Inclusion of Self Weight for analysis

[Araj]

Hello !!!

How can I include the self weight of the element member for analysis in OpenSees ?

Is there any specific command for that ?

Thank you

With regards,
Aloke

[fmk]

it depends on the elements you are using .. at the moment some do and some don't .. what are you using?

[Araj]

I am using the "element nonlinearBeamColumn " and "element beamWithHinges" for the analysis.

[fmk]

these elements do not have a self-weight option .. to provide self-weight for these elements you can apply some uniform beam loads.

[kadirtopcu]

and how about the truss element and displacement beam column element?

[fmk]

nope. basically the continuum elements do, the line elements do not.

[hshoar]

Dear fmk,
Could we use uniform beam loads to impose weight for vertical elements, like columns? or brace elements?
Thanks.

[kadirtopcu]

Dear hshoar,
İf you find any answer for your question, could you please write here ? Because I am also confused about it.

[fmk]

yes. of course!

[kadirtopcu]

Dear fmk
When we apply uniform loads to braces, which direction sould we use ? because in local axes, it is not including downwards direction.

[lorcancon]

Hi all,

When working with a larger model, It may be useful to create a loop which will automatically apply self weight as a line load for all elements. Something like the following:

foreach elem [getEleTags] {
set area [lindex [eleResponse $elem section] 4]; # Here we need to get the area of element with tag "$elem"
set unitW 7.85; #For example
set Wz [expr $area*9.81*unitW]
pattern Plain 1 Linear{
eleLoad $elem -type -beamUniform $Wz
}
}

However, the "eleResponse" command only gives information about responses to loads. We require a command here which gives a list of element properties (e.g. stiffness, inertia, Area etc). Frank, maybe such a command already exists?

Regards,
Lorcan