Twisted high-rise
Twisted high-rise
(OP)
All,
Just a general question that came to mind as I was reading today of a high rise residential tower that opened in Dubai, where each floor has a 1.5 degree twist from the floor below. this results in a total of 90 degrees of twist top to bottom. Quite a striking structure. It struck me that the connections floor to floor must be quite different from a normal vertical load transfer connection. Is there large lateral components to the loads as these connections get further skewed as the twist increases?
Just a curious non-structural engineer admiring advances in engineering.
Regards,
EEJAIME
Just a general question that came to mind as I was reading today of a high rise residential tower that opened in Dubai, where each floor has a 1.5 degree twist from the floor below. this results in a total of 90 degrees of twist top to bottom. Quite a striking structure. It struck me that the connections floor to floor must be quite different from a normal vertical load transfer connection. Is there large lateral components to the loads as these connections get further skewed as the twist increases?
Just a curious non-structural engineer admiring advances in engineering.
Regards,
EEJAIME






RE: Twisted high-rise
Mike McCann
MMC Engineering
RE: Twisted high-rise
Worked on a team for the LAX Tom Bradley Terminal expansion with enormous, "wave" shaped moment frames that spanned large distances with a radiused top member and framed a 90 foot atrium. The structural guys had to build huge scale models and have them shaker table tested just to prove the structure to the AHJ as there were no historical data or information in the Code to justify the connections and member sizes. I remember the SEOR pulling his hair out after many meetings. Do all SE's walk out of meetings shaking their heads and mumbling?
Regards,
EEJaime
RE: Twisted high-rise
Mike McCann
MMC Engineering
RE: Twisted high-rise
RE: Twisted high-rise
Now THAT is funny. Runs meetings like a kindergarten class. Amazing.
EEJaime
RE: Twisted high-rise
RE: Twisted high-rise
It's easy to draw structures with irregular shapes that looks pretty but to prove it will be stable thru calcultion and math...
RE: Twisted high-rise
RE: Twisted high-rise
RE: Twisted high-rise
http://www.cement.org/buildings/buildings_mixed_in...
RE: Twisted high-rise
many structural engineers are underpaid compared to architects.
RE: Twisted high-rise
Thank you. Very informative article. I would not have guessed concrete construction. I would have guessed steel, some kind of braced frame. I guess that is why we leave that sort of thing to you structural experts. Just seems counter-intuitive.
Good day,
EEJaime
RE: Twisted high-rise
The material used, steel vs. concrete, depends to a large degree on the location around the world. Concrete technology, with high strength concrete, prestressing, etc. has developed to the point that concrete is often competitive with steel for high rise construction.
RE: Twisted high-rise
EEJaime
RE: Twisted high-rise
Mike McCann
MMC Engineering
RE: Twisted high-rise
EEJaime
RE: Twisted high-rise
Probably did have a wind tunnel test, which is common for high rise structures. When wind tunnel testing is done, it often reduces the required wind loading based on prescriptive codes. The mass helps to resist overturning due to wind.
I agree that the structure is a monument to someone's monumental ego (could be the architect or the owner), but with today's computing capabilities, it does not present particularly challenging structural problems.
RE: Twisted high-rise
Good article, but did not mention the torsion on the core due to sloped columns. I think that would be one of the design challenges.
RE: Twisted high-rise
This is one of the few times that I have to disagree with you, respectfully of course. In this case, the architects and SEs had to be working closely to achieve the common goal, just like the Burj Khalifa. I feel as though while architects can be a major pain in the ___, they also get many of us structural engineers to think outside the box while producing some amazing visual structures. While more efficient, cost effective structures would typically be present if the look of the building was dictated by the SE, they certainly may be less desirable aesthetically speaking.
RE: Twisted high-rise
RE: Twisted high-rise
My OP was not at all disparaging of any profession. I was admiring the innovation and the SE's abilities to make such a different and seemingly unlikely structure a success. It has been my privalege to work on a few projects which pushed the envelope of applied engineering in many fields.
I was simply asking you structural experts about the types of connections and was somewhat surprised to find out this was basically a concrete structure. I think it's a great looking building. My schooling is in aerospace engineering and I have always sought the most efficient, elegant solutions to the problem at hand. This design just seems so many miles out of the box that I anticipated some immensely different structural design.
Regards
EEJaime
RE: Twisted high-rise
I don't think anyone was being critical of your OP. Myself especially.
RE: Twisted high-rise
RE: Twisted high-rise
In structural engineering for a new design/concept for a major structure as this, the test is not in the lab, other than wind tunnel or shake tables, and primarily the numbers from our calculations are used to construct the building that is immediately occupied by the public. Therefore, he risk to the public is much greater, in my humble opinion, due to an inherent lack of actual load testing. There are examples of structures that were constructed and failed due to unanticipated loading situations. We cannot always anticipate all the load cases, but when we forget the one causing failure, people can die.
Many will disagree here, but I will assert that new innovative, but inherently risky designs such as this one, should have a different "testing" scenario. I have not answers here, only concerns. One example of this is Galloping Gertie, which tested the limits of the bridge structure as an airfoil. Luckily, no one was killed there. A second example was the lack of redundancy in the Twin Towers that contributed, in part, to the catastrophic failure and the loss of many lives. There are other examples.
We, as structural engineers, just have one hell of a lot of responsibility when you stop and really think about it.
OK. I will get off the soap box now. I have my flack suit on...
Mike McCann
MMC Engineering
RE: Twisted high-rise
RE: Twisted high-rise
RE: Twisted high-rise
Mike McCann
MMC Engineering