Questions About ACI Code,AISC,and others

[ahmadramadan]

Hi guys
Hope everyone is good

I have couple of questions in my mind(,and I wish if any can help

1.ACI code allow for moment distribution up to 20%,thus Should I consider the new moment distribution in the deflection calculation???
2. Generally speaking point of inflection(zero moment) for the following cases are like the following

a. two end continuous 0.25,0.75 ln
b. one end continuous 0.6 ln

Is it right

3. Regarding frame action, I found command in Safe for rigid zone above columns moment, hence this command will change moment values,and this due frame action,so could anyone explain this)

4.in the AISC 2005 OR 2010 , I am trying to calculate values for shear capacity for HSS rectangular,but cant find special statement to find out values for Cv and Kv ,any guidness

5. Finally, how can i get the distributed load value if I have the moment taken fro the Etabs or SAFE

 

[MacGruber22]

I can answer 1 and 4.

1. I believe you are talking about moment redistribution. If that is the case, serviceability deflection doesn't matter at strength limit states.
4. Page 16.1-71 G5. for Kv. and page 1-95 table 1-12A for Cv unless you need to calculate per page 16-68 G2-3, 4, & 5

"It is imperative Cunth doesn't get his hands on those codes."

 

[ahmadramadan]

Thank you MacGruber22
Regarding Point 1, I don't agree with you, if you make moment redistribution this will affect the section(different cracks to achieve the new moment distribution,which should affect the deflection)
Regarding point 4 ,page 1-95?? all pages has this format 16.1-page number(cant find it)

 

[MacGruber22]

Ahmad,

Why did you ask question #1 if you already were set on an answer? It does affect deflections, but moment redistribution occurs at strength limit states. Unless there is an unusual reason to be concerned about deflections, why would you calculating deflections after plastification of adjacent sections? You no longer have a service load applied at that point in time, so I do not understand.

"It is imperative Cunth doesn't get his hands on those codes."

 

[ahmadramadan]

i got your point

thank you

 

[KootK]

I'll try a couple:

3. Regarding frame action, I found command in Safe for rigid zone above columns moment, hence this command will change moment values,and this due frame action,so could anyone explain this)

When SAFE does its voodoo, it sees the columns a line elements and allows the slab to deform flexurally around the tops of those line elements. In reality, of course, the slab won't be able to deflect much in these ares because of the presence of the columns with finite cross sectional dimensions. When you direct SAFE to model the joints as rigid zones, you are telling the software to account for this in a fashion. I typically use this option when I use SAFE.

5. Finally, how can i get the distributed load value if I have the moment taken fro the Etabs or SAFE

.

I'll assuming that you're speaking of the redistributed load values. If you've run an elastic analysis, then you can't get these out of SAFE (at least not that I know of). You would have to extract the elastic moment values and fiddle with them by hand. I you've run an iterative, inelastic analysis then the program has already done some redistribution for you and I wouldn't mess with it any further.



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.

 

[ahmadramadan]

Thank you Kootk