daily menu » rate the banner | guess the city | one on oneforums map | privacy policy | DMCA | news magazine | posting guidelines

Go Back   SkyscraperCity > World Development News Forums > General Urban Developments > DN Archives



Global Announcement

As a general reminder, please respect others and respect copyrights. Go here to familiarize yourself with our posting policy.


Reply

 
Thread Tools
Old June 20th, 2007, 07:08 PM   #2841
Spandex
Registered User
 
Spandex's Avatar
 
Join Date: Jun 2007
Location: Reykjavik/Milan/Oslo/Súđavík
Posts: 165
Likes (Received): 1

Then the tower will be awesome in the twilights and at sunset, indossing a redish cape
Spandex no está en línea   Reply With Quote

Sponsored Links
Old June 20th, 2007, 07:08 PM   #2842
Wild Thing
Registered User
 
Wild Thing's Avatar
 
Join Date: Jun 2007
Location: Edinburgh
Posts: 12
Likes (Received): 0

Hey folks, first time poster, long time lingerer. Loving Burj Dubai and watching it slowly grow.

So I was wondering, what is the physical limitation for concrete to be built up to before the pressure on the lower levels would just cause it to disintegrate under the immense weight? The pressure must be phenomenal once BD nears it's final height.
Wild Thing no está en línea   Reply With Quote
Old June 20th, 2007, 07:10 PM   #2843
AltinD
The Modecator
 
AltinD's Avatar
 
Join Date: Jul 2004
Location: TIRANA / Dubai / Vienna
Posts: 31,827
Likes (Received): 6071

I'm booooored

[IMG]http://i16.************/6ban8s1.jpg[/IMG]

[IMG]http://i8.************/6d0ro9d.jpg[/IMG]


__________________
I am the eye in the sky, Looking at you
I can read your mind
I am the maker of rules, Dealing with fools
I can cheat you blind.

AltinD no está en línea   Reply With Quote
Old June 20th, 2007, 07:29 PM   #2844
ZZ-II
I love Skyscrapers
 
ZZ-II's Avatar
 
Join Date: May 2006
Location: Near Ingolstadt in Bavaria
Posts: 33,512
Likes (Received): 6535

have u a bigger version Altin i can't see anything
ZZ-II está en línea ahora   Reply With Quote
Old June 20th, 2007, 08:13 PM   #2845
djenk
Registered User
 
djenk's Avatar
 
Join Date: Sep 2006
Location: Rotterdam
Posts: 67
Likes (Received): 0

Quote:
Originally Posted by Wild Thing View Post
Hey folks, first time poster, long time lingerer. Loving Burj Dubai and watching it slowly grow.

So I was wondering, what is the physical limitation for concrete to be built up to before the pressure on the lower levels would just cause it to disintegrate under the immense weight? The pressure must be phenomenal once BD nears it's final height.
Approx 2700 meters (yes, that is 2,7 kilometer) by using grade 53/65 concrete. So failure by exceeding max pressure isn't really an issue. Its stability that counts
__________________
A bad day of diving is still better dan a good day at the office
djenk no está en línea   Reply With Quote
Old June 20th, 2007, 08:14 PM   #2846
vinouz
Registered User
 
Join Date: Mar 2006
Posts: 121
Likes (Received): 1

So, the concrete used in the core, is apparently rated for 80MPa (megapascal).

From onlineconversion.com:
80 megapascal = 815.772 970 382 kilogram-force/square centimeter

so every square centimeter at the base can only support a bit more than 800Kg. How much concrete does that make in itself ?

Another search on google with "concrete density" gives us the answer:
"Typical density of concrete (2.3 g/cm3)" (http://hypertextbook.com/facts/1999/KatrinaJones.shtml)

Let's say that this superstrong concrete is very heavy and assess 4g/cm^3.
That means that every centimeter of height weights 4g concrete on its square centimeter base. That translate into 400g per meter.

So we can guess that we can pour 2000m of concrete on this base.

We were considering a concrete almost two times denser than normal, which of course is overly cautious. But let's use the engineer's overcautious caution and take an additional 100% margin (plan for double the trouble). We can safely estimate a 1000m concrete column.

But that is done considering that the concrete structure is as wide on top than at the base. This, of course, is not the case.

As can easily be seen, the top portion occupies far less surface than the base.
The secret of this building height resides here: its hyperbolic shape. The large base sharing the weight of a smaller top makes than we can overcome even these 1000m concrete limitations.

One additional thing to mention is that the concrete slabs and, more generally, everything inside, adds to the weight of the tower. But this is marginal considered the enormous margins taken here.

