## Robot Structural Analysis

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# Re: TANK FOUNDATION

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The values of spring supports were:

Uz= 8000kN/m3*0.1m*0.1=80kn/m were 0.1X0.1m the area of each finite element

Ux=Uy=30%*80=24kN/m

the displacement for DL1 is equal to 30.8cm wich is 100 greater than the expected: 23.4kN/m2 (DL)/8000kN/m3=0.003m=0.3cm, where 23.4kn/m2=7029kN (DL resultant reaction) / 300m2 (area of base of foundation)

I think that the displacement of 30cm refers to 80kN/m3 that I applied as spring of each support.

# Re: TANK FOUNDATION

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You mean every node of finite element on film plate to be connected to the respective node of finite element of plate of foundation? Is there any way to make this easy, because I think that will take for ever!

# Re: TANK FOUNDATION

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You mean every node of finite element on film plate to be connected to the respective node of finite element of plate of foundation?

Yes.

Is there any way to make this easy, because I think that will take for ever!

A few seconds with bars http://screencast.com/t/n5HDenB9mM

some more with rigid links http://screencast.com/t/frMjo8r2ojN

**Rafal Gaweda**

# Re: TANK FOUNDATION

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Hi, I replaced the "film" panel with a panel of 10cm thickness with Kz, Ky,Kx the same to film panel and a material which has the same properties as C30/37 but almost negligible density. The results were fine!!

I finished my foundation but I have some problems with orientation of reinforcement and the bending moments to the small direction of 200cm thick panels.

For the reinforcement of pedestal ( 200cm thk shells) I tried two different things:

- The one was to determinate as main reinforcement a polar one with center the point 0,0,0 (I wanted exactly the opposite, this reinforcement to be the secondary, and the perpedicular the main, but I couldn't find how to do that). Also, the reinforcement type of calculation is "simple bending for this case (the name is 200th polar). I set this parameter to all the shells of the pedestal apart of 9 shells :249 250 253 265 266 269 281 282 285
- The other reinforcement type that was set to the 9 previously mentioned shells, was to set as main vendor the long edge of shell 266, and the reinforcement calculation type to be under bending and tension/compression. To these 9 shells I also used an orthotropic material which I named TH200.2_2. You can check it's properties in robot file that I am attaching.

The two "test" that I describe above was in my attemption to make the pedestal act as "beam". The results when I used a shell of 200cm thick as pedestal with reinforcement under bending + T/C with polar system of main reinforcement were given a greater bending moment along the small dimension of the pedestal and not along the circular perimeter of it (or I think so, because I am not sure if I understand the orientation of bending moments and reiforcement correctly). The pedestal in reality will have the main reinforcement parallel to the perimeter of the pedestal and not perpendicular to it.

What is the right way to have results like the ones that I am expecting to see? is it better if the pedestal (shell 200cm) to be modeled as a beam and to connect it with the shells of 60cm with rigid links? what model method would you propose?

I split the zip file to two parts due to large file

# Re: TANK FOUNDATION

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And one more question, that maybe will solve my problem. At the tables of detailed results of maps for the FE, there is the choise to have the results at the panel/node or in elements centers. Because I have a lot of extremes at the nodes which is a local problem and I think that the solution will not be close to reality, can I design the elements (reinforcement required module) for the results in the elements centers? Can I represend to map of results the ones from the centers of the FE only and not the nodes? When it says " element center" it means the center of the FE or the center of the shell?

# Re: TANK FOUNDATION

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The one was to determinate as main reinforcement a polar one with center the point 0,0,0 (I wanted exactly the opposite, this reinforcement to be the secondary, and the perpedicular the main, but I couldn't find how to do that).

Example: http://forums.autodesk.com/t5/Robot-Structural-Analysis/modeling-a-water-tank-shell/m-p/4726915#M196 ...

**Rafal Gaweda**

# Re: TANK FOUNDATION

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I am not sure if I understand the orientation of bending moments and reiforcement correctly).

http://forums.autodesk.com/t5/Robot-Structural-Ana

lysis/circular-slab-on-springs/m-p/3615446#M7437

**Rafal Gaweda**

# Re: TANK FOUNDATION

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Because I have a lot of extremes at the nodes which is a local problem

That's why I told you to use more connectors (bars or rigid links like on my movies).

can I design the elements (reinforcement required module) for the results in the elements centers?

No.

Can I represend to map of results the ones from the centers of the FE only and not the nodes?

No.

When it says " element center" it means the center of the FE or the center of the shell?

it means the center of the FE

**Rafal Gaweda**