T-beam Design - Slab reinforcements.

[FixitFelix]

I need some help guys, I'm a bit rusty with my concrete design. I am to analyze an existing concrete building with T-beam construction. I am wondering if you guys consider the slab reinforcement as part of your As and/or As'. The building is in a high seismic zone area. I am aware of the ACI strong-column-weak-beam requirement that you need to include the contributions of the slab reinforcements in your beam flexural strengths. Is it just for that requirement or can you use that it in general? Hope you guys can help. TIA.

 

[rapt]

The reinforcement in the slab parallel to the beam and within the effective flange width can be included in the flexural design of the beam.

Only reinforcement within the beam web width can be included in the shear design.

 

[KootK]

My thoughts:

1) Can use As, probably wouldn't use for As' unless well restrained from buckling.

2) Rebar lateral offset from beam web extends bar extension lengths.

3) Watch your splices in the slab rebar.

4) Most of slab rebar won't be useful for transferring moments into columns.


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.

 

[FixitFelix]

Whats the reason for number 4? Is it because the slab bars on the slab would probably not be directly connected to the column?

 

[KootK]

Whats the reason for number 4? Is it because the slab bars on the slab would probably not be directly connected to the column?

Exactly.

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.