Freedom Tower: D.Ann Shiffler reports

When complete New York's Freedom Tower will stand next to the site of the World Trade Centre twin towers that were destroyed in the terrorist attacks of September 11, 2001. Construction began on April 27, 2006, and by December, work on the ‘bath tub’ foundations was nearing completion, allowing the first above-ground columns to be erected.

The underground diaphragm walls are being excavated down to the bedrock, and will serve as dams to prevent water from seeping in from the Hudson River. They will also maintain steady groundwater levels within their perimeter - hence the ‘bath tub’ nickname. The work is being carried out by two Liebherr HS 855 duty cycle cranes rigged with slurry grabs.

By December this work had progressed far enough to allow the erection of the first 30 foot (9.14 m), 25 tonne steel columns, which were bolted into place to form the southern perimeter of the new tower.

With 2.6 million square feet (240000 m²) of office space, the 1,776 foot (541 m) tall Freedom Tower will also feature amenity spaces for tenants, an observation deck, restaurants, and broadcast and antennae facilities. In addition to the rapid transit system, the basement area will offer access to shops and restaurants.