer the loads below the museum. The crane and foundations were coordinated carefully with existing buried utilities.
On the museum jobsite, the MDT 809 crane is also the first to use a 279-foot jib and the first to support both the 2-part/4-part trolley (SM/DM) and full-time 2-part trolley.
At Georgetown University, the Potain MDT 809 proved a central figure in repurposing a 40-plus-year-old office building. The crane’s capacity was crucial in removing and resetting granite-clad precast panels, with estimated weights of approximately 24,000 pounds.
The MDT 809 on the office building project also set structural steel and performed demolition tasks. The project involved significant structural work, and the MDT 809 at the site had the hook reach with an SM/DM trolley, and the 12.8-ton tip capacity required.
On the office building site, the MDT 809 was supported on a ZY854 ballasted cross base on top of the existing structure using existing and temporary structural steel columns down to the building’s foundation.
For over 30 years, Lenkin Enterprises has worked with and invested in tower cranes. While the company has long-running experience working with Potain cranes dating back to 1994, the two MDT 809 units are the first they have owned.
“These cranes were essential for meeting specific lifting requirements on two challenging projects,” Lenkin said. “Manitowoc Lift Solutions and the Potain team made it possible by consistently delivering on our project-specific needs.”
