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elevated conical tank:seismic and hydrodynamic loads calculation

35 REPLIES 35
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Message 1 of 36
REDO10
2158 Views, 35 Replies

elevated conical tank:seismic and hydrodynamic loads calculation

Hi,
I'm looking for an exemple of modeling seismic and hydrodynamic loads for an elevated conical tank!
I tried modeling it, but when I define masses, the following message appears " load by hydrostatic pressure can not be converted into masses. delete the hydrostatic pressure of the case converted"

I can't attach my file bellow, because it's too large (114 Mo).

thanks.

35 REPLIES 35
Message 2 of 36
Rafal.Gaweda
in reply to: REDO10

"Note For shell structures a hydrostatic pressure load cannot be converted to masses."
http://docs.autodesk.com/RSAPRO/2014/ENU/index.html?url=filesROBOT/GUID-FEC73829-9EDF-406B-9BAB-4A92...


Rafal Gaweda
Message 3 of 36
REDO10
in reply to: Rafal.Gaweda

thanks Rafal for your reply
so how can I define the masses due to liquid?
should I set a master node and assign to it mass of liquid? or how?
if you have an example of modeling it's better
thanks
Message 4 of 36
Rafal.Gaweda
in reply to: REDO10
Message 5 of 36
REDO10
in reply to: REDO10

Hi,

I attach my file below
Can you help me add water masses?
and how I can get the resulting seismic forces at the base for calculation of foundations?

Thanks

Message 6 of 36
REDO10
in reply to: REDO10

No reply!!!! Smiley Indifferent

Message 7 of 36
Rafal.Gaweda
in reply to: REDO10


Can you help me add water masses?

 

Look at post 4 above or calculate nodal masses by your own and apply to nodes.


and how I can get the resulting seismic forces at the base for calculation of foundations?

 

I think, firts you have to create combinations  or generate automatic combinations then look at reactions for them.

 



Rafal Gaweda
Message 8 of 36
REDO10
in reply to: Rafal.Gaweda

thanks Rafal for your reply
1 - Have you seen my model? no comment to do?
2 - for assign masses,  I looked at the post4 but I did not understand the procedure to do so.
can you make a demonstration for me or introduce the masses in my model?
3 -
for the calculation of foundations, should I select the reduced forces for the combination in question?

Thanks.

Message 9 of 36
Rafal.Gaweda
in reply to: REDO10

1 - Have you seen my model? no comment to do?

 

No combinations, 


2 - for assign masses,  I looked at the post4 but I did not understand the procedure to do so.
can you make a demonstration for me or introduce the masses in my model?

 

Example for one (half) strip : http://screencast.com/t/vHD6OhqLWkAd

of course set proper value ; then this load can be converted onto masses.


3 -
for the calculation of foundations, should I select the reduced forces for the combination in question?

 

Maybe sum of reactions instead



Rafal Gaweda
Message 10 of 36
t.sautierr
in reply to: REDO10

Once again, "attaching" the water to the building is wrong I think.
Message 11 of 36
REDO10
in reply to: REDO10

Hi Rafal,

I saw the demo that you did, but I have some questions:
1 -Should I define a new load case to assign water masses (it can be dead or live)?
2 -Should I define a mass coeficient for the new load case in calcul option?
I apply the changes I have indicated above, but I got an error message, see the attached capture
thank you.

Message 12 of 36
REDO10
in reply to: REDO10

no reply yet!! Smiley Sad

why you enter the value "1" along the z axis? ... the value of the automatic load generated is 2.5 KN, but in reality it is variable according to a hyperbolic function!
how to get the theoretical reinforcement of the tank? ..when I run the calculation of reinforcement the following error appears : "the element is not calculated, the direction of reinforcement is incorrect" and Should I select the option analytical or wood & Amer?

thanks

Message 13 of 36
REDO10
in reply to: REDO10

Hi,

I calculated the impulsive force and mass induced by the method of HOUZNER and got the following results:                 Fi (impulsive force) = -4562 KN  and  Mi (impulsive mass ) = 1028 t.

how can I enter these values?

NB: I followed Rafal's demo  and I noticed that the period of oscillation does not change compared to the  statitique case, it means that the mass of water is not taken into consideration! Smiley Frustrated

help me plz!

thx.

Message 14 of 36
Rafal.Gaweda
in reply to: REDO10


1 -Should I define a new load case to assign water masses (it can be dead or live)?

