topic Re: Modeling opening in steel column in Robot Structural Analysis Forum

Modeling opening in steel column

antonio.lafuente — Fri, 08 May 2020 10:50:54 GMT

Hi there!

How could I model the reduced capacity of a steel column (HEA 160) with an opening like the one in the figure below? Thanks in advance for your comments

Cheers

Antonio

Re: Modeling opening in steel column

Rafacascudo — Fri, 08 May 2020 15:02:46 GMT

I never tried , but maybe you can try modelling an equivalent section on the region of the hole using "Special" Section.

Check here https://help.autodesk.com/view/RSAPRO/2020/ENU/?guid=GUID-07F57C8A-E5C6-4A00-A92A-956EA0626D69 to see how equivalent properties are calculated

Or maybe you can create a custom section on "Section definition" module and then go to Ruser`s Section database and edit the section properties to what you need/want

Re: Modeling opening in steel column

antonio.lafuente — Mon, 11 May 2020 14:09:21 GMT

Thanks Rafa

I created a superbar made from two standard HEA160 and a custom special profile. That seems to work but at the steel design phase I get an error saying that the section is not supported by the code. Are there any standards I can use that allow this type of special sections? It should still be compatible with Eurocode 3 since is the standard I have to evaluate the structure to. Thanks in advance

Antonio

Re: Modeling opening in steel column

antonio.lafuente — Mon, 11 May 2020 14:33:54 GMT

Okay, I just read in the link you sent that only do this type of assessment under the Polish code PN90/B03200. I wonder how this compares to Eurocode and/or if I should just have two separate Autodesk Robot files one using the Polish code for this column and the standard one for the rest...

Also in the report I'm getting results for my superbar (#400) and just one of the smaller bars (#70) but not the other two (#66 and #68). Since I checked that components of superbars should not be taken into account I'm not sure why do I still see results for bar #70. Any ideas?

Re: Modeling opening in steel column

Rafacascudo — Mon, 11 May 2020 15:17:02 GMT

In this case that you want the bar to be designed ,maybe you should follow the last sugestion I made on my last message .

" Or maybe you can create a custom section on "Section definition" module and then go to Ruser`s Section database and edit the section properties to what you need/want"

Then ,save it to user´s database with the appropriate section on the dropdown menu, so it can be designed.

Open the section database and edit properties you want .Leave the section line before closing database

Fully Close RSA ,so user´s database can be updated.

Open and load the edited section into your model

Then on the the design module , edited properties will be used.

Re: Modeling opening in steel column

antonio.lafuente — Tue, 12 May 2020 13:52:09 GMT

Hi Rafael

Let me see if I understood. What you are suggesting is to create a super bar made of three chunks, where the middle one is made from a user-defined section with the modified properties corresponding to a section with a hole in the middle? If so, is there a way use robot to calculate the section properties of the section with the hole?

Thanks in advance

Antonio

Re: Modeling opening in steel column

Rafacascudo — Tue, 12 May 2020 14:58:37 GMT

Ax ,Ay,Az, Iy and Iz are easy to calculate. Just suppress the web area contribution caused by the hole presence.

For Ix , you can try creating the section on section definition module ,and see what it gives for IX.

Or you can use that equivalent compound section to check all these properties

Re: Modeling opening in steel column

antonio.lafuente — Tue, 12 May 2020 15:09:50 GMT

Thanks again. How would you check these properties in the original compound section? Would you please mind guiding me a bit?

Re: Modeling opening in steel column

Rafacascudo — Tue, 12 May 2020 19:05:17 GMT

just check the equivalent compound section on the properties table

Re: Modeling opening in steel column

antonio.lafuente — Thu, 14 May 2020 13:44:30 GMT

HI Rafa

I'm not sure that will work. I have here a toy problem with four possible definitions and can't see any difference in the results. I have attached the file in case you can have a look. What do you think?

Then I don't see how to modify Wply and Wplz. And finally the section area properties don't seem to match those used in the member evaluation

Cheers

Antonio

Re: Modeling opening in steel column

Rafacascudo — Thu, 14 May 2020 17:57:52 GMT

Antonio ,

I am not familiar with Eurocode , but ,

1- Yes Ay and Az are different on the section design module compared to the values on properties tables and databases. This happens to all databases. I don´t know if it is code related.

2-Wply and Wplz are available on the database columms MSY and MSZ and correspond to the values used on design module.

3- One difference I noticed is that Your modified section has S275 as material while all the others on your model have Stainless steel 304L

Sorry to be not more useful. Maybe someone more familiar with Eurocode can help you better.

Did you try manual calculation for this example?

Re: Modeling opening in steel column

antonio.lafuente — Fri, 15 May 2020 09:54:13 GMT

HI again

Could you do the analysis of this column out of panels? And if so how would this be done?

Re: Modeling opening in steel column

Rafacascudo — Fri, 15 May 2020 14:38:51 GMT

Yes , something like below.

But design would have to be done manually

Re: Modeling opening in steel column

antonio.lafuente — Mon, 18 May 2020 11:24:47 GMT

Interesting... I had never seen this in Robot. Are there any webminars where this is described? I wouldn't know where to start... Thanks in advance

Antonio

Re: Modeling opening in steel column

Rafacascudo — Mon, 18 May 2020 17:38:50 GMT

Just model the bar as a group of panels ( Search for and addin made by @Rafal.Gaweda that transforms a bar section on FE panels ) and then , connect this FE bar to the bar end nodes using rigid links as I shown above.

Re: Modeling opening in steel column

Rafal.Gaweda — Tue, 19 May 2020 05:57:57 GMT

Hi @antonio.lafuente

Here You are:

https://forums.autodesk.com/t5/robot-structural-analysis-forum/api-macro-for-creating-panel-profiles-from-bars/td-p/6045239