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Old April 5th, 2008, 03:11 PM   #4221
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Originally Posted by Msradell View Post
I've asked the same question several times and no one has answered. It seems like people don't want to admit that Freedom Tower will not truly be 1776' tall. I agree with your view of the matter, the original design with the integral spire was 1776' but this one with the antenna stuck on top IS'NT'

It's a pet peeve of mine too. Many of these 1600ft + buildings simply aren't that tall IMO. But in the view of those who matter, if an antenna looks and smells like a spire it counts. Go figure.


I don't think this building is anywhere near 1776 ft but my opinion doesn't matter. They stick a hypodermic needle on top of a 1300 footer, make the needle have some architectural features and boom, there you go, 1776 feet. It's a joke, but it is the way it is. The folks who are the powers that be have decided those feet count so I guess they do.

I'm just pleased that some of these monsters that are being built around the world will actually be functional all the way up, like Chicago Spire to name one and Shanghai WFC to name another.
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Old April 5th, 2008, 06:24 PM   #4222
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Definitive Answer

Strategy for Seven World Trade Center Exceeds Expectations

September 12, 2005

At the dawn of a marketing blitz for tenants to join him in the first office tower to rise from Ground Zero, Seven World Trade Center developer Larry Silverstein is all gab about the souped-up-for-more-safety features of the 52-story replacement for the tower that collapsed on Sept. 11, 2001, after sustaining collateral damage from attacks on the WTC’s twin towers. But to the builders of the new 1.7-million-sq-ft high-rise, the job stands out for a completely different reason. By building the tower’s steel frame ahead of its structural concrete core, the team managed to beat its own predictions for a reduced schedule by a month. By demanding cooperation among trades, the approach breaks the norm for construction in New York City in an "extraordinarily" positive way, say sources. And, that is no mean accomplishment.

Steel ahead of concrete turned out to be so successful that, after much initial resistance, Silverstein Properties Inc. gave the green light to use the same approach on its planned 1,776-ft-tall Freedom Tower across Vesey Street. "The construction method for 7 is exactly what we’ll be using on the Freedom Tower," says Carl Galioto, technical partner in the New York City office of the architect for both 7 and the Freedom Tower, Skidmore, Owings & Merrill.


During planning for 7, the construction manager predicted the strategy would shorten the schedule by three to four months. "There was a lot of skepticism within our ranks about the steel-first method and the client was not sure it was the best way to go," says Elio Cettina, supervisor of general superintendents for Tishman Construction Corp. of New York. The CM also is building the Freedom Tower.

The proof is in the pudding, says Cettina. "We were able to maintain four-day-per-floor cycles for all operations" and beat the clock by a month beyond the prediction, he says.
Steel topped out last October instead of in November. Substantial completion is targeted for early November. Silverstein plans to move into its space in March.

The steel-first approach requires meticulous planning and added doses of coordination and communication among the major contractors. It also requires buy-in by the trades, especially ironworkers. "It really took a big team effort," which is a switch from the usual adversarial atmosphere, says Dominick D’Antonio, chief engineer for the steel contractor, Helmark Steel Inc., Wilmington, Del.

The structural engineer still thinks concrete first is the better way to go. There is no need for erection columns and other temporary steel to stabilize the frame laterally until the core, which provides the structure’s permanent lateral stability, catches up, says Silvian Marcus, CEO for WSP Cantor Seinuk, which engineered the original 7 and also is designing the Freedom Tower. With concrete first, there also is no need for extra temporary protection.

The methodology’s advantages far outweigh any disadvantages, claims Mel Ruffini, Tishman’s project executive. Steel first allows the concrete to be cast inside a protective frame. It is considered safer, and thus acceptable to New York City ironworkers, who will not allow other work overhead. Steel first also allows the curtain wall to start sooner. And it is a more sustainable approach because the self-climbing forms used for the concrete core are reusable, says Tishman.

