Official Freedom Tower Thread

[NYguy]

NY TIMES

Security at Symbol of Resolve: Many Demands on New Ground Zero Tower

By GLENN COLLINS and DAVID W. DUNLAP

June 7, 2005

Once intended as a shimmering, soaring declaration of political resolve and architectural ambition, the Freedom Tower at the site of the World Trade Center is being reimagined as something more impregnable. So the challenge now faced by its designers is to keep it from looking like a high-rise bunker.

The current design of the Freedom Tower includes exposed columns at the base one of the security concerns that led Gov. George E. Pataki to order the redesign of the tower, now under way.

The Freedom Tower may end up with a structurally massive base that is distinctly different from the upper office floors. The designers may use stainless-steel cladding, reinforced glass or even translucent concrete, a new material embedded with strands of glass that transmits light and shadow through seemingly impervious walls.

The redesign, ordered by Gov. George E. Pataki last month in response to security concerns raised by the New York Police Department, will add tens of millions of dollars to the building's estimated $1.5 billion cost. Less than four weeks before the governor's deadline of the end of June, details of the redesign are still being worked out, said Silverstein Properties, developers of the Freedom Tower and 7 World Trade Center, and Skidmore, Owings & Merrill, the architects of both buildings.

The urgent push to fortify what had already been called "probably the safest building in the world" by its chief architect, David M. Childs of Skidmore, has raised broader questions about the site planning and architectural criteria for the trade center redevelopment project.

Today, two City Council committees will consider security concerns at the Freedom Tower and the larger issue of Police Department involvement in the design and construction of big buildings and development projects.

If antiterrorist security had been the one and only consideration at the trade center site, the first designs for the Freedom Tower and other projects would seem to flout some basic axioms put forth by the Defense Department, the Federal Emergency Management Agency and the American Institute of Architects.

In publicly available reports, they advise that attention-getting architectural symbols are prime targets and should be located far from potential vehicle-borne bombs; glass facades can be lethal in a blast; train stations and underground garages are especially vulnerable to attack; and spacious, column-free interiors under other structures may be liable to collapse.

At the trade center site, planners have envisioned a defiantly tall skyscraper laden with symbolism on a site bounded by a heavily trafficked state highway; a memorial that is expected to draw millions of visitors; and a transparent, glimmering museum directly above the broad, column-free mezzanine of a busy commuter rail and subway station. City streets will lace the site. Below them will be a network of ramps, roadways, loading docks and parking spaces.

Officials still intend to follow this broad development outline, but the design of the Freedom Tower is being revised to provide a greater shield from vehicle-borne explosives. This is generally described as "the most important consideration" in antiterror structural design by the emergency management agency, even though the last attack on the trade center was an aerial assault. Cars and trucks have proven to be an effective way of delivering large explosive charges.

The first version of the Freedom Tower was unveiled in 2003 and publicly embraced by city and state leaders, including officials of the Port Authority of New York and New Jersey, which owns the site. The design placed the building as close as 25 feet from West Street-Route 9A. From a parallelogram base ringed by an arcade of exposed columns, the tower was to twist as it rose, culminating after 70 floors of occupied space in an open-air superstructure of cables, power-generating windmills and an off-center spire meant to echo the Statue of Liberty.

People who have been informed about the redesign discussions say that the architects will probably set the building back at least twice as far from the street to limit blast damage from a car or truck bomb, and untwist it. The new building is likely to have a square floor plan, with a different summit and several more occupied floors than were in the original design.

Windows below the 150-foot level will almost certainly be fewer and smaller, and views will be limited. The arcade around the base may be eliminated.

Managers of the redevelopment insist that the trade center site can be made safe through a series of protective zones, with checkpoints, bollards and other barriers.

And they say the Freedom Tower and other sensitive buildings can be hardened with blast-resistant materials. Some, like Daniel Libeskind, the site's master planner, say the new World Trade Center "will be as safe as any site in the world today, if not safer."

"We are responding to the need for security, but we are also responding to life," Mr. Libeskind added. "We cannot make the Freedom Tower a tower of fear."

There is no denying, however, that this site has been attacked twice. In this context, the assessment of security is something of a gamble against unknowable, and possibly deadly, odds.

Much about security preparedness has been deliberately shrouded in secrecy. Some experts and public officials spoke anonymously for this article because they are forbidden contractually, or by the agencies they work for, to publicly discuss questions of safety. They also say that specifying security details is an invitation to terrorists to exceed them.

