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## Robot Structural Analysis

Product Support
Posts: 5,111
Registered: ‎12-17-2010

# Re: Assigning Stories

01-14-2013 01:51 AM in reply to: Tuctas

It removes the assignment of the story from objects that do not 'meet' the geometrical limits of the story they are assigned to.

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

Artur Kosakowski
Distinguished Contributor
Posts: 202
Registered: ‎10-10-2012

# Re: Assigning Stories

01-14-2013 02:23 AM in reply to: Artur.Kosakowski

So if we have checked this box, the elements that do not meet the geometrical limits of a storey are ignored during the calculations of different kind of values of stories (in other respects the calculations are being carried on normally)?

Distinguished Contributor
Posts: 202
Registered: ‎10-10-2012

# Re: Assigning Stories

01-14-2013 02:58 AM in reply to: Artur.Kosakowski

Please add two more questions (in order to clear out how Robot works in these cases).

If we don’t make any manipulation but we define stories with the “normal” way, so these “red” elements will be included in the above storey:

1. In which way does Robot calculate the averaged storey displacements in such case?

I mean that if these “red” elements belong to the above storey, how exactly the “average displacement of the gravity center of the storey slab” is calculated? (help topic: http://docs.autodesk.com/RSA/2013/ENU/index.html?url=filesROBOT/GUID-890C3B44-F7EE-4BB1-8C39-19F445B...).

Are the nodes that belong to those “red” elements being considered in the slab that they physically belong or not?

2. The calculation of  Center of gravity of floor slab (F) of the storey below does it takes into account these “red” elements or not?

Product Support
Posts: 5,111
Registered: ‎12-17-2010

# Re: Assigning Stories

01-14-2013 05:57 AM in reply to: Tuctas

So if we have checked this box, the elements that do not meet the geometrical limits of a storey are ignored during the calculations of different kind of values of stories (in other respects the calculations are being carried on normally)?

Correct. You can also force Robot to calculate them as being assigned to the story below by setting the verification to none (Job Preferences > Structure Analysis) ignoring errors and warnings but then the check of the correctness of the results is entirely in your hands.

Artur Kosakowski
Product Support
Posts: 5,111
Registered: ‎12-17-2010

# Re: Assigning Stories

01-14-2013 06:05 AM in reply to: Tuctas

If we don’t make any manipulation but we define stories with the “normal” way, so these “red” elements will be included in the above storey:

1. In which way does Robot calculate the averaged storey displacements in such case?

I mean that if these “red” elements belong to the above storey, how exactly the “average displacement of the gravity center of the storey slab” is calculated? (help topic: http://docs.autodesk.com/RSA/2013/ENU/index.html?url=filesROBOT/GUID-890C3B44-F7EE-4BB1-8C39-19F445B...

Are the nodes that belong to those “red” elements being considered in the slab that they physically belong or not?

The average displacement of the story is the weighted displacement of the center of the gravity of the ceiling of the story where the weight is the mass of the surface elements of the ceiling therefore it does not depend of the columns from the above or below.

2. The calculation of  Center of gravity of floor slab (F) of the storey below does it takes into account these “red” elements or not?

No, it does not.

Artur Kosakowski
Distinguished Contributor
Posts: 202
Registered: ‎10-10-2012

# Re: Assigning Stories

01-15-2013 01:28 AM in reply to: Artur.Kosakowski

I made an investigation between 3 cases:

1st case, the results came out by leaving the program to define stories “normally” without any manipulation,

2nd case, the results came out by neglecting the “red” elements from any storey (this can be done not by using the options of the window “Assign Geometrically” but through the option “Advanced options” of the window in which we normally define stories),

3rd case, the results came out by assigning manually to the “red” elements the 1st storey.

There are similar results between 2nd and 3rd case (except of course the value of mass at the ceiling of the 1st floor).

Between 1st case and 3rd case there was a difference at the coordinates of the Center of gravity of 2nd (!) storey slab and thus in the average storey displacements (and so the drifts). I cannot explain it..

Between all cases there are differences in the results of modal analysis (periods, relative masses e.t.c)!? (Although, the total mass was equal). Modal analysis should not get bothered by any kind of manipulation about stories..

Product Support
Posts: 5,111
Registered: ‎12-17-2010

# Re: Assigning Stories

01-15-2013 05:08 AM in reply to: Tuctas

Send me these 3 files please.

Artur Kosakowski
Product Support
Posts: 5,111
Registered: ‎12-17-2010

# Re: Assigning Stories

01-17-2013 04:08 AM in reply to: Tuctas

Between 1st case and 3rd case there was a difference at the coordinates of the Center of gravity of 2nd (!) storey slab and thus in the average storey displacements (and so the drifts). I cannot explain it..

I can't see any difference for F.

Artur Kosakowski
Distinguished Contributor
Posts: 202
Registered: ‎10-10-2012

# Re: Assigning Stories

01-17-2013 11:00 AM in reply to: Artur.Kosakowski

It is strange, when i firstly made the investigation the results were different, now that i run again the analysis finally are the same indeed... (see the attached file that came out after the initally conversion of the table with values of stories to excel).

Although, the displacements still remain different and the same thing happens to the results of modal analysis, that it is not normal.

Product Support
Posts: 5,111
Registered: ‎12-17-2010

# Re: Assigning Stories

01-18-2013 12:29 AM in reply to: Tuctas

It is strange, when i firstly made the investigation the results were different, now that i run again the analysis finally are the same indeed... (see the attached file that came out after the initally conversion of the table with values of stories to excel).

I'm sorry but I'm not able to investigate the situation that is impossible to be reproduced.

Although, the displacements still remain different and the same thing happens to the results of modal analysis, that it is not normal.

I will try to check this too but it may take me some time.

Artur Kosakowski