In fact, ultimately the problem is not really the weight of the concrete, but the couple exerted on the base by the wind pushing the tower.

That is the reason why the principal limitation of highrises is the width-to-height ratio, and not only the height. If a tower is ten times as high as its base is wide, each newton of pressure exerted on its top translates in ten times the pressure on the perimeter of its base.

Here, for example, the Rose Rotana Hotel is a real engineering feat, I guess, for its height is 333m and its base is 32m giving a heigth to width ratio of 10.4. And the concrete core on which all the lateral pressure is exerted is even thinner, around half that. Here we have a final ratio of around 15-20 to 1, meaning that one kilogram of wind pressure on the top might exert as much as 20 on the concrete base....

Vincent.

Quote:
Originally Posted by Wild Thing View Post
Hey folks, first time poster, long time lingerer. Loving Burj Dubai and watching it slowly grow.

So I was wondering, what is the physical limitation for concrete to be built up to before the pressure on the lower levels would just cause it to disintegrate under the immense weight? The pressure must be phenomenal once BD nears it's final height.
vinouz no está en línea   Reply With Quote
Old June 20th, 2007, 08:29 PM   #2847
djenk
Registered User
 
djenk's Avatar
 
Join Date: Sep 2006
Location: Rotterdam
Posts: 67
Likes (Received): 0



Stating that the additional weight of the floor slabs is marginal is really NOT true. The surface of each floor slab * the thickness quite equals the surface of the wall spanning between 2 floors * the thickness of the walls. So the contribution of both wall and floor is quite equal too.

But on the other hand.... the lower walls of Burj Dubai are really MASSIVE so that all that is mentioned above not really counts for the lower parts.

About the slenderness of buildings: Rose Rotana building must have outriggers that connects the core with the facade columns (like burj dubai, petronas towers and more). The ratio of 1:20 is just way too slender. 1:10 is marvellous enough...
__________________
A bad day of diving is still better dan a good day at the office
djenk no está en línea   Reply With Quote
Old June 20th, 2007, 08:29 PM   #2848
vinouz
Registered User
 
Join Date: Mar 2006
Posts: 121
Likes (Received): 1

Hey, that's great man ! Thank you a lot for going on !

I was wondering, just to adjust tot the lens difference, could you post the exif infos of one of the photos from the previous camera and one of a photo with the new camera, in order to have the focal length and correct the barrel distortion of the first images to better fit with the new ones.

Vincent.

P.S.: BTW, how many megapixel now ;q ?

Quote:
Originally Posted by joobn View Post
hi guys! sorry for the long pause, but i had to buy a new camera as i had thrown my other one away accidently, got a new sony cybershot! its awesome but im scared to put it where its humid so i took a photo inside! Im really sorry about the humidity, its just getting hard to take photos and its a new camera... not risking anything for this one!

Just for scale, not for floor count!

vinouz no está en línea   Reply With Quote
Old June 20th, 2007, 08:32 PM   #2849
Wild Thing
Registered User
 
Wild Thing's Avatar
 
Join Date: Jun 2007
Location: Edinburgh
Posts: 12
Likes (Received): 0

That's fascinating, thanks for answering!
Wild Thing no está en línea   Reply With Quote
Old June 20th, 2007, 08:37 PM   #2850
AltinD
The Modecator
 
AltinD's Avatar
 
Join Date: Jul 2004
Location: TIRANA / Dubai / Vienna
Posts: 31,827
Likes (Received): 6071

Quote:
Originally Posted by ZZ-II View Post
have u a bigger version Altin i can't see anything
Bigger versions for proffesionals only (with AutoCad)
__________________
I am the eye in the sky, Looking at you
I can read your mind
I am the maker of rules, Dealing with fools
I can cheat you blind.

AltinD no está en línea   Reply With Quote
Old June 20th, 2007, 08:48 PM   #2851
historybuffer
Registered User
 
Join Date: Jan 2006
Posts: 546
Likes (Received): 5

I'm just waiting patiently for heights where the International Space station can dock at the top floors. I guess I'll just have to keeping waiting and waiting.



