detailing inquiry

[mezzoms]

dear engineers,

i inquire about the details shown in the attached file

i want to make a detail for continuous slab with cantilever without making any torsion effect on the supporting beam as the designer did not provide this beam with closed stirrups or side bars for torsion

i provide 3 details in the file

detail 1 : recommended by most of my colleagues as the detailed rft extend from the slab to cantilever and the cantilever slab rft extended to the slab without any rft extension into beam body or depth

details 2 and 3

i do not know what is wrong with them , but all of my collegues do not recommend it as slab or cantilever slab rft extend into the beam body which can change the statical system shown in file to another system from the intended one like the beam carry torsion moment which is not designed to resist

i say however the rft extend into beam body but the other slab rft extend also in the beam with Ld which will receive the tension force from beam to the other slab


please give me your opinion

regards
m.samir

 

[dik]

I'd probably run with detail 2, but would not connect the bot rfg in the cantilever to the top reinf and would extend it into the slab on the right if you need it for compression steel (deflection or whatever), else, I would omit it.

Dik

 

[JAE]

Here's one take on it:

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faq731-376

 

[JAE]

By the way - definitely NOT detail 3

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[KootK]

We addressed a nearly identical problem recently here: Link. There's good, relevant information in that thread and my suggestion from it is shown below. The bottom steel isn't terribly important here. just lap it at the offset as you've shown in your detail #2.

A structural step up onto a balcony is a rare thing (drainage). Now, low and behold, I've encountered it twice in the space of a few weeks. I often get the impression that, somewhere in the world, there are actually groups of people working on the same problem. Or one, very conscientious person with four Eng-Tips accounts, who knows.

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.

 

[dik]

JAE... pretty much same wavelength... good comment on Detail 3.

Dik