The concrete contractor credits the self-climbers for much of the success of the method. It would have taken almost twice as long to complete a floor with a hand-set system, says William Kell, chief estimator-project manager for the concrete contractor, Sorbara Construction Corp., Lynbrook, N.Y. That would have had concrete work lagging too far behind steel work. Tishman says the self-climbers have not been used in New York City for an office building.
The steel-first approach in New York City is not new. The engineer had used it first in the late 1960s on two office towers and recently on two more. But none of the buildings used self-climbers. On 7, "they literally had to design the building around the forming system," says Kell.

Power Pedestal

The glass-clad office tower, 213 x 171 ft in plan, sits on a utility power substation, framed in concrete–also a replacement. Only the tower core and lobby "corridor" penetrate the substation. Tower mechanical floors begin 78 ft above grade. The first office floor is 125 ft above grade.

The new substation and tower jobs, designed and managed by the same firms, share foundations. Tower core walls take loads to caissons 15 to 20 ft below the water table. The engineer was able to reuse 30% of the original 7’s caissons.

Work on the office tower could not proceed until the substation was topped out in October 2003. Work was complicated and delayed by obstructions encountered during foundation work.

In essence, workers initially built two independent structures. The first was a parallelepiped-shaped steel frame, like a warped doughnut. The second was a rectilinear core, 108 ft on side, which filled the doughnut hole.


Sequence. All operations, starting with steel erection, followed a four-day-per-floor cycle at 7 WTC. Sequence required meticulous planning.
Steel erection for 7 had to follow the substation frame. Helmark and Falcon Steel Co., its Forth Worth, Texas-based erector, had never done a steel-first, hybrid-system building. Despite a learning curve, the system "proved out," says D’Antonio.

The doughnut’s lack of lateral stability was compounded by forces imposed by two tower cranes and other construction equipment. To counter this, Helmark temporarily braced 12 bays. Bracing overlapped the concrete operation by four floors to facilitate the transfer of lateral loads into the permanent system, says D’Antonio. There also was a temporary floor system of steel joists and deck panels to cover the core void, and safety nets to protect workers.

Temporary steel was erected along with the permanent frame. The operation was conventional except for moving the void cover and netting; jumping 14-story steel stair towers, also temporary; and removing and relocating temporary bracing as the steel went up.

There were as many as 16 to 18 floors of temporary bracing. "We erected, unerected and re-erected temporary steel three times," says D’Antonio.

D’Antonio does not know whether there was a time penalty for erecting and moving the 1,000 tons of temporary steel within the 12,000-ton frame.

There could be no fewer than eight and no more than 12 floors from the steel work floor to the top-most poured and cured core section. "We had to stay on a very tight schedule with the concrete contractor," says D’Antonio. "We could not go too fast or too slowly."

After the substation was topped out, ironworkers mobilized cranes and erected embedded steel columns around the core void. Then, the steel operation demobilized for about a month so that Sorbara could mobilize the self-climbers. It was the only interruption in the flow.

Four-Day Floors

After the formwork was in, the four-day-per-floor cycle began with steel erection. Metal deck followed, with its concrete topping. Workers then cast core shear walls and slabs. Next came the steel’s sprayed-on fireproofing. The remaining trades followed. This included curtain-wall work, mechanical, electrical and plumbing work, elevators and interior work.

The shear-wall operation began its first cycle after the steel frame was eight floors up and concrete had been placed on the metal deck a few floors overhead. First, the inside face of the form was fixed off the climbing work platform. Workers installed bulkheads off of the inside form and frame reinforcing steel. The form’s outside face was raised with chain falls and the forms were closed. Then, concrete was cast. Workers stripped forms the next day. The self-climber platform was jacked and inside forms reset. Once the trailing platforms hanging from the self-climbers were a few floors above, floor slabs were conventionally constructed.

The construction of the original 7 was described as a logistical nightmare by its designers and builders (ENR 11/28/85 p. 30). The 9/11 terrorist attacks ended up causing another nightmare. But according to the new team, which includes the same structural engineer and CM, the design and construction of the new 7 was made simpler because of the opportunity to integrate the substation design and construction with the tower above it. Both jobs were equally difficult because major utilities in all surrounding streets ripped open because of post-9/11 work.