Some with knowledge of the Police Department's evaluation of risk on the site said that its experts favor caution in security tradeoffs, but do not want to be unrealistic in demanding assurances of absolute safety. These experts acknowledge that an urban site cannot be built that is totally immune from attack, but insist that its buildings must not be so vulnerable that they invite an attack.

The Freedom Tower's original "threat and risk assessment" report, these experts say, specified that the building achieve the security standards for a high-level government structure in Washington, capable of resisting a 5,000-pound truck bomb - more than the size of the 4,000-pound Oklahoma City explosion in 1995.

Though such criteria were unusually high for an office building, the police rejected them as inadequate, given the Freedom Tower's height, its role as a political statement, its planned glass exterior and its proximity to West Street-Route 9A.

The police did suggest some redesign options and submitted a report detailing the history of truck-bomb attacks, according to some with knowledge of the ensuing dialogue. Finally, in early May, the governor announced that the Freedom Tower would be moved away from West Street, and that the tower exterior would be strengthened.

Untwisting the torqued design of the original tower would reduce the size of the building's base, and help meet the Police Department's requirement that it be set back farther from the street.

The original distance of 25 feet from West Street-Route 9A will be doubled, at a minimum; as much as 65 feet is conceivable. Since the distance from Vesey and Fulton Streets will be considerably less, traffic on those streets will most likely have to be limited.

Such seemingly minor differences matter "because explosive pressures decay so rapidly with distance. Literally, every foot counts," said Eve Hinman, the president of Hinman Consulting Engineers and a principal author of "Primer for Design of Commercial Buildings to Mitigate Terror Attack," issued in 2003 by the emergency management agency.

The Freedom Tower architects have said that the building's stairwells, like those of the new 7 World Trade Center but unlike those of the twin towers, will be protected by reinforced concrete instead of wallboard, and will be pressurized to keep stair passages from filling with smoke.

Architects are planning to include separate emergency-responder staircases and elevators that could be used in a crisis. The designers hope to incorporate redundant sets of pipes feeding the fire sprinklers. And signal-boosting radio repeaters are planned to enhance radio communication.

The security consultant on the Freedom Tower project is Weidlinger Associates, an engineering firm with decades of experience in blast resistance.

Over all, Mayor Michael R. Bloomberg has said, the redesigned Freedom Tower will be built to achieve United States embassy security standards. The base, up to 150 feet, will have what consultants call "a hard bottom," built to Department of Defense standards of blast resistance. Although the size of this threat is classified, an emergency management agency report recommends protection against at least 10,000 pounds of explosives. (The largest truck bombing against an American target, the Marine barracks in Beirut in 1983, involved some 12,000 pounds of explosives.)

Among the sheathing materials under consideration for the Freedom Tower are stainless steel, laminated glass and translucent concrete, an expensive material, some of which is sold under the brand name LiTraCon, for light transmitting concrete.

The redesign is likely to eliminate arcade columns, which the emergency management agency recommends avoiding in its design primer since they are "primary structural elements that hold up part of the building," said Dr. Hinman, the author of the report, in an interview.

To compensate for the reduction in floor space caused by the redesign, the occupied portion of the building, originally to be 70 stories, will probably increase by another few floors.

Publicly trumpeted flourishes at the top of the building - a wind farm, an observation deck, restaurants and exterior cabling at the spire - are likely to change. But none of the original elements has thus far been written off. One possibility is that a single antenna structure will allow the tower to reach 1,776 feet.

That height remains the governor's goal, even though some security experts say it substantially raises the security ante. "In my opinion the height is a negative because of the risk of another aerial attack," Dr. Hinman said.

Mr. Libeskind, however, said that "a four-story building on that site wouldn't be less attractive to those who want to destroy this country."

Carl Galioto, a partner at Skidmore, said, "Our client and the governor have asked us to design something great."

Greatness aside, the security goal is to make the Freedom Tower structurally reusable after an explosion. Such engineering standards do not assume that the lives of all the people within the building could be saved in an attack, though hardening the structure could prevent many deaths.

The original plaza of the World Trade Center, which acted as a sometimes wind-swept barrier to the surrounding neighborhood, might have been preferable purely from a security point of view because it eliminated streets running through the site.

But Alexander Garvin, an urban-planning professor at Yale University, championed the re-creation of the old street grid when he headed planning at the Lower Manhattan Development Corporation in 2002 and 2003.