 

As you like.


2 -Should I define a mass coeficient for the new load case in calcul option?

 

If you want to convert loads to masses - yes


I apply the changes I have indicated above, but I got an error message, see the attached capture
thank you.

 

File please.



Rafal Gaweda
Message 15 of 36
Rafal.Gaweda
in reply to: REDO10


why you enter the value "1" along the z axis? ... the value of the automatic load generated is 2.5 KN, but in reality it is variable according to a hyperbolic function!

 

As I mentioned thsi was just example of one strip. Set correct value.


how to get the theoretical reinforcement of the tank? ..when I run the calculation of reinforcement the following error appears : "the element is not calculated, the direction of reinforcement is incorrect" and Should I select the option analytical or wood & Amer?

thanks

 

Set Automatic direction or along Z.



Rafal Gaweda
Message 16 of 36
Rafal.Gaweda
in reply to: REDO10

 

I calculated the impulsive force and mass induced by the method of HOUZNER and got the following results:                 Fi (impulsive force) = -4562 KN  and  Mi (impulsive mass ) = 1028 t.

how can I enter these values?

 

What is that?

 

NB: I followed Rafal's demo  and I noticed that the period of oscillation does not change compared to the  statitique case, it means that the mass of water is not taken into consideration! Smiley Frustrated

 

 

File please.



Rafal Gaweda
Message 17 of 36
REDO10
in reply to: Rafal.Gaweda

Hi Rafal, thx for your reply

@Rafal.Gaweda wrote:

 

I calculated the impulsive force and mass induced by the method of HOUZNER and got the following results:                 Fi (impulsive force) = -4562 KN  and  Mi (impulsive mass ) = 1028 t.

how can I enter these values?

 

What is that?


1- I used Houzner's method to calculate hydrodynamic forces generated when seisme happen and I obtained the results above, I want now assign the mass calculated (Mi=1028t) to my model, so pls do that for me (I attached my file below)

 

2- How to obtain reduces forces at base to calculate foundation (no values in the table),show capture below

and is there an addin for transferring reactions to actions and introduce them in a new model to calculate foundation?

 

If you want, I attached a link for Houzner's methode, it is on french

http://www.4shared.com/get/0mZzq6jJ/calcul_pratique_rservoir_au_si.html?sop=true

Thx

Message 18 of 36
REDO10
in reply to: Rafal.Gaweda




@Rafal.Gaweda wrote:

How to get the theoretical reinforcement of the tank? ..when I run the calculation of reinforcement the following error appears : "the element is not calculated, the direction of reinforcement is incorrect" and Should I select the option analytical or wood & Amer?

thanks

 

Set Automatic direction or along Z.


I set Automatic direction then along Z but I still get the same error message!!??

my file is attached above

Message 19 of 36
Rafal.Gaweda
in reply to: REDO10


 

2- How to obtain reduces forces at base to calculate foundation (no values in the table),show capture below

 

Reduced forces should be calculated only for two-dimensional panels with the shape of a convex quadrilateral. They will not be calculated for the following types of panels.

  • Panels created by means of Extrude and Revolve editing.
  • Three-dimensional panels (curved).
  • Panels that are not quadrilaterals.
  • Concave quadrilateral panels (not convex).
  • Panels with variable thickness.

http://docs.autodesk.com/RSAPRO/2014/ENU/filesROBOT/GUID-003921A4-A845-4E06-808F-BC0CFF8A2FDE.htm

 

Use reactions or sum of reactions

 

and is there an addin for transferring reactions to actions and introduce them in a new model to calculate foundation?

 

@Import of reactions to new model@ in http://forums.autodesk.com/t5/Robot-Structural-Analysis/useful-addins-for-Robot-API/td-p/3899448

 

 

 

 

 



Rafal Gaweda
Message 20 of 36
Rafal.Gaweda
in reply to: REDO10


How to get the theoretical reinforcement of the tank? ..when I run the calculation of reinforcement the following error appears : "the element is not calculated, the direction of reinforcement is incorrect" and Should I select the option analytical or wood & Amer?

thanks

 

Set Automatic direction or along Z.


I set Automatic direction then along Z but I still get the same error message!!??

my file is attached above


This part of model (see below) must be made as a separate panel because angle between Z global axis and its plane is 90deg

 

deckwatertank.jpg



Rafal Gaweda

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