modelling reinforced concrete chimney

[nfarzad]

Dear users
i'm working on RC chimneys. could seismo-struct model the concrete chimney and run adaptive pushover analysis?
regards.

[huffte]

I see no reason why that should not be possible nfarzad.

[nfarzad]

thank you for paying attention to this topic.
could you please tell me how can i get the nodes to the program and assign the elements?
and if it possible could you please tell me which kind of element i can use for the shell to response inelastic?

[huffte]

Hi nfarzad.

Well, I believe you would be best served by downloading the program, going through the Verification Examples, Perusing the Help system and the user's manual.

You are the one who knows how you wish to model the behavior of your chimney and you are the one who can best judge if the element types available in SeismoStruct are appropriate for your structure.

And you can create various models in a matter of seconds using the Wizard feature in SeismoStruct to observe how nodes and elements are defined.

Happy modeling nfarzad.

[seismosoft]

Dear nfarzad,

In addition to the recourses that Tim mentioned, you can find useful information on how to start by viewing the video tutorials on Seismosoft's Youtube channel on:

https://www.youtube.com/results?search_query=seismosoft

Seismosoft Support

[nfarzad]

Dear all
As you mentioned before i watched some movies and read some manuals for modeling my chimney. i used rcchs sections,infrmFB element classes,and for the element connectivity i used center points of 2 rings afret each other,fixed the base,but no other constraints.
i got 0.24 sec as a result in sap2000 for the eiegnvalue analysis but i've got 0.17 here. what is wrong in here.and i should mention that no one of the Gravity and mass window in project setting makes any differences.
regards.

[huffte]

Are your SAP2000 and SeismoStruct models identical with regard to geometry and constraints/restraints?

It appears that the SAP2000 model is more flexible or has more mass somewhere. Does SAP2000 incorporate shear deformations into the elements used for that program?

Is the only mass that due to the elements themselves in both models?

Does one model have a finer element size (more discretization) compared to the other?

Try out these ideas and if none of this gives you a suitable answer, keep asking yourself what could have caused SAP2000 to be either (a) more flexible or (b) more massive.

Best of luck, nfarzad.

[nfarzad]

Dear huffte
i mentioned sap2000 as an example,i did this model in both sap2000 and abaqus 6.10. the answers were 0.24 and 0.23 respectively but in seismo it's 0.17. this is what i can't understand. maybe there is a mistake in my model or mass sources. what do you think how could i check it. and i used mass from materials and not the mass element types.

[huffte]

Well, you'll have to ensure identical mass and stiffness as previously mentioned. The easiest way to be certain you know the mass being used is to lump masses in both models and zero out masses derived from material densities. This would minimize any differences between 'consistent' mass versus 'lumped' mass formulations. And do not rule out the possibility that the mass is fine and it is a stiffness difference between the models. Geometry and material properties must be checked in great detail.