"Either we live normal lives with normal streets and normal sidewalks, or we go back to living in fortresses as they did in the Middle Ages," he said in an interview.

Many prominent buildings are quite close to streets. These include Grand Central Terminal and the Empire State Building and structures under construction like the Bank of America Tower at 1 Bryant Park and the future glass-clad headquarters of The New York Times across Eighth Avenue from the Port Authority Bus Terminal. This transportation hub has for months been undergoing a security upgrade. Bare steel support columns in upstairs parking areas have been encased in reinforced concrete to enhance their fire and blast resistance.

Several experts question the location of the Freedom Tower near a state highway, three through streets and the headquarters of at least two high-profile companies, American Express and Verizon.

"The best thing from a security standpoint would be to move the Freedom Tower to Church Street," said Guy J. Nordenson, a structural engineer and a professor of architecture at Princeton University who is currently involved in several projects at the trade center site. "You could control truck traffic access better on Church Street than on West Street, and you would be able to achieve setbacks more easily on that site."

Trucks are not the only threat. "Large passenger vehicles like S.U.V.'s are able to carry more explosives unobtrusively and are a major hazard," Dr. Hinman said. She said the current estimate of how much a big S.U.V. can carry is the equivalent of the charge used in the Oklahoma City bombing.

To make underground parking safe, all vehicles entering the subterranean roadways would be subject to inspection at the entrances off Liberty and Vesey Streets, said Stefan Pryor, president of the Lower Manhattan Development Corporation.

Security experts underscore that terrorists' intentions cannot be predicted, and they recommend the installation of specially designed air intakes and ventilation systems in buildings at the site to counter radiological, chemical and biological threats.

Also undergoing scrutiny is the $2 billion PATH station and transportation hub by the architect Santiago Calatrava, which poses many engineering challenges, including the routing of the PATH tracks directly under the Freedom Tower site, meaning that the tower's supporting columns must be threaded among the rails.

Mr. Calatrava said in an interview that he could deliver "a beautiful building that accomplishes all the needs of security," adding that "95 percent of people in the station will be in lower levels," and therefore more shielded from the possibility of explosion. The distance from Church Street to the above-ground part of the terminal has not yet been determined by the Port Authority, which runs PATH, but engineers have set 50 feet as a goal.

To support the bulk of the museum building, transfer girders will be used to redistribute its weight out to the sides of the PATH station mezzanine directly below. Generally speaking, the use of transfer girders is "strongly discouraged" in the emergency management agency's primer.

"If you lose the transfer girder, a lot more of the building is going to come down," Dr. Hinman said in an interview. The failure of structural transfer systems contributed to the collapse of the original 7 World Trade Center and of the Alfred P. Murrah Federal Building in Oklahoma City.

But the transfer girders above the PATH station have been designed "in a way that the global collapse of the building would be almost impossible," Mr. Calatrava said.

The museum is to have a "crystalline facade" of glass prisms set into walls of wood or terra-cotta designed to capture light, said Craig Dykers of the Norwegian architectural firm Snohetta. "We have been apprised of the security requirements," he added, "and we plan to meet and exceed them."

But relatives of those who died in the trade center have expressed concern about all of the glass facades planned for the site, said Monica Iken, whose husband, Michael, died in the south tower. "For many family members who were talking on the phone to their loved ones," she said, "the last thing they heard was the shattering of glass."

Based on past terrorist incidents, Dr. Hinman said, up to 80 percent of injuries from terrorist attack are from breaking glass.

In an explosion, even safety glass "breaks into thousands of pellets, each with sharp edges flying at near-supersonic speed," according to "Security Planning and Design," a 2004 safety primer from the American Institute of Architects. The Department of Defense requires a minimum of quarter-inch-thick laminated glass for exterior windows and glazed doors.

The police have neither seen nor approved the redesign of the Freedom Tower, but on the basis of briefings about the safety criteria for the revision, they have judged that the new building will be very resistant to a truck bomb, though they will reserve comment until they see more specifics.

The police have not yet given security approval to the PATH station or to the museum that will be above it, but some who have knowledge of Mr. Calatrava's presentation to law enforcement agencies say he impressed them with the security awareness he demonstrated from his designs of seven previous stations.

In the end, some decisions about security at ground zero may necessarily be arbitrary, political and imperfect: in short, a compromise. Family members of trade center victims underscore the fearful gravity of these choices.