Work also was complicated by neighboring projects to restore buildings damaged on 9/11, and nearby road work. To handle the congestion, access problems and staging limitations, Tishman had weekly coordination meetings with the power utility, the phone company, city and state transportation departments and the city’s transit authority. "Everyone worked in a checkerboard fashion, leapfrogging around each other," says Ruffini.

Larry Silverstein boasts that 7 will be the safest commercial office building in the U.S., until the Freedom Tower is built. "Miraculously, the structure of 7 and the life-safety enhancements parallel the recommendations" made in June by the National Institute of Standards and Technology in its $16-million report on the World Trade Center, says Silverstein. "We anticipated this by about three years," he says.

Going Further

Core in Core. Emergency access core within Freedom Tower’s main core will provide dedicated and protected elevators for firefighters, and more. Image Courtesy of Skidore Owings and Merrill LLP Each subsequent building in the WTC redevelopment will be designed using the same principles, Silverstein says. Plans for the Freedom Tower go further. It will have a concrete-enclosed emergency access core within the concrete core.
The EAC is designed to contain five service elevators, protected so that equipment will be able to resist water. The service lobby would be pressurized to mitigate smoke intrusion, either on the floor or in hoistways. The elevators and pressurized stairs would be dedicated for use by emergency responders. If an incident is on the 50th floor, firefighters will take the elevator to 48 and walk up, says Galioto. Elevators also would be used to evacuate those with disabilities. The EAC would contain the electrical and com-munications closets for emergency services.

The Freedom Tower project lost about eight months when the city police came up with new security rules for standoff distances after New York Gov. George E. Pataki decided West Street alongside the WTC site would remain a surface street. That meant going back to the drawing board. A new design concept was released in June (ENR 7/11 p. 10).

SOM plans to complete schematic design by year-end. Foundation packages should be issued before that so construction can commence in the first quarter of next year, says Galioto. That should "maintain the governor's...schedule" for occupancy of the building in the spring of 2010, he says.

Silverstein calls the need to redesign a "frustrating" experience. He says his biggest regret in the last year was the "lack of coordination relative to the New York Police Dept. and security issues on the site. We lost time and encountered a good deal of additional cost," he says. Silverstein has not yet tallied the toll, but probably will seek reimbursement from the city or state.

For Tishman, it was not a total loss. Some of the planning and all of the relationships developed, especially with the Port Authority of New York and New Jersey, which owns the land and runs the PATH subway that runs under the site. But the team had to throw out lots of work.

Silverstein and SOM think the new design beats the first. "It responds to an even greater variety of issues," says Galioto. "We’re eager to proceed."

Nadine M. Post , Engineering News-Record
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Old April 5th, 2008, 07:39 PM   #4223
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So if they were able to build one floor in four days for 7, then we should expect about one floor in about six days for the Freedom Tower. 7WTC is like a protype for 1, but 1WTC is even bigger with a stronger and larger core, and I suspect it will take a tad longer since every floor is totally different from one above and below it.
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Old April 6th, 2008, 03:50 AM   #4224
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Quote:
Originally Posted by FlyFish View Post
It's a pet peeve of mine too. Many of these 1600ft + buildings simply aren't that tall IMO. But in the view of those who matter, if an antenna looks and smells like a spire it counts. Go figure.


I don't think this building is anywhere near 1776 ft but my opinion doesn't matter. They stick a hypodermic needle on top of a 1300 footer, make the needle have some architectural features and boom, there you go, 1776 feet. It's a joke, but it is the way it is. The folks who are the powers that be have decided those feet count so I guess they do.

I'm just pleased that some of these monsters that are being built around the world will actually be functional all the way up, like Chicago Spire to name one and Shanghai WFC to name another.
Quote:
Originally Posted by Msradell View Post
I've asked the same question several times and no one has answered. It seems like people don't want to admit that Freedom Tower will not truly be 1776' tall. I agree with your view of the matter, the original design with the integral spire was 1776' but this one with the antenna stuck on top IS'NT'
Alright Guys, I think we can settle this doubt over the true height of the Freedom Tower. I did some digging and found this info on wiki about the four categories which the CTBUH measures the height of buildings.

