Flexible diaphragm interaction

[Chaymaa]

Hello STKO team,

I’m trying to model a two-story masonry building, with a wooden flexible diaphragm. What are the constraints that I must consider in my model to represent the flexible floor?

P.S: I’m using the Equivalent Frame Modelling approach

Many thanks in advance!

[Clarabella]

If you want to model the in-plane stiffness either membrane elements or truss/beam elements. The membrane stiffness should be calculated to reproduce the real in-plane stiffness of the slab you are modeling
Regards

[Chaymaa]

Hi Clarabella,

The diaphragm I’m trying to model is a flexible floor, made of wooden beams. I don’t want to model the beam elements; I just want to take into account the walls connection that assures the slab. That’s why I was wondering which constraints I must consider to represent this link.

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Like in the case of a rigid diaphragm, we define a node-to-node interaction, to relate the center of gravity of the floor masses to the rest of the nodes so that they undergo the same stresses. What would be the appropriate interaction for a flexible one (Node to node link / Node to element link / General link)?

Many thanks in advance!

[Clarabella]

Hi Chaymaa,
you can either use an equal degree of freedom constraint. In this case, you need to connect the opposite node of the beams imposing the same displacement along the beams' axis.
Otherwise, you could model directly the beams of the floors.
However, the piers are already connected with rigid constraints, so the wall connections should not affect the model behavior. Try with and without the result should not change