"From the beginning it has been a rush to rebuild," said Monica Gabrielle, co-chairwoman of the Skyscraper Safety Campaign, who lost her husband, Richard, in the south tower. "But let what they build on that site be a monument to a change in mentality about safety and security. No one should ever suffer like my husband did, and the 3,000 other families. We want no one to walk in our shoes, ever."

[NYguy]

Some interesting points from that article:

The Freedom Tower may end up with a structurally massive base that is distinctly different from the upper office floors. The designers may use stainless-steel cladding, reinforced glass or even translucent concrete, a new material embedded with strands of glass that transmits light and shadow through seemingly impervious walls.

People who have been informed about the redesign discussions say that the architects will probably set the building back at least twice as far from the street to limit blast damage from a car or truck bomb, and untwist it. The new building is likely to have a square floor plan, with a different summit and several more occupied floors than were in the original design.

Windows below the 150-foot level will almost certainly be fewer and smaller, and views will be limited. The arcade around the base may be eliminated.

To compensate for the reduction in floor space caused by the redesign, the occupied portion of the building, originally to be 70 stories, will probably increase by another few floors.

Publicly trumpeted flourishes at the top of the building - a wind farm, an observation deck, restaurants and exterior cabling at the spire - are likely to change. But none of the original elements has thus far been written off. One possibility is that a single antenna structure will allow the tower to reach 1,776 feet.

[jazzman]

I think the 1776 foot Freedom Tower is beautiful. The open space on top is a memorial and should be open. The plans called for the position of the building to be in precise alignment so that every September 11th at 8:45 the sun will be reflected up the entire length of the structure illuminating the interior of the open framework at the top. This would be spectacular.

Trumps idea for two ugly boxes is truly "thinking inside the box" something he's good at. It would be a little creepy to see the same thing replaced. It's kind of like taxidermy. I love seeing the Lincoln Memorial but wouldn't if Lincoln (himself) was stuffed and sitting inside.

My 'two cents'.

B)

[NYguy]

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[NYguy]

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[monsoon]

You know, I still don't like it. Other than it's size it is a fairly unremarkable building and I doubt it will have the same unique factor the original buildings had. Take it out of the NYC skyline and I doubt that people will recognize it.

[SmellyCat]

My first impression is that it's a HUGE improvement over the 2002 Libeskind design. I think it's fairly unique looking. They could have done something better with the top of the building though...I dont like the way it's been squared off.

But it may yet grow on me.

[nyxmike]

I really like it actually - it's a very modern version of the North Tower. I think it's very fitting - everyone wants some crazy modern design that doesn't fit the skyline at all (like Fosters - it's nice but it doesn't fit at all). I think this is perfect.. but thats my opinion.

[IBruton]

I really like it actually - it's a very modern version of the North Tower. I think it's very fitting - everyone wants some crazy modern design that doesn't fit the skyline at all (like Fosters - it's nice but it doesn't fit at all). I think this is perfect.. but thats my opinion.

<{POST_SNAPBACK}>

I think we should rebuild the original towers just as they were. But, this rendering is the best that I've seen. It reminds me of the John Hancock tower in Chicago.

[orulz]

I like the design. Simple, elegant, slick, nice. One for the years.

What I don't like, however, is the 200 foot high bomb shield/shimmering wall at the base. Wasn't the biggest criticism about the old WTC that it was dead at street level? Do what you gotta to do in order to shield the structural elements, but then build something inviting around them.

I don't care for the name, either. Freedom is a great concept, but the name "Freedom Tower" smacks of a panicky post-9/11 time when Jeep renamed the Cherokee to the "Liberty" and everything was called "freedom this" and "freedom that" to "remind ourselves" of that the US is supposed to be free. Meanwhile, Congress was quickly eroded our freedom and rights with shady and hasty legislation such as the PATRIOT act. The word "freedom," in this context, makes me think of exactly the opposite: tearing our very principles apart to become united in totalitarianism in order to protect the motherland from the nebulous threat of terrorism.

I say, call it "The World Trade Center." That'd be the most appropriate tribute to the fallen twin towers.

[eastsider]

I really like it actually - it's a very modern version of the North Tower. I think it's very fitting - everyone wants some crazy modern design that doesn't fit the skyline at all (like Fosters - it's nice but it doesn't fit at all). I think this is perfect.. but thats my opinion.

