Autodesk Robot Structural Analysis

[#1]

Dear Colleagues

Could I get responses for the following Inquiries :

•  Why does the max. slab deflection value in the capture (01) is greater than in the capture (02) for the same slab parameters?

• Which deflection value shall I consider as " Long term deflection "?

• Is there any possibility to get the elastic slab deflection directly from ROBOT       ?

Note : If you use any capture for explanation . Kindly , send it as attached .

Thanks in advance.

Refaat

[#2]

•  Why does the max. slab deflection value in the capture (01) is greater than in the capture (02) for the same slab parameters?

I assume that in the first scenario you calculated the deflection for all of SLS combinations (case 40 being the compound case with many components) whereas for the second one only for a single selected one (apparently not the one that gives max. value of deflection).

• Which deflection value shall I consider as " Long term deflection "?

Which design code is concerned? 

• Is there any possibility to get the elastic slab deflection directly from ROBOT       ?

 If you mean uncracked then check the results of the static analysis instead.

[#3]

Dear Artur

Thanks for response , but may I clarify the followings :

- Do you mean that ROBOT in capture (01) doesn't calculate the deflection for the case (40) ? It means that I Can not specify  a case to calculate the long term deflection without running the " deflection verification " ?

- " ACI318-80M" is concerned for long term deflection calculation .

-  Elastic deflection  , I meant " Short term deflection  " for slab . if  possible to get in ROBOT . Kindly , send me a capture for explanation.

Thanks

Refaat

[#4]

- Do you mean that ROBOT in capture (01) doesn't calculate the deflection for the case (40) ? It means that I Can not specify  a case to calculate the long term deflection without running the " deflection verification " ?

If you have a case that include more than one component (e.g. SLS code combinations) and you use it for calculations of deflection than the result is sort of 'envelope' of deflections. On your screen captures you used case 40 for calculations of deflection and 37 for its verification. Mind that for the simplified approach it is important that you divide your slab into panels with 'clearly' defined boundary conditions (line of supports) as it based on the scaling off results from the static analysis. The description of the method is available in Help.

- " ACI318-80M" is concerned for long term deflection calculation .

For ACI displayed values of deflections are the total long-term ones. See the attached picture.

-  Elastic deflection  , I meant " Short term deflection  " for slab . if  possible to get in ROBOT .

No, these values are not available for display.

---

[#5 · Accepted solution]

Dear Artur

Thanks , well done

Refaat