Story weight

[medo]

How to calculate story weight of a building without dividing vertical structural members in half?
For example, on a 3 story structure, the first story is defined with all structural members from H1/2 to H2/2, the second from H2/2 to H3/2 and the third from H3/2 to H3.

[Gazes]

All results for stories should be calculated properly without having to divide columns. The only thing is that such long column has to be "connected" with each story level it goes through (e.g. by placing a node on it on each story level - one can use Edit/Divide option for this with option "Generate nodes without bar/edge division" checked).
(Usually columns are automatically connected with storeys via mesh nodes)

[medo]

To be more specific, please look at the attached figures.
Figure 1 is displaying story definition without dividing columns in half.
Figure 2 is displaying story definition with dividing columns in half.

I need to have story definition as in Figure 2, but without dividing columns or vertical panels. If I don't divide the columns than they will be not included in the story.

[Mel_S]

There is a node where columns are connected with the slab. Create a temporary supports to these nodes and find the reactions. Same thing with the upper story. If you divide these two reactions you have the weight of a story.

[waldemar.okapa]

Do not divide the columns.
Just put nodes on columns at the story levels. (Edition > Division... by plane)

Column bars will be divided into finite elements which are assigned to storey by levels.
See the screencapture.

[waldemar.okapa]

column 105 is one bar, divided into FE at storey level:

[medo]

Thank you Waldemar. And what about vertical panels?

[Gazes]

Put lines/polylines on vertical panels at the story levels.

[medo]

Do not divide the columns.
Just put nodes on columns at the story levels. (Edition > Division... by plane)

Column bars will be divided into finite elements which are assigned to storey by levels.
See the screencapture.

I did that, but no help. I used the option Edit>Divide>by a plane I used Z axis and generated nodes without bar/edge division on each half story level (center of columns on each level). This just generated nodes and when I defined stories, again I got what I don't want.
Am I doing something wrong?

[Gazes]

Run calculations.

[medo]

Run calculations.

Nope. The columns are still outside stories.
If any help, I am using Robot Millennium ver. 20.1. I tried this on ARSA 2010, it works. Am I missing some setting when generating finite element mesh?

[medo]

Ok, now it worked. I don't know what happened, maybe the program needed restarting.
Only one more thing. Why vertical panels are not colored like horizontal ones that belong to a story? I see some gray colors for the FEs, and appropriate color for the lines defining the FEs. Does it mean that everything is Ok now?

[Gazes]

It looks OK now.
Your vertical panels don't belong to a story (that's because their bottom is on the different story than top) and they aren't filled with story color but remain gray. Finite elements of these vertical panels are correctly assigned to stories and only their edges are visualized with story color.

[medo]

Great. I am on a good way now :)

When calculating story weight, the program calculates only self-weight of the structural members. Why it does not include the weight of additional 'dead' load or 'live load' in the Story Table Results from other load cases?
Instead, for each load case in results table, the program displays the same values as for self-weight.
I need to have total weight of one story with all load cases included.

[smm.144]

medo, what would you do with nonstructural walls mass?

[smm.144]

When calculating story weight, the program calculates only self-weight of the structural members. Why it does not include the weight of additional 'dead' load or 'live load' in the Story Table Results from other load cases?
Instead, for each load case in results table, the program displays the same values as for self-weight.
I need to have total weight of one story with all load cases included.

Did you tried analysis>analysis type>load to mass conversion?

[medo]

Did you tried analysis>analysis type>load to mass conversion?

Yes I did that, but nothing is changed. Look at the attached figure. Load 1 is self-weight, Load 2 is dead load=6 kN/m2, load 3 is live load=3.50 kN/m2 and 2.0 kN/m2 on roof level.

[smm.144]

Yes I did that, but nothing is changed. Look at the attached figure. Load 1 is self-weight, Load 2 is dead load=6 kN/m2, load 3 is live load=3.50 kN/m2 and 2.0 kN/m2 on roof level.

What is the story area?

[pascal.bogdan]

Hey, I think the fastest solution is to upload the structural model file here and we can look and give you a more accurate answer.

[medo]

This is the example file.

[smm.144]

Hey, I think the fastest solution is to upload the structural model file here and we can look and give you a more accurate answer.

Did anybody find any problem in that file?(previous post)

[waldemar.okapa]

Everything is fine, at least on version 2010.

1. Load to mass conversion applies to dynamic analysis only. You will not see any change of storey mass for static cases.
2. In the attached example you have defined modal analysis (case 4) and there you can see the different mass.
3. In the modal modal analysis you have checked 'Disregard density', which means that the model mass is neglected for modal analysis but the converted masses from load are applied only.
Compare sum of reaction for converted cases 2+0.5*3 with the total mass of the building:
1164.92+0.5*637.93=1483.89 (t) It's is OK.

[smm.144]

Everything is fine, at least on version 2010.

1. Load to mass conversion applies to dynamic analysis only. You will not see any change of storey mass for static cases.
2. In the attached example you have defined modal analysis (case 4) and there you can see the different mass.
3. In the modal modal analysis you have checked 'Disregard density', which means that the model mass is neglected for modal analysis but the converted masses from load are applied only.
Compare sum of reaction for converted cases 2+0.5*3 with the total mass of the building:
1164.92+0.5*637.93=1483.89 (t) It's is OK.

I did not exactly get how robot calculates story masses. I changed load to mass conversion settings but the mass of stories did not change. I only want to perform static analysis. How can I get real mass of stories calculated from loads? That means I have to add a modal analysis?