Deep Beam Maximum Height criteria.
Deep Beam Maximum Height criteria.
(OP)
Hello Everyone!
I am working on a 31 story building and my boss insists to use deep beams as solution for the transition from walls to columns (it is a common practice in the office) but not for a 105 meters high rise.
today I am trying to prove his theory configuring a deep beam with 8.4 meters span and the program I usually use says to me that 10 meters height maximum.
As I understand the height of a deep beam may be relative to it´s span, and it has different behaviors when the relation Height/Span is in low ranges of 0.5 to 1 and an other when that ratio increases from 1.5 to 2.
I can preform a manual revision using struts and ties method, but I will have to design more then 10 different options by hand.
Please if you have any suggestions to my situation, will be appreciated.
Regards
I am working on a 31 story building and my boss insists to use deep beams as solution for the transition from walls to columns (it is a common practice in the office) but not for a 105 meters high rise.
today I am trying to prove his theory configuring a deep beam with 8.4 meters span and the program I usually use says to me that 10 meters height maximum.
As I understand the height of a deep beam may be relative to it´s span, and it has different behaviors when the relation Height/Span is in low ranges of 0.5 to 1 and an other when that ratio increases from 1.5 to 2.
I can preform a manual revision using struts and ties method, but I will have to design more then 10 different options by hand.
Please if you have any suggestions to my situation, will be appreciated.
Regards
MSc. Eng. Serguei Joa
Structural Engineer
Bouygues Batiment International, Cuba.






RE: Deep Beam Maximum Height criteria.
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RE: Deep Beam Maximum Height criteria.
In reality, I'd think construction phasing would eliminate any deep beam concerns over the first pour. I would design the first pour of concrete as the beam and design anything above that as a wall. I'd be way more concerned with the "soft story" that is being created and the detailing of the column to wall reinforcement.
RE: Deep Beam Maximum Height criteria.
You mean where the beam IS the wall for a certain height, right? If so, the bottle neck usually is not so much the wall but:
a) the joint between the wall and the column and;
b) the joint between the wall and the slab if substantial shear will be transferred.
For both purposes, it can be handy to have a conventional, probably not deep beam at the transition.
At those proportions, it's almost certainly a strut and tie thing. Why so many options?
You can find that here if you're interested: Link
This was an excellent thread on a similar topic that may interest you: Link
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Deep Beam Maximum Height criteria.
JAE: Yes, Reinforced Concrete Deep Beams.
Teguci: Thank you for your suggestion, but My model gives back that the higher the deep beam better it can handle the efforts (2000kN/m Dead + 450kN/m Live)
Regards.
MSc. Eng. Serguei Joa
Structural Engineer
Bouygues Batiment International, Cuba.
RE: Deep Beam Maximum Height criteria.
RE: Deep Beam Maximum Height criteria.
Thank you for your suggestions,
Let me clear myself a little:
This is the view of my issue.
The options are due to the different span lengths and continuous changes in architecture that I have to face, usually I do a couple of hand solutions and check similar using software tools.
The article Is great I had a similar info from a book called "Reinforced Concrete Deep Beams" http://files.engineering.com/getfile.aspx?folder=c...
If you got any automation suggestion for this design purpose, I will be very grateful.
Best Regards.
MSc. Eng. Serguei Joa
Structural Engineer
Bouygues Batiment International, Cuba.
RE: Deep Beam Maximum Height criteria.
For gravity load considerations, my automation suggestion would be not to automate. An elastic computer model isn't going to be particularly helpful where you're dealing with strut and tie proportions and a non-linear, cracked material. Research suggests strut and tie models like those presented in the other thread that I linked are appropriate. Under concentric load, that will effectively make your "beam" depth about L/2.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Deep Beam Maximum Height criteria.
Even calculating the column loads using FEM will not be accurate as it does not account for construction sequence and normally leads to an un-conservative result (possibly not so much for deep beams as for flexural transfer beams).
RE: Deep Beam Maximum Height criteria.
Regards,
MSc. Eng. Serguei Joa
Structural Engineer
Bouygues Batiment International, Cuba.