Concrete slab in two levels - design/modeling?
Concrete slab in two levels - design/modeling?
(OP)
How do you guys design concrete slab like this? How to model it? What about reinforcement?
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Concrete slab in two levels - design/modeling?
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Concrete slab in two levels - design/modeling?Concrete slab in two levels - design/modeling?(OP)
How do you guys design concrete slab like this? How to model it? What about reinforcement?
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RE: Concrete slab in two levels - design/modeling?
the step and detail the step "connection" so that moment can transfer though.
The step width (your is 20cm) should be at least twice the step height (30cm), in other words the step width should be 60cm.
Also take note the a step like this will create a slight increase in the deflection, just keep that in mind.
RE: Concrete slab in two levels - design/modeling?
'detail the step "connection" so that moment can transfer through'
any suggestion?
Im confused - because of the geometry of the slab the load will transfer only in short direction (perpendicular to the step)... so the step (beam) actually dont help with bearing the plate. But it has to transfer moments (perpendicular to it) to the lower slab. Right?
It also bothers me becuase the step is near a support (concrete wall).
RE: Concrete slab in two levels - design/modeling?
http://www.eng-tips.com/viewthread.cfm?qid=408814
RE: Concrete slab in two levels - design/modeling?
That changes things drastically.
If the step is in the middle of a span, then I agree - moments, shear forces and deflections are very similar. But not in my case when step is near support:
DEFLECTION:
MOMENTS, SHEAR and AXIAL FROCES:
Looks like step near support has good effect on deflection and lowering moments, but axial forces are huge.
RE: Concrete slab in two levels - design/modeling?
I've always seen this as twice the thicker slab depth (upper/lower). So 40 cm my way. Which is not to say that there's anything wrong with Steyn's method.
The thread that Steyn linked for you has a strut and tie model of the situation that can guide your detailing. If that's insufficient for you needs, let us know and we can provide more detail.
Exactly right.
It's the same problem in my book. Just less moment and less impact on deflection which is nice.
This is because you've pinned both ends of the slab against lateral translation. Are you sure that's appropriate in your case? I would think not based on your sketch. There's almost some unintended source of restraint but that is rarely considered by designers in these situations.
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: Concrete slab in two levels - design/modeling?
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RE: Concrete slab in two levels - design/modeling?
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RE: Concrete slab in two levels - design/modeling?
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RE: Concrete slab in two levels - design/modeling?
RE: Concrete slab in two levels - design/modeling?
RE: Concrete slab in two levels - design/modeling?
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: Concrete slab in two levels - design/modeling?
RE: Concrete slab in two levels - design/modeling?
Generally, I'd model the step as pinned top and bottom and detail for some unavoidable moment transfer. I might also just treat the vertical bit as a support for the higher slab and a load on the lower slab. Sometimes I feel that it's justified to consider multiple load cases to try and bracket the problem.
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.