Rectangular Footing Band Reinforcing

[SteelPE]

I have a question in regards to band reinforcing in rectangular footings:

Say I have a footing that is 10 long x 5’ wide x 1’-6” thick with minimal load (say 20k axial). In this footing minimum reinforcing steel will govern meaning we will need to have 3.888 in^2 of reinforcing steel in the transverse direction with 2/3 of this reinforcing located in the band width. While I understand the reasoning for band width reinforcing, does the temperature reinforcing need to be included in the band width calculation?

I have always included the minimum reinforcing in the band width reinforcing calculation, but I'm not sure if this is correct or not.

 

[KootK]

While I understand the reasoning for band width reinforcing, does the temperature reinforcing need to be included in the band width calculation?

I vote no. As you know, the intent of the banding provision is to have lateral rebar disposition reflective of moment distribution. In fact, one could argue that not-banding the t&s reinforcement is the more sensible approach because there will be nothing banded about the temperature and shrinkage reinforcement.

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.

 

[SteelPE]

KootK, I agree for exactly the reasons you point out.

The footings I am having trouble with are long footings with two columns on them. The ones you use to resist the overturning forces of the bracing system. These footings tend to be thick and require a large amount of transverse T$S steel.

 

[KootK]

As an aside, through numerous other threads here, I think that we've established that T&S requirements don't strictly apply to footings. So you might have some other options if desired. Certainly, over 5', it's hard to imagine that T&S stresses would amount to much, even with significant soil drag.

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.

 

[SteelPE]

Never really read through the threads that much. I know the footing section of ACI specifically references. I know we have used a minimum 0.0018xgross area for a long time. Every chart I have uses this minimum as well.

In my instance, combined footings, I fall under 15.10 which specifically references 7.12.2 (with section 7.12 being Shrinkage and temperature reinforcing) so I still need to comply with these requirements..... although, that is not the problem I initially started with above.