Wind pulsation and problems of modeling

Hello! Tell me, please, what went wrong? I have created a scheme of multi-storey frame. Also I have added wind load and pulsation for it, according to the reference. I was very confused by the results. Elevator shafts and the frame itself are moving in different directions. What did I wrong? File is made in LIRA-SAPR 2013. Yours sincerely, Anton!

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Wind pulsation and problems of modeling
 
#1
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Sep 15, 2014 13:21:47
Hello!
Tell me, please, what went wrong? I have created a scheme of multi-storey frame. Also I have added wind load and pulsation for it, according to the reference. I was very confused by the results. Elevator shafts and the frame itself are moving in different directions. What did I wrong? File is made in LIRA-SAPR 2013.
Yours sincerely, Anton!
 
 
 
#2
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Sep 16, 2014 16:35:54
Elements of the staircase and floor slab do not have common nodes.

Edited: alekstish - Oct 7, 2014 17:11:16
 
 
 
#3
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Sep 17, 2014 16:38:43
Thank you very much for the help. Is it possible during the calculation of pulsation set individual constructions, for which it would not be taken into account? For example, in this project elevator shaft works separate from the frame of the building and does not affect its movement. At the same time, pulsation on this shaft is calculated.
Yours sincerely, Anton
 
 
 
#4
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Sep 18, 2014 07:41:36
If shaft does not affect loads on the basis, then maybe it is easier not to set shaft?
You can define loads from the shaft on the basis from results of particular load cases and set them directly as loads.
Previously, you could set super element for not interesting vibrations. Now I do not know whether it works or not.
 
 
 
#5
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Sep 18, 2014 10:42:51
It is enough to have two load cases for constant load. First is for the shaft, and other is for the rest. Dead weight of the building is taken into account by these conditions.

During the creation of the mass from load cases, it is required to ignore shaft load case. It follows, that connection of two parts of the building during dynamic calculation would be possible only through a common foundation slab and the ground, if you use volumetric elements for modeling. no volume in this case it would be something minor. You can also have a separate foundation for the mine. But in this case it would be something minor. You can also have a individual foundation for the shaft.
 
 
 
#6
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Dec 11, 2014 12:01:17
Hello! Consult me, please, on next question. I set wind load taking into account pulsation (dynamic load case). One of my colleagues said that load in this case, need to be specified only for nodes. Otherwise, the calculation will be performed correctly. For example, the monolithic wall is modelled using elements 0.3x0.3m. The uniformly distributed wind load at the given height is 35 kg/m2. It means that I have to set in each node: 0.3x0.3x35/4=0.79kg. Is it impossible to set uniformly distributed load on the plate? I have not found information about this in the LIRA manuals. Yet :D
 
 
 
#7
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Dec 15, 2014 11:03:13
Hello, Kateryna
Really, there was such a restriction in earlier versions. At the moment this is not necessary. When using large grid of finite element you should pay attention to boundary conditions which can take part of the load.
 
 
 
#8
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Dec 15, 2014 11:55:53
Thank you for the answer. I have managed next in the LIRA references:

How to specify the wind load with pulsation?

In order to analyze the structure for wind load with pulsation, you should specify two load cases. One of them, e.g. load case number N1, is static and will be named as static wind load case for pulsation. In this load case you have to specify only nodal loads corresponding to wind effect in required wind area.
 
 
 
#9
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Dec 15, 2014 11:59:15
This help section is not corrected. We will fix it.
 
 
 
#10
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Dec 15, 2014 12:09:42
Yay! Thanks! :D
 
 
 
#11
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Dec 19, 2014 14:51:47
Good afternoon. What does it mean "Earlier versions"? Which one? I check the problem (multi-tier flyover), which is made by my colleague. Wind is set uniformly distributed on the metal elements. I decided to add "pulsation component". Is it necessary to reset "static" wind to nodes, or program will correctly work out uniformly distributed load and redistribute loads to nodes independently?

I have LIRA-SAPR 2012 (R3.2)
Thank you
 
 
 
#12
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Dec 19, 2014 15:02:51
This seems to be the fifth version of the LIRA and earlier one. I don’t know if there were any restrictions between fifth and eighth version, but eighth version doesn’t have it.
 
 
 
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