(From Wikipedia)
Pinnacle Height/Spire Height: the height from the sidewalk level of the building to the architectural top of the tower. This vague definition can lead to confusion, but basically any structure beyond occupiable floors that is architecturally significant in its design and structurally integrated into its height is considered a spire. A spire and an antenna can sometimes coincide, as in the new design for Freedom Tower, but generally they do not.

Feel free to comment
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Old April 6th, 2008, 04:48 AM   #4225
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Originally Posted by Infrasuper Planet View Post
Alright Guys, I think we can settle this doubt over the true height of the Freedom Tower. I did some digging and found this info on wiki about the four categories which the CTBUH measures the height of buildings.

(From Wikipedia)
Pinnacle Height/Spire Height: the height from the sidewalk level of the building to the architectural top of the tower. This vague definition can lead to confusion, but basically any structure beyond occupiable floors that is architecturally significant in its design and structurally integrated into its height is considered a spire. A spire and an antenna can sometimes coincide, as in the new design for Freedom Tower, but generally they do not.

Feel free to comment
I've read that description before, all it seems to do is add confusion. Who makes a decision if it is architecturally significant to the building? IMHO what is on top of Freedom Tower is just an antenna. The only thing architecturally significant about it is that it makes the building 1776' tall. The spire in the original designed was an integral part of the architecture, this one isn't.
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Old April 6th, 2008, 05:46 AM   #4226
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Quote:
Originally Posted by Msradell View Post
I've read that description before, all it seems to do is add confusion. Who makes a decision if it is architecturally significant to the building? IMHO what is on top of Freedom Tower is just an antenna. The only thing architecturally significant about it is that it makes the building 1776' tall. The spire in the original designed was an integral part of the architecture, this one isn't.
For you it isn't, for me it is. So who is right?
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Old April 6th, 2008, 06:21 AM   #4227
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Quote:
Originally Posted by Msradell View Post
I've read that description before, all it seems to do is add confusion. Who makes a decision if it is architecturally significant to the building? IMHO what is on top of Freedom Tower is just an antenna. The only thing architecturally significant about it is that it makes the building 1776' tall. The spire in the original designed was an integral part of the architecture, this one isn't.
I don't think the question is whether it is architectually significant or not. This is the CTBUH way of making their definition of what counts sound really thought out but it isn't. The real question is what is an antenna? Whatever isn't an antenna is a spire.

In this case, the 'spire' is being built with the option of housing an antenna inside of it. So I suppose this isn't truely an antenna, but some of you will still argue it is.

Regardless it is still a tall building. I don't see why all of you are getting your panties in a bunch because of 300 feet and the fact that even if it didn't have a spire/antenna one would sitll be added on to the top of the building.
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Old April 6th, 2008, 10:38 AM   #4228
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all fom flickr by totempolar.
thanks to him/her for uploading


Prospective WTC Development Plans
image hosted on flickr

image hosted on flickr



WTC1 Ground Zero
image hosted on flickr

image hosted on flickr
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Old April 6th, 2008, 12:05 PM   #4229
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the last two pics give a good overview how far the progress is on the tower, many thx for posting them
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Old April 6th, 2008, 01:51 PM   #4230
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No one has ever found the reason behind that skinny column yet.
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Old April 6th, 2008, 02:43 PM   #4231
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No one has ever found the reason behind that skinny column yet.
From what I have read, the skinny column provides additional support for the main entrance of the tower. The top of the column will be just below your feet when you walk into the building...

The pictures show that there are forms everywhere and that there is alot of floor work going on but it does appear that they are doing little work on finishing the next level of the core. You would think that the core needs to rise soon if they're going to reach street level by early summer.
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Old April 6th, 2008, 04:41 PM   #4232
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That construction site looks complex
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Old April 6th, 2008, 06:56 PM   #4233
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From what I have read, the skinny column provides additional support for the main entrance of the tower. The top of the column will be just below your feet when you walk into the building...

