rigid diaphragm in 2D frame in opensees

[goase66]

how i model rigid diaphragm in 2d frame ? should i use equaldof command ?

[vesna]

if your beams are elastic equaldof will work.

[goase66]

vesna wrote:
> if your beams are elastic equaldof will work.
"rigid diaphragm command " in 2D frames does not work , it works in 3D issues , so i have modeling 2D frame with 3 bay and 3 story , and i try to rigid diaphragm in every floor that all of nodes in every floor have the same displacement in x direction , my beam and column are element nonlinear beamcolumn , for example in one floor we have 4 nodes that their lables are 21 , 22 , 23 , 24 and i want to model rigid diaphragm , to have same displcements in x direction i write
equalDOF 21 22 1
equalDOF 21 23 1
equalDOF 21 24 1
but when i run opensees it shows error , is there other way to solve it by other command ? plz hlep , thanks

[goase66]

"rigid diaphragm command " in 2D frames does not work , it works in 3D issues , so i have modeling 2D frame with 3 bay and 3 story , and i try to rigid diaphragm in every floor that all of nodes in every floor have the same displacement in x direction , my beam and column are element nonlinear beamcolumn , for example in one floor we have 4 nodes that their lables are 21 , 22 , 23 , 24 and i want to model rigid diaphragm , to have same displcements in x direction i write
equalDOF 21 22 1
equalDOF 21 23 1
equalDOF 21 24 1
but when i run opensees it shows error , is there other way to solve it by other command ? plz hlep , thanks

[vesna]

When using nonlinear elements equaldof is not the right command to use. To simulate the diaphragm effect you can add truss elements (between the same nodes where you have your nonlinear elements) with a stiffness of the diaphragm.

[goase66]

hi vesna
instead of your suggestion , i write "rigid link bar " ,

" rigidLink $type $masterNodeTag $slaveNodeTag "
bar only the translational degree-of-freedom will be constrained to be exactly the same as those at the master node
for before example
rigidlink bar 21 22
rigidlink bar 21 23
rigidlink bar 21 24
i think it works , and it cause that all of the nodes in one floor have the same displacements , what is your idea ?

[vesna]

you can achieve the same displacements this way but if you look at the axial forces in the beams you will see unreasonable values.

[goase66]

when i model rigid diaphragm in one floor , the axial forces in the beam correspond to that floor have neglect force ,i run my model , i checked my axial force in beams , and this force is neglec ,