ROBOT VS ETABS why have the DIFFRENCE

[Anonymous]

I set up two models which are etabs and robot. When set both model suport are pinned. the reaction of support is very small different around about 0.01

But when i set support is fixed , the models reaction have a big difference.

why have the  DIFFRENCE ? how can handle it 

please help me 

[Artur.Kosakowski · Accepted solution]

Hi @Anonymous

Perhaps you should start with two columns and a beam on top of them? Do you have any special 'feature' applied to the beam to column connection in ETABS as e.g. rigid-link, additional stiffening etc. ?

[Anonymous]

the latest models

https://drive.google.com/drive/folders/1D_QFpDhTgQdoqc2GXTENgBVtZ6OSfBZp?usp=sharing

[saclovitzky]

Hello,

Pls. see attached. Is that the same way when you exported it to e2k file?

I still cannot open your file?

[Anonymous]

it is that way

[Anonymous]

when the support set to the pinned support after using the same martial ,the result of etabs and robot is very close.

But when the support set to fixed support , the fz will have a large difference. why? 

[Anonymous]

Do you know the etabs wall support and the robot support ?

how to make them the support of wall is same?

[saclovitzky]

Yes that's the only way to convert it to e2k file. If you do that any version can open it. What version are you using?

[Anonymous]

 etabs 2016

[Anonymous]

can you set up a simply more stories sample share to me ? etabs and robot 

i want to see what difference between you and me

[saclovitzky]

Pls. see attached on how to provide linear support on walls for both ETABS & ARSAP.

I would suggest that you  model simple "2D" frames for both ETABS & ARSAP, dont worry about material properties for the moment.

Just model it and play around with it. Do the same modelling steps for both softwares. Until you convinced yourself that,generally, results are closed enough for both softwares(any softwares).

[Anonymous]

how to go to windows to modification the wall support in etabs?

robot wall support only can select  linear pinned support  only can choose node or planar

[saclovitzky]

You can have pin/fixed linear support in ARSAP.

In ETABS, pls. see attached(showing step by step menus).

Also, it is more "appropriate" to go  to this site https://www.csiamerica.com/products/etabs, if you want to know more ETABS.

[saclovitzky]

You interchange the depth and width of rc beam in ETABS(pls. see attached), that's why the difference in reactions  are substantial.

Change it and you're fine

[Anonymous]

thank you very much 

the result is very close 

but the Fy have the different is very small  but in percentage is large  

(0.06-0.04)/0.04=50%

i will set up another model to try 

[Artur.Kosakowski]

Hi @Anonymous

Out of curiosity: why in ETABS for a symmetrical model you have non-symmetrical results?

[Anonymous]

may the center point i not set ?

i know the etabs can set the center point

do you know to set ?

https://www.youtube.com/watch?v=ReQ7IoXGv1U

go to 12:00 

is this ?

but i donot set to the slab

[Artur.Kosakowski]

Hi @Anonymous

I don't know and don't have ETABS but IMHO if you are trying to investigate such small differences you have to make sure your reference model is correct in the first pace. 

[saclovitzky]

Hello,

Results that you have for the 2 softwares are acceptable in practical  sense. If you want them to have similar results to the nth degree is next to impossible.

Designing structures is not only crunching numbers from other softwares. There is more to life than computer output results. Try  to develop your engineering common sense for your own good.

[Anonymous]

the etabs wall support still not like the robot support like a linar

the etabs wall support still  is the 2 support

[Anonymous]

can you answer the qustion  of  saclovizky 

Out of curiosity: why in ETABS for a symmetrical model you have non-symmetrical results?

i have the same question