The pictures show that there are forms everywhere and that there is alot of floor work going on but it does appear that they are doing little work on finishing the next level of the core. You would think that the core needs to rise soon if they're going to reach street level by early summer.


The southern half of the core IS rising faster. Hopefully, by early to mid June, both halves should be at street level.
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Old April 7th, 2008, 02:29 AM   #4234
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Getting back on topic, an article appears in today's edition of the Daily News.

It says that security at the Freedom Tower and the rest of Ground Zero will be so tight that it'll be like trying to enter Fort Appachi or a bank vault!

For the full story, please go to; http://www.NYDailyNews.com .
Man. The NYPD can go screw off for even DRAFTING a plan like that. That would just destroy commerce in Lower Manhattan.
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Old April 7th, 2008, 03:35 AM   #4235
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In fact, to add to the Freedom Tower core debate, I think it just may be NYC law that the steel of a skyscraper always must rise first. Does anyone know if it's true or not, or is it just a tradition, or perhaps an outdated law that is still followed?
not sure where you got that idea. walk by the site of 11 times square (42nd and 8th) for a counterexample.
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Old April 7th, 2008, 04:16 AM   #4236
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I think hes talking about this unspoken of agreement between steel and concrete companies in construction in New York. But like you stated 11 TS is going core first for the first few floors and so will 1 WTC.
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Old April 7th, 2008, 04:32 AM   #4237
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But how can that be true if the steel is already ahead of the concrete and it's fact that the steel will go up first?
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Old April 7th, 2008, 04:37 AM   #4238
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Well it maybe fact according to you, but you have yet to show where it says steel will be first and the only reason that steel is ahead right now is because of the nature of the construction of the lower floors. I imagine the amount of rebar that is being put in to the northern core in order to rise another level is insane because of the PATH tracks. Once it gets over that hump the core will rise much faster than the steel.
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Old April 7th, 2008, 04:39 AM   #4239
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"Steel ahead of concrete turned out to be so successful that, after much initial resistance, Silverstein Properties Inc. gave the green light to use the same approach on its planned 1,776-ft-tall Freedom Tower across Vesey Street. "The construction method for 7 is exactly what we’ll be using on the Freedom Tower," says Carl Galioto, technical partner in the New York City office of the architect for both 7 and the Freedom Tower, Skidmore, Owings & Merrill."


Perhaps one of the few exceptions is 11TS, but I don't think so since 7WTC once looked like 11TS, with nothing but a core, but as it got taller, and as the steel was erected, it, the steel, was always ahead of the concrete core, except for when there was no steel, obviously.

I think there is only one tall skyscraper in NYC made of nothing but concrete, save stuff like the rebarb, and I think it's the Carnegie Hall Tower.



But I'm quite happy that steel is used in almost every skyscraper here. Paired with the reinforced concrete core in the right way, you can make great and nearly invincible buildings. Exposed steel will almost always look better than exposed concrete, like, for example, the visible beams on the FT's base, the structure of 3WTC, Silvercup West, MoMA Spire, SWFC, ect, steel is the best.

Last edited by Ebola; April 7th, 2008 at 04:57 AM.
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Old April 7th, 2008, 09:26 AM   #4240
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OK I choose the freedom tower as my first post. I'm in luv with this tower. I've been reading these thread for a long time now. I'm sure someone here will tell me how not to talk about Dubi or how slow this project is going. And all I have to say about all that noise is. I was born in New York (Brooklyn stand-up). And Dubi is a great city but I'm not in luv with it. And the project is moving just fine for me. The bed-rock on the island is pretty damn tough and lets not forget what happen on this land.

Now I'm not sure what it take to build these amazing building and by that I mean all supertalls. But I'm willing to sit and learn. Now I'm sure that sounds pretty damn crazy but it's early And I haven't been to sleep so my brain really isn't working right. Thanks SCC
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