I have this model where I am adding dummy beam member to compensate for wall load. The system is supported on top with slab. I would like to ask if do I need to the dummy beam's nodes to my current floor diaphragm as I want my floor slab to act end to end of the column?
The nodes in the picture with color red are the ones that is currently included to the floor diaphragm.
Please forgive the illustration.Edit: I asked because when I added all nodes of the floor as a floor diaphragm, I think it gives very unusual moment diagram, whereas if only end to end, it gives proper type of moment diagram. Or is it because the diagram is meant to be like that?
If the model is stable with only the column nodes connected to the diaphragm, then that should be a fine solution. I suspect that the additional nodes are not at the same elevation at the column nodes. If you connect nodes at different elevations to a common diaphragm, then those nodes can resist moments directly from vertical loads. Some applications don't even permit such a diaphragm.
It is the same elevation as other nodes sir. I just want my floor to be rigid. Will it still act as rigid even if the nodes I selected for rigid diaphragms are the start and end nodes of each slab partition?
Also, what do you mean by "stable", thank you sir!
BY stable, I meant that it solves, it's not instable. The rigid offsets of the beams are probably leading to your odd moment diagrams, and I still suggest that the best approach is to apply the diaphragm only at column nodes.
Thank you for your answer sir, but even tho without offset, unknowingly adding floor diaphragm on a node (if I add another in between the span) leads to odd moment diagram. May I know how does STAAD computed the forces at the point of floor diaphragm node?