Freedom Tower to be safest building in US

Real Estate Weekly, July 6, 2005 by Barbara Nelson

The redesigned Freedom Tower takes into consideration the NYPD's and the NIST recommendations, making it the safest and most structurally sound building in the United States, once it's finished in 2010.

"There's no question it's going to built to the highest standards of any high-rise ever in the United States of American," said Governor George Pataki, at a press conference this week debuting the iconic tower's redesign. Last week, the National Institute of Technology and Standards, the federal organization that studied the World Trade Center collapse, released a draft report detailing 30 recommendations on the design and construction of high-rise buildings.

Those recommendations, as well as those by the New York Police Department earlier this year, were a high-priority in the design of the Freedom Tower.

The Freedom Tower's height remains at 1,776 feet, but the structural design has been reinforced for protection against truck bombs and other potentially catastrophic events. At the request of the NYPD the tower has also been placed further back from West Street to 90 feet, from 25 feet.

"The police department of New York provided us with a set of standards," said owner and developer, Larry Silverstein, of Silverstein Properties. "We analyzed them and concluded that this building would be built to those standards. Essentially they embrace the requirements specified by the government of the United State, with respect to foreign embassies."

As recommended by the NIST, reinforced concrete has been added throughout the structure, Silverstein said.

"What we have is a building which, in this case, will have a core that will be constructed of reinforced concrete, 12,000-pound concrete, which is the densest form of concrete that you can pour," he said.

In line with the recommendations NIST, occupant's safety is the highest priority.

"The concrete core will be reinforced with steel bars on every floor, in excess of 100 tons of reinforcing bars," Silverstein said. "That concrete core and the shear wall will surround the elevators, the stairs, the sprinkler system, the communication system--all the life-saving provisions."

Ysrael A. Seinuk, P.C. a world-renowned structural engineer, said the most significant change in building design recommended by the NIST was "the desire for enhanced fire resistance, evacuation issues and performance of the structures."

"The public must be made clearly aware that these regulations do not eliminate damage that may be caused by terrorism, but they address, among other normal situations, a heightened desire to protect life," said Seinuk.

The base of the tower has also changed. Instead a twisted parallelogram, the new plan calls for a cubic base with eight isosceles triangles forming an octagon, and culminating in an observation deck at 1,362 feet and a glass parapet at 1,368 feet.

In honor of the Twin Towers, the plot of the new tower will measure 200 feet by 200 feet--the same size as the footprints of the original buildings. The redesign is more a slender frame, but retains plans for 2.6 million square feet of office space. A spire supported by a cable structure will sit atop the tower and will emit light-meant to evoke the Statue of Liberty's torch.

While incorporating enhanced security requirements, the building will feature entrances on all four sides, making it open and accessible and connected to the community and street life that will surround it. These entrances will also provide views of and access to the adjoining memorial.

Additionally, the new tower will serve as a model of energy efficiency and environmental sustainability, incorporating state-of-the-art energy-saving technology, environmentally friendly building materials, water conservation features, and ventilation systems to improve indoor air quality.

David Childs' Skidmore, Owings & Merrill LLP, is the architect for the project; Tishman Construction Corporation is the construction manager; Cantor Seinuk Group is the structural engineer, along with Schlaich Bergermann & Partners GbR. Jaros Baum & Bolles, Inc. is the MEP engineer and sustainability consultant along with Green Order. Claude R. Engle is the lighting designer; Philip Habib & Associates is the civil and transportation engineer; Peter Walker Partners is the landscape architect; Ducibella, Venter & Santore and Weidlinger Associates are responsible for security; Cerami & Associates are handling acoustics; Jaros Baum & Bolles are responsible for vertical transportation; geotechnical engineers are Mueser Rutledge Consulting Engineers; wind tunnel testing will be done by Rowan Williams Davies & Irwin Inc.; Cini-Little, International, Inc. is the restaurant consultant; Ralph Applebaum and Associates will be invovled with exhibition and observation decks; digital visualization will be handled by dbox Studio, Screampoint and @radical.media and; Radii is responsible for models.