Analytical model for stair in order to analyse in robot structural analysis

[muhimdegil]

Hello! I'm trying to get analytical model of stair in revit 2014 in order to analyse my project in robot 2014. But I couldn't. And I modeled floors and slope floor such as stair. But analytical node and lines of floor and slope floor aren't connected. How can I succeed? Isn't there analytical model for stair in Revit 2014. Even I modeled structural stair from existing architectural stair, there still isn't anaylitical modeling option. Help me please! I can't find any answer on the internet.

[AJA14]

Hi. Stairs are architectural elements as far as revit is concerned and have no analytical geometry, only physical. Model your stair as structural floors.

Regards,

[muhimdegil]

Hello! Thank you for reply sir AJA14. But there is still problem. When I modeled structural floor from "Model in place" tool as a stair, there is no option for analytical model. In other word even my stair becomes structural model it is not analytical so that I can't send it to the Robot Structural Analysis 2014 programm. I also used sloped floor and normal floor (structural) which represent a stair. Just maybe structures of sloped floor and normal floors could be similar to the structure of stair.  But analytical nodes and lines of normal floor and sloped floor aren't connected each other. If I use sloped beam then the structure of stair will be completely different. I hope you will give me a comprehensive answer. That will be a very helpful for my project. Thank you.

[thommynator]

u can only model the stair landings, calculate the weight and load of the stair run and place a line load at the stair landings.

[SerhanB]

Hi muhimdegil, I found it as a time saver to analytically model stairs as sloped floors and assign pertinent area loads to them rather than calculating and creating line loads on edges. BUT thats valid only if your analytic stair is 100% in compliance with your 3D model. Slight differences between analytic and 3D model such as difference in slope and length will cause your model to get out of line. You'll end up with a stair with nodes and floor edges aren't connected and once the geometry isn't accurate they will never connect. I advise you to model a sloped floor with precisely correct sketch and height offsets. You may try to introduce an additional 0.1mm margin for offsets in your 3D model, I found it to work with success while aligning analytic floor. Once aligned you can revert back that 0.1mm In revit analytically modelling sloped floors for stairs ramps or roofs takes considerable effort, and sometimes you won't be able to do what you really want. Especially it's still practically not possible to model an analytic spiral ramp 😞

[muhimdegil]

Hello sir! Thank you very much for your concern. And I'm sorry for being so late in thanking you. I've just read your mail now. Since I tried several ways and couldn't succeed, I gave it up. Generally in my country we use russian calculation software Lira 9.6 or SAP for analysing. Also russian code (SNIP). I tried to convert Euro Norm codes to Russian codes in order to use Robot And Revit. But I even couldn't handle RSA itlsef. So I decided to delay it and started some another researches. I didn't check this email for a long time. Now I'm planning to continue that work. I hope you will share your knowledge with me and help about it. Also hope that RSA and Revit2015 has new features such as analytical stair which wasn't in previous versions. 

Lastly I have a personal question for you if don't mind. Are you Turkish? If so I prefer to communicate with you in both languages. Cause my Turkish is better than my English.

Sincerely.. 

[Max.Kotsar]

Hi, muhimdegil!

I use sloped structural floors for stairs modeling. As you can see in this case analytical model is correct. 

P.S. RSA has last Russian codes (SP and SNiP). 

[Joe.Charpentier]

Max, that model looks great!

If anyone else is trying to do this, you have to remember to slope the floor using a slope arrow (within the sketch) in order to get a sloped  analytical model.

If you slope the floor using shape editing tools, you will get a flat analytical model.

The easiest way to do this is to set the head and tail of the slope arrow at the edge of the slab, and set the appropriate elevations.

Joe

[muhimdegil]

            Hi Max! Thank you very much. It was a quite helpful. I've almost done my modeling. But now I'm having problem with loads. I'm trying to define my load cases such as I did in LiRA 9.6 (russian analyisis software) before. I set the russian codes and other option. In LIRA software, first I define my load cases and then parameters of seismic loads are set. Also there is additional option that creates dynamic loads from static ones. For example: Let's say my 1st load case is dead load, 2nd one is live, 3rd one is seismic (X direction) and 4th one is also seismic (Y direction). In "Create dynamic load cases from static one" window there are 3 boxes: 1-dynamic load case number, 2-No.of corresponding static load case, 3-Conversion factor. In other word I create dynamic load case from static load cases (1st case*0.9; 2nd case*0.8, 3rd case*0.5 ) for seismic load X direction and same goes for Y direction seismic load. There is Load to mass conversion window in RSA but no textbox for dynamic load. Also I can't change my analysis type of seismic load case which is created such as other load cases DL, LL etc.. directly to seismic. It requires me to create new case definition in Analysis window in order to use Russian code. I hope you can help me with these issues. And sorry for bad grammar. 

thank you.

[okapawal]

Sorry, in which program or add-in have you got this option "Create dynamic load cases from static one" ?

[Max.Kotsar]

Hi, Pawel!

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okapawal написано:

Sorry, in which program or add-in have you got this option "Create dynamic load cases from static one" ?

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I think, muhimdegil mean Lira 9.6  

[aliyuaziz]

Muhimdegil,

You can find tutorial on running a siesmic analysis here http://docs.autodesk.com/RSAPRO/2014/ENU/index.html?url=filesROBOT/GUID-8D0795BB-F68C-42A6-BE70-A1F7...

I trust this is helpful.

Best regards,

Aliyu A. Aziz

[e0325297]

Hi @Max.Kotsar,

I have tried modelling the stairs the same way you did. However, upon running analysis, every node was instable. I tried solving the problem by adding columns and fixed supports at the base of the columns. However, it didn't help. May I know how do I solve this issue? Please see screenshot of the model for reference. 

[SerhanB]

İf there are instability errors at every node may be you should check if your materials and panel sections are defined and assigned correctly.

[e0325297]

Hi @SerhanB,

Thank you very much for your suggestion.

However, I still have some difficulty. I'm not sure what properties I should change to in order to define the material and panel correctly. Please see this hyperlink for the robot file.

[marcoymleung]

Modelling using sloped and normal floors is correct.  Instability is due to missing bracing between pointed joints, unless you made them fixed joints.