Flushing Town Center is a mixed use building in Queens consisting of a retail mall steel podium and six concrete residential towers on top of the podium. After the recession of 2008, only three of the six residential towers were completed. The west towers and steel transfer floor below, at the mall roof level was left incomplete. The existing conditions included permanent roof trusses and columns that had been terminated at the mall roof level.
Stonebridge scope of work began with a scan survey existing steel conditions for use by Cives Steel Company to detail the new transfer floor steel. The second phase of work included the removal of existing and installation of new connection material on existing steel, plus the installation of column stubs throughout the footprint to accept the new infill steel. The third phase of work was the erection of 2500 tons of new transfer floor girders and infill framing, plus metal deck, to support the future concrete towers above.
The project site was bounded by the existing mall to the east and south, elevated train tracks to the north, and an active loading dock to the west and south.
This presented unique challenges to the project as it required picks of up to 30 tons to be made from a delivery point up to 250' feet away from final location.
In lieu of a larger crawler crane, Stonebridge elected to utilize the permanent in place roof trusses under the three future towers to support three separate crane runways on top of the operating mall below. Stonebridge utilized two Manitowoc 999 cranes to complete the project, one roof based crane which was hoisted and built in place on three separate runways, and one ground based crane acting as the unloading and staging crane, and the assist crane to assemble, disassemble, and relocate the roof crane.