Freedom Tower Design Undergoes Fourth Revision

Designers return to aesthetic concerns at the World Trade Center tower after addressing safety issues. Also, an affordable design competition collects ideas for a new South Bronx development.

Redesign for Freedom Tower Base

The Freedom Tower project in Manhattan has undergone yet another revision to its design even as foundation work began this spring.

Only a year after a major redesign that responded to concerns by public safety officials over the Freedom Tower's positioning and façade materials, David Childs of New York's Skidmore, Owings, and Merrill, the chief architect on the project, issued a new plan in June to replace a 200-ft.-high, 3-ft.-thick concrete base sheathed in titanium. The base had been designed to help the building resist a truck bomb, but had an imposing appearance.

The revision replaces the titanium enclosure with panels of safety glass, which if broken shatters into tiny spheres instead of shards. The glass will also function as a collection of prisms, refracting light onto the sidewalk.

The other major change is to the spire that will reach to 1,776 ft. It will no longer fan out at its base but instead be seated on a raised pedestal, creating the illusion of floating.

The new design marks the fourth evolution of the tower. The first design, a conceptual plan for the entire World Trade Center redevelopment by Daniel Libeskind of New York, was selected as the site plan in February 2003 and originally called for an angular tower with a spire stretching to 1,776 ft.

A new design unveiled in December 2003 came through a collaboration of Childs and Libeskind's work. This version sited the spire at the northwest corner of the tower atop a lattice frame above the 72nd floor.

The lattice space would have housed a farm of wind turbines to comply with a Lower Manhattan Development Corp. requirement for the building to exceed New York's state energy code standards by 20 percent.

But in April 2005, only weeks before initial foundation work was to begin, city security officials convinced project leaders to heed their concerns that the building's base was too close to the street and vulnerable to truck bombs. Childs responded with the design of a concrete base and titanium panels, a symmetrical façade to increase the tower's structural integrity, and a footprint shifted diagonally away from the corner of West and Vesey streets.

Additionally, the new design filled in the latticework to create a uniform surface and replaced the wind turbines with an internal rainwater recycling system.

Construction work on the tower remains below grade this summer with tasks focused on foundations, excavation, and integration with other features on the site. The tower is set for completion in 2012.

Competition for Affordable Housing Design

A juried competition to design an affordable housing complex is under way in New York's South Bronx neighborhood. Dubbed New Housing New York, the competition is sponsored by the New York City Department of Housing Preservation and Development in conjunction with the New York chapter of the American Institute of Architects.

The winning architect-developer team will design the Legacy Project, a 150-unit, mixed-use, mixed-income building on a 40,000-sq.-ft. vacant city-owned lot at East 156th Street and Brook Avenue. The developer of the $4 million site, which will be sold to the winning team for $1, will be able to apply 20,000 sq. ft. of air rights from an adjacent privately-owned lot.

The site presents several design challenges because it is steeply sloped and borders a retaining wall and abandoned rail line in the Bronxchester Urban Renewal Area.

The New York State Energy Research and Development Authority is also part of the team overseeing the competition, which will give preference to projects minimizing energy consumption, using environmentally sound materials, and incorporating "healthy living" amenities such as exercise rooms and outdoor space.

The jury of architects, city officials, community representatives, and developers will select the winning team in January. The team will be able to apply a $145,000 New York State Department of Environmental Conservation environmental remediation grant toward the site's redevelopment. Construction is slated to begin in 2008.

Safe Tower Design Initiative to Use WTC Lessons

A study into safer evacuation route design in skyscrapers now under way will include insight gleaned from interviews with up to 1,000 evacuees from the Twin Towers before they fell as a result of the Sept. 11, 2001 terrorist attacks in New York. The final report is due next year.

The High-Rise Evacuation Evaluation Database, dubbed Project HEED, started in 2004 and will focus on fire safety engineering and human behavior in evacuations. The project involves a collaboration of three United Kingdom universities and is being funded by the UK Engineering and Physical Sciences Research Council.

The project has been endorsed by the New York City Department of Buildings and the Fire Department of New York, and is getting research support from John Jay College of Criminal Justice in New York, Pace University in White Plains, N.Y., and Polytechnic University in Brooklyn.

The project's current phase involves a series of interviews with World Trade Center evacuees from New York, New Jersey, and Connecticut.

In order to recruit participants, the organizers will donate $20 for each evacuee interviewed to one of three Sept. 11-related charities. The interview subjects will vote to decide whether the Leary Fire Fighters Foundation, WTC Survivors' Network, or September Space gets the proceeds.

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