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I need help regarding beam supported composite slab.

I need help regarding beam supported composite slab.

I need help regarding beam supported composite slab.

(OP)
According AISC manual 14th edition it is not recommended to use Y2>7. So AISC recommendation not to use more than W16x45 for the depth of 16'' beam & there is no value given for size more than W16x45 in table 3-19. But RISA floor and Enercalc is giving sizes more than W16X45. For Architect requirement I can not use beam size more than 16". So Which recommendation should I use and why?

Thanks

RE: I need help regarding beam supported composite slab.

Can you point to where AISC requires the flange width to be less than 7". What AISC section?

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RE: I need help regarding beam supported composite slab.

(OP)
If you go to page 3-12 in AISC manual 14th edition you will find that it discouraged to use PNA location more than 7.

RE: I need help regarding beam supported composite slab.

Debashis Das,

The location "7" is the point where ΣQn = 0.25FyAs. This is a very low PNA position and represents a composite beam with 25% composite behavior which has historically been the lower bound limit of composite shapes.
In other words, below 25% you are not adequately engaging the concrete - you would get substantial slip between the steel and concrete and this could significantly affect your overall stiffness of the slab-beam.

Read the commentary in the AISC specification (section I3.2 - page 16.1-355 and through 356). They outline some of the concerns of using lower composite action.
Hope this helps!

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RE: I need help regarding beam supported composite slab.

...and to further answer your real question - I think the AISC table only goes to W16x45 to limit the size of the table (and the whole book) in that a heavier W16 would not typically be economical compared with a deeper shape.

If you are limited to 16" then heavier W16's could be used. The table nor the spec prohibits that from what I can see.

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