modeling brbf and pushover

[kaspianIV]

hello dear friends
please help me!!!!
I want to modeling buckling restrained braced frame (brbf) and pushover it but i don't know how to do it!!
the basic idea for modeling brb is using truss element for it but it not work! please help me how to do it
also for pushover analysis : do i need for this analysis ,defining all hinges ?

[kaspianIV]

please help!!

[nmb]

In my case, I failed push over analysis using beam element and truss element together in domain "model BasicBuilder -ndm 2 -ndf 3",
because I missed to restrain rotational degree of freedom Rz of nodes of truss elements which should have SP_Constraint Ux and Uy.
The analysis could be succeeded just adding Rz restraint to the nodes.

[kaspianIV]

thank you nmb for your answer
but does anyone have an example on modeling Diagonal braced frame?

I got a model 6 story frame with Diagonal braced according to this example : http://opensees.berkeley.edu/wiki/index ... trated.tcl
to pushover them but periods of its is not correct and unusal http://www.xum.ir/image/FxOR
and also in pushover analysis this error is shown : http://www.xum.ir/image/FxOL
please help me about this problems
Thank you in advance

[arebrahimi]

You can simply use corotTruss or forceBeamColumn element with steel02 material, However you should justify this material before implement it to your model. As i remember Silvia wrote a very useful script for incremental cyclic static analysis, you can find it in the forum. good luck.

[hadikeshtgar]

Hi every body
how i can model BRB with corotTruss or forceBeamColumn element with steel02 material , infact i ask explain me how define nodes and plastic hinges in just BRB element....
please help...
thank you

[saharnaz]

hi.
you can use truss element with nonlinear material for yeilding portion and use elastic beam column element for nonyeilding portion.

[hadikeshtgar]

thank you saharnaz for answer
i use truss element but when i use it in a 6 story frame , pushover curve was a straight line ,in fact truss element in this case dont consider nonlinear part of analysis but this pushover curve with force beam column element is a logical curve( have nonlinear part)
because of it ,i think that i should use another element for modeling BRB...
now i want to find difference between truss element , force beam column , corot truss...
thank you again

[saharnaz]

hi,
i've verified an experimental test for brb with this element. you should use truss element with elastic material for portions in brb that remain elastic and use truss element with nonlinear material for central portion of brb(yieilding core)

[alexsam]

Hi
how i can model BRB with corotTruss or forceBeamColumn element with steel02 material , infact i ask explain me how define nodes and plastic hinges in just BRB element....
please help...

Thank you

[longchelsea]

I also am having this question , there is no one to explain fears ? thank you