A new 63-story office/retail building in New York City is one of five towers being constructed on the World Trade Center site, commemorating the events of September 11, 2001, and symbolizing the rebirth of Lower Manhattan.
The 975-foot-tall Tower 4 (the fourth largest tower on the new site) features two distinctly shaped floor plates: For the lower- and mid-rise sections, the floor plates are in the shape of a parallelogram echoing the configuration of the site; the highrise section will feature a trapezoidal floor plate. The trapezoid, shaped and fluted to open toward the tip of Manhattan, will be triangulated from the lower floors to face the largest structure in the complex, the Freedom Tower.
The structure has four structural concrete levels below-grade with slabs up to 36 inches thick and columns up to 7 feet in diameter and 6 feet by 6 feet square. The concrete contractor, Roger and Sons Concrete, Inc., used Doka's framed formwork Frami with integrated working platforms to construct the tower's core and shear walls, which allowed them to handset the outside formwork under the slabs rather than climbing it.
With the concrete work planned for completion by 2011, Tower 4 along with Towers 2 and 3, are slated to be finished in 2012, marking a major milestone in the redevelopment of downtown New York.