Chicago - John Hancock Center - by Skidmore, Owings & Merrill

[ddny]

Architect: Skidmore, Owings & Merrill LLP

Year: 1969

Style: Modern

Description: The X bracings on this mixed-use building eliminated the need for inner support beams.

http://mywebpage.netscape.com/DDNY%20%20Y2K/john+hancock/john6.jpg

http://mywebpage.netscape.com/DDNY%20%20Y2K/john+hancock/john1.jpg

http://mywebpage.netscape.com/DDNY%20%20Y2K/john+hancock/john2.jpg

http://mywebpage.netscape.com/DDNY%20%20Y2K/john+hancock/john3.jpg

http://mywebpage.netscape.com/DDNY%20%20Y2K/john+hancock/john4.jpg

http://mywebpage.netscape.com/DDNY%20%20Y2K/john+hancock/john5.jpg

http://mywebpage.netscape.com/DDNY%20%20Y2K/john+hancock/john7.jpg

http://mywebpage.netscape.com/DDNY%20%20Y2K/john+hancock/john8.jpg

http://mywebpage.netscape.com/DDNY%20%20Y2K/john+hancock/john9.jpg

[DominicanoNYC]

I wonder why this form of construction isn't used more often.

[Fabb]

One of the best of the best. Thanks ddny.


I wonder why this form of construction isn't used more often.

So do I.
Maybe because it blocks the view from some windows, but that's not very convincing.

[dbhstockton]

It's being used on Times Square Tower.

[DominicanoNYC]

Quote: from dbhstockton on 1:31 pm on June 1, 2003
It's being used on Times Square Tower.
Good. It makes the building much stronger.

[dbhstockton]

Maximises column-less floorspace on a tight lot. *It's not used too often because it often ruins a lot of views.

[Chicagoan]

The diagonal bracing on Big John are there to tie the exterior columns together and serve as wind bracing.

As you guys know, the Hancock is a tube structure. In order for it to be an effective system, columns have to be spaced fairly close, no more than 15'-0". This was not the case in Hancock because they had to maximize views. Thus came the diagonals. The floors are framed conventionally. Both Bunscaft and Fahzlur Kahn spoke of this in seperate interviews.

Sears had a similar problem due to column spacing, but that was resolved by bundling nine tubes together. The Aon Building ( nee Amoco, nee Standard Oil) had none of this because the exterior columns are spaces very close. I was on the 35th floor to meet with a client and it is very cavernous, unlike Hancock ( Which I have been in) or, I assume, Sears ( which I have not).

[Liz L]

I read somewhere that rents are actually higher in the offices or apartments that have bracing across windows, since the cross-bracing is a unique feature... :D...Hat-tip to the cleverness of real-estate development folks!

[ablarc]

Another reason this system is not more often used is that it does not naturally encourage setbacks or any but the simplest overall building configuration.

[Freedom Tower]

Does it really make it stronger though? That's what they said the supports of the WTC would do. However, we all know what happened there. In addition, the ESB was once struck by a plane and it survived. It has the traditional structure of the columns on the inside. Do these types of tubular support systems really make it stronger?

[Chicagoan]

Does it really make it stronger though? That's what they said the supports of the WTC would do. However, we all know what happened there. In addition, the ESB was once struck by a plane and it survived. It has the traditional structure of the columns on the inside. Do these types of tubular support systems really make it stronger?

Only computer models could tell us this. In "Men of Steel" several ideas thrown out was that had the WTC been braced, like the Hancock, it would not have sufferred total collapse. You can make models with balsa and see this in action. But at the same time, a tower that did not have the closely spaced exterior columns and deep spandrels like the WTC would have sufferred some form of collapse immediately after the impact of the planes.

[JonY]

Becoming big fan of ddny's pics 8) Visited the Central Park Buildings' thread a couple of times now.

I had always thought the bracing pertained only to the wind forces rather than the dead weight of the structure. Yet as Chicagoan has pointed out, it was to kill another birdie with one stone re to tie the exterior columns together.

Sears is also wonderful and has had a few reasonable replicas built emmulating it - John Hancock, there is only one identifiable John Hancock.

Bracing of kinds seemed to be popular on the drawing boards from the mid-60s to the early 70s (thereabouts):

Reanaissance Tower in Dallas (Architects Hellmouth, Obata, Kassabaum, completed 1974 - I believe this is decorative rather than structural:

http://www.skyscrapers.com/files/transfer/6/2000/07/124268.jpg

We can however see the influence of J.H. on BHP House, Melbourne as S.O.M. were consultants to architects Yuncken Freeman (with cuter bracing :wink: ):

http://www.skyscrapercity.com/photopost/data/510/3791401_1_.jpg

[TLOZ Link5]

It's being used on Times Square Tower.

And on Citicorp Center. The braces obviously aren't exposed, though.

[Fabb]

Right.
I think they are V-braces instead of X-braces.

[TLOZ Link5]

Bah. I meant diagonal braces in general, not necessarily X-bracing.

Stop being so particular :P

[Chicagoan]

Right.
I think they are V-braces instead of X-braces.

They are sometimes called chevrons- either upright or down facing. Also, there is also K-bracing, which is probably used more that the previous ones.

The braces on Citicorp also carry some of the gravity loads, channeling them onto the mid-plane columns.

[JonY]

External truss-bracing has been placed on the facade on Sydney's Capita Centre,
completed 1989. Architect Harry Seidler. Also showing the large voids:

http://skyscraperphotos.com/cit/dsy02/b/izsy242.jpg_http://www.arch.usyd.edu.au/kcdc/caut/html/CCen/images/CCen1.jpg

[JMGarcia]

Alcoa building San Francisco. Very John Hancock.

http://www.bluffton.edu/~sullivanm/somsf/alcoa.jpg

[JonY]

Of course JM Garcia, they were designed by the same archiitects - read on.

The John Hancock Tower is 1,096ft to roof whereas San Francisco's Alcoa Building,
also known as One Maritme Plaza is 395ft to roof and was completed in 1964 -
basically J.H. is approx. higher by x 2.75.

Both towers were designed by Skidmore, Owings and Merril LLP.

A larger pic of the Alcoa Builidng as previouly mentioned above,
also known as One Maritme Plaza:

http://www.mistersf.com/images/onemaritime02.jpg

A small detail below of the X bracing:

_________________http://www.mistersf.com/images/onemaritime01.jpg

& a pic of it in the early evening:

http://www.equityoffice.com/images/ONEMARIT-L.jpg

[JMGarcia]

It never ceases to amaze me what the proper light can do for a building.

http://www.equityoffice.com/images/ONEMARIT-L.jpg

[JonY]

Most indeedly-doodly JMGarcia :D