rigidDiaphragm

[Mohammadf]

Hi Dear all
I have a 3D steel frame with pined connections at two ends of beams. for this purpose I have multiple nodes in one position and constraint them together with equalDOF command. now I want to join these nodes with rigidDiaphragm command at each level. how should I do this. if I use principal nodes (column Nodes) in the rigidDiaphragm command when I see display of the model, nodes act individually and are separate from each other. so whats my problem?
as second question: what is the order of defining following parameters in a script.
A: equalDOF for same coordinate nodes
B: fix command for center of mass
C: rigidDiaphragm command

Best

[emjac]

Have you looked at this example? http://opensees.berkeley.edu/wiki/index ... l_Building

Otherwise, post your script. It is hard to understand what is happening from your description.

[Mohammadf]

dear emjac
As I illustereted before I have a pined frame not MRF. your example is a MRF. becuase of that I have to define more than one node in a same coordinate and link them toghater by equalDOF command to make pined connection. my question is which node have to peresent in the rigidDiaphragm command. for example:

node 1 0.0 0.0 4.0
node 2 2.0 0.0 4.0
node 3 2.0 2.0 4.0
node 4 0.0 2.0 4.0

# Center Node
node 5 1.0 1.0 4.0

# Pin Nodes
node 101 0.0 0.0 4.0
node 102 2.0 0.0 4.0
node 103 2.0 2.0 4.0
node 104 0.0 2.0 4.0

equalDOF 1 101 1 2 3 4 6
equalDOF 2 102 1 2 3 4 6
equalDOF 3 103 1 2 3 4 6
equalDOF 4 104 1 2 3 4 6

fix 5 0 0 1 1 1 0
rigidDiaphragm 3 5 1 2 3 4
or ?
rigidDiaphragm 3 5 101 102 103 104

Best

[fmk]

it is typical to use the center node in the rigidDiaphragm command.

with all your constraints you may need to use the Penalty method to enforce the constraints