In western culture the middle finger represents a gesture of offense.
Doesn't it seem with these supertalls that skylines around seemed overly
diminutive, and the supertall is the city's middle finger at the rest of the world for the next few months while somewhere in South Korea or Communist China architects, and speculators look to develop the next
world's tallest building??? I thought this fad died a useful death when the Sears Tower in Chicago was bought buy Japanese businessmen in the 1980s. How did we get back to this nonsense again? No offense to this fine edifice in Dubai just a statement in general about this global pre-occupation with the "world's tallest building."
historybuffer no está en línea   Reply With Quote
Old June 20th, 2007, 08:50 PM   #2852
AltinD
The Modecator
 
AltinD's Avatar
 
Join Date: Jul 2004
Location: TIRANA / Dubai / Vienna
Posts: 31,827
Likes (Received): 6071

You are sooooo 2004
__________________
I am the eye in the sky, Looking at you
I can read your mind
I am the maker of rules, Dealing with fools
I can cheat you blind.

AltinD no está en línea   Reply With Quote
Old June 20th, 2007, 08:55 PM   #2853
historybuffer
Registered User
 
Join Date: Jan 2006
Posts: 546
Likes (Received): 5

??? That was a riotous non-sequitor.


Wait what's that?

Beep, beep beep look ladies and gentlemen the Space Shuttle is docking at the top
of the "World's Tallest Building" a fine sight to behold in this greatest of world cities the city of

_______________________.

(enter name of city)

Last edited by historybuffer; June 20th, 2007 at 09:04 PM.
historybuffer no está en línea   Reply With Quote
Old June 20th, 2007, 08:57 PM   #2854
AltinD
The Modecator
 
AltinD's Avatar
 
Join Date: Jul 2004
Location: TIRANA / Dubai / Vienna
Posts: 31,827
Likes (Received): 6071

Then go back to study past gone history, and let us here discuss the FUTURE.
__________________
I am the eye in the sky, Looking at you
I can read your mind
I am the maker of rules, Dealing with fools
I can cheat you blind.

AltinD no está en línea   Reply With Quote
Old June 20th, 2007, 10:42 PM   #2855
Edwin_kok86
Registered User
 
Edwin_kok86's Avatar
 
Join Date: May 2006
Location: Haarlem
Posts: 105
Likes (Received): 0

AltinD, do you have the Autocad .dwg file of the picture you showed? because i,m a architect student and would like to see it in .dwg and tell some more about it.
__________________
Schalkstad...the new heart of Haarlem
Edwin_kok86 no está en línea   Reply With Quote
Old June 20th, 2007, 10:57 PM   #2856
paul.c.martens
Registered User
 
paul.c.martens's Avatar
 
Join Date: Oct 2006
Posts: 204
Likes (Received): 4

I'd be willing to host the file (doesn't seem very large).
paul.c.martens no está en línea   Reply With Quote
Old June 20th, 2007, 11:40 PM   #2857
JuanPaulo
Guayaquil Vive Por Ti!
 
JuanPaulo's Avatar
 
Join Date: Feb 2004
Location: Honolulu, Hawai'i
Posts: 20,817
Likes (Received): 31846

I'm a structural engineer and have access to AutoCad. I would love to get the dwg file also!!!
JuanPaulo no está en línea   Reply With Quote
Old June 21st, 2007, 12:37 AM   #2858
FM 2258
Registered User
 
FM 2258's Avatar
 
Join Date: Jan 2004
Location: Austin
Posts: 5,436
Likes (Received): 611

Quote:
Originally Posted by AltinD View Post
I'm booooored



Me too. I was about to ask how hot it was in Dubai since it looked hot in those pictures when I realized Weather.com had the answer.







95 F at night, feels like 107? Insane!!!!!!
FM 2258 no está en línea   Reply With Quote
Old June 21st, 2007, 12:40 AM   #2859
BlackSmith!
Peace sells...
 
BlackSmith!'s Avatar
 
Join Date: Dec 2006
Location: Ajdovščina
Posts: 786
Likes (Received): 6

There are also some other free programs which open dwg files. I use free dwg viewer - google it
BlackSmith! no está en línea   Reply With Quote
Old June 21st, 2007, 01:16 AM   #2860
The-Real-Link
The-Real-Link!!
 
The-Real-Link's Avatar
 
Join Date: Oct 2004
Posts: 754
Likes (Received): 300

I've also worked with AutoCAD extensively in my studies. I should have no problem opening the files.
The-Real-Link no está en línea   Reply With Quote


Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Related topics on SkyscraperCity


All times are GMT +2. The time now is 09:28 PM.


Powered by vBulletin® Version 3.8.11 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions Inc.
Feedback Buttons provided by Advanced Post Thanks / Like (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

SkyscraperCity ☆ In Urbanity We trust ☆ about us | privacy policy | DMCA policy

Hosted by Blacksun, dedicated to this site too!
Forum server management by DaiTengu