Arthur Dent wrote:More reasonably sized tall buildings already sway enough in the wind to make some people feel sea sick. I can only image what it will be like in that building.
I work with one of the former structural engineers of this building. He's one of 3 people in the world who actually knows the final height of the building. (No, he can't tell anyone.)
As for the sway, the shape of the building mitigates a lot of the wind forces. For a really geeky article about this building, check out this link:
Larry Novak, an associate director at SOM says that the structure of the Trump Tower in Chicago, (which SOM also designed) is different than the Burj Dubai because its column lines shift as the building steps in, requiring transfer beams to carry the load from one column line to the next (see the June 2007 CONCRETE CONSTRUCTION cover article “Reaching New Heights in Chicago”). For the Burj Dubai, the columns are in line to the top of the structure. As the building floor plan diminishes in size, column lines terminate. There are 27 such reductions in floor size to control wind shear and vortex shedding.
I wondered that (about the Trump Tower in Chicago) as soon as I started reading this article. I was walking past it the other day and was surprised to see it's innards made of concrete. I thought that whatever that octagonal building near the Sears Tower, the one with the big bright glass atrium on top, was the world's tallest concrete building. When I saw Trump Tower I thought to myself, "there must have been advances in concrete technology since they built that."
Arthur Dent wrote:More reasonably sized tall buildings already sway enough in the wind to make some people feel sea sick. I can only image what it will be like in that building.
I work with one of the former structural engineers of this building. He's one of 3 people in the world who actually knows the final height of the building. (No, he can't tell anyone.)
As for the sway, the shape of the building mitigates a lot of the wind forces. For a really geeky article about this building, check out this link:
Great article. Thanks for sharing. I don't know very much about structural engineering, but I thought that it wasn't possible to build very tall buildings based on a concrete frame. Obviously, I am behind the times.
I'm curious about this:
"There is no post-tension (PT) reinforcement used anywhere in the building."
There must be pre-tensioning then, right? I thought the big weakness of concrete that makes it difficult for framing was its weakness in tension. I thought pre-tensioning had to be done in a dedicated facility with hydraulic presses and the like. You can't poor these beam on site, but have to use haul already manufactured beams up with a crane (which they say they aren't doing). Am I totally confused about this?
Also, how do people get in and out of such a huge building? The ground floor must be 100% elevators.
Well, G. Keenan is right, there have been advances in concrete frame technology. And, believe it or not, Trump is partially to thank for its acceptance. His high-rise in Chicago, and hotel in Las Vegas, and another building that's going up in FL are all concrete frame. Why? Because your floor depth is thinner, so you can have more floors for the (total) height. That means more money (rent or sales) per building. I mean, why else would Trump do it?
Arthur: While I work with structural engineers, I am not one. However, I do know this much. Advances in admixtures and fibers are contributing to some of this increased capability. For example:
The original design for the Chicago Trump Tower (the one G walked by) called for it to be the tallest building in the US. They designed the concrete to a strength of approximately 20,000 psi. I have a thin slice of a test sample on my desk, as we made them into coasters. I don't have the exact numbers on me, but the coaster can hold something like 13,000 lbs. (I'll put the correct number in this post when I get back in the office on Monday.)
The tension statement is still applicable, though. But the amount of reinforcing steel is massive, and combined with the aforementioned additives, you get the best of the tension and compression worlds.
Last edited by mikechamp on March 27 08, 9:42 pm, edited 1 time in total.
I am suspicious of anything that seems unnatural with growth patterns. I was suspicious of the tech stocks as they soared for reasons that seemed to defy logic, I was suspicious of the real estate boom when it seemed like they were building and buying with nobody in the places for sale yet.
I think the same as Dubai. I just wonder in 10 years those islands will be uninhabited and those skyscrapers empty.
The engineering aspect is amazing but I can't help but believe these sort of incredibly excessive displays of conspicuous consumption aren't great for the world.
It would be nice- and a fantasy- if those in charge cared about the women of Dubai just a fraction as much.
lukethedrifter wrote:The engineering aspect is amazing but I can't help but believe these sort of incredibly excessive displays of conspicuous consumption aren't great for the world.
It would be nice- and a fantasy- if those in charge cared about the women of Dubai just a fraction as much.
Thanks for the link. I've read a few articles documenting the Human Rights violations going on in Dubai. Those buildings aren't going up for free and the workers (a majority of whom are migrant workers) aren't treated particularly well.
The engineering is astonishing, but I'm with Jim on the list of places I'd wish to visit.
lukethedrifter wrote:The engineering aspect is amazing but I can't help but believe these sort of incredibly excessive displays of conspicuous consumption aren't great for the world.
It would be nice- and a fantasy- if those in charge cared about the women of Dubai just a fraction as much.
jim wrote:
That hits it on the head with me luke. And you just know it's going to come back and bite them.
They have to do something to plan for when their oil runs out. Their strategy seems to be to turn Dubai into a tourist attraction and financial hub. Seems reasonable to me.
I do wonder about the sustainability of these massive projects in such an arid place though.