<{POST_SNAPBACK}>

I completely agree with you. The squared-off top pays homage to the original towers, yet the overall design can stand on its own. Glad to see this rather than the original Freedom Tower design.

[nyxmike]

I like the design. Simple, elegant, slick, nice. One for the years.

What I don't like, however, is the 200 foot high bomb shield/shimmering wall at the base. Wasn't the biggest criticism about the old WTC that it was dead at street level? Do what you gotta to do in order to shield the structural elements, but then build something inviting around them.

I don't care for the name, either. Freedom is a great concept, but the name "Freedom Tower" smacks of a panicky post-9/11 time when Jeep renamed the Cherokee to the "Liberty" and everything was called "freedom this" and "freedom that" to "remind ourselves" of that the US is supposed to be free. Meanwhile, Congress was quickly eroded our freedom and rights with shady and hasty legislation such as the PATRIOT act. The word "freedom," in this context, makes me think of exactly the opposite: tearing our very principles apart to become united in totalitarianism in order to protect the motherland from the nebulous threat of terrorism.

I say, call it "The World Trade Center." That'd be the most appropriate tribute to the fallen twin towers.

<{POST_SNAPBACK}>

I agree about the name, but I bet everyone (atleast in NY) will still call it The World Trade Center.

[M. Brown]

I didn't mind the old design but this is just so much better. No lattice.

[Zissou]

I really like this design. I didnt really mind the previous design, i actually liked it from the stand point that it was something innovative but I think people will appreciate this much more. From the looks of it it will contain more space as well. Will it still be the symbolic 1776 ft?

[jazzman]

Not as dull as Trumps idea (thank God), not a odd as the original plan (which many hated). This design is kinetic, it moves with your eye and changes depending on your viewing point. Using the symbolic 1776' height takes it out of the WTB race, which I feel they should rethink. This should be the WTB (absolutely).

B)

[ironchapman]

It's the best plan I've seen so far.

I wish the spire had a little more around the bottom, though, like a crown or a pyramid or something. It looks fine as it is with or without the things I suggested, though.

[RiversideGator]

I like it MUCH better than the previous design and it really is more attractive than the originals. It would be nice to be the tallest though, although 1776 may not be the record when/if this is completed anyway.

[AvianKeahi]

...Using the symbolic 1776' height takes it out of the WTB race, which I feel they should rethink. This should be the WTB (absolutely).

B)

<{POST_SNAPBACK}>

Yes. Is it me, or have American developers lost their ambition to build dramatic, height-challenging towers? Yes, I know it's a matter of economics, but to a lot of Asian builders/developers/owners, cost is not the issue. It's the pride (though some would say the folly) of building high.

[jazzman]

Yes.  Is it me, or have American developers lost their ambition to build dramatic, height-challenging towers?  Yes, I know it's a matter of economics, but to a lot of Asian builders/developers/owners, cost is not the issue.  It's the pride (though some would say the folly) of building high.

<{POST_SNAPBACK}>

In this case it's just the number (date) 1776. I think the US will have a WTB again someday, we must, we started it in 1931 with the Empire State Building and maintained it until the Petronas Towers were built in 1998.

B)

[Spartan]

I keep catching bits and pieecs of this. It sounds to me like it will still be 1776ft tall, but it looks like the actual number of floors will increase. Anyone have some info on that?

Over all I like it better than the previous one. I also wish that they would jsut build the thing. Build the other 5 smaller towers and get SOMETHING moving down there.

[Spartan]

In this case it's just the number (date) 1776. I think the US will have a WTB again someday, we must, we started it in 1931 with the Empire State Building and maintained it until the Petronas Towers were built in 1998.

B)

<{POST_SNAPBACK}>

This plan is marginally better. I think that were should be thinking in terms of meters, not feet

This buliding is obviously designed to mimic the ESB to an extent. While I do think it could be better, this one is acceptable.

[Medo]

Much better than the other Freedom Tower

[Brickell]

I originally voted worse. I think this is uninspired design. At least the last one was unique. I'm warming to this one though, and it's definitely a step up, but still far behind what should be America's top building.

[jazzman]

This plan is marginally better. I think that were should be thinking in terms of meters, not feet

[waccamatt]

It is better, but is still a very boring design. Can we get a Chinese architect to design something cool for us? Does Frank Lloyd Wright have any descendents in architecture?