unusual diagram

[petroniuchacz]

Greetings,

I'm new to RSA. I'm designing a RC structure and I got an unusual diagram of bending moment for a beam - positive bending moment over a wall. Could you please tell me what may be the reason of this?

[Artur.Kosakowski]

Check the deformation of the model in this area.

[petroniuchacz]

I'm adding 2 more screenshots, the 1st one is the case I posted previous, in the 2nd one I added a rigid support to the wall. Both seem to be incorrect.

[Artur.Kosakowski]

Why do you consider them to be incorrect? On the top picture as far as I can see there is displacement in the middle of a bar which is 0 on the bottom one after adding a support.

[petroniuchacz]

I'm not experieced, but I would expect something

[t.sautierr]

it seems your beams act like this ? with something quite soft for the spring

[petroniuchacz]

Please take a look on the diagrams I posted above. They make something like this

[t.sautierr]

could you attach your model, because I see what is wrong to you.

[petroniuchacz]

Sure.

[t.sautierr]

This effect is due to the difference of span between the walls (twice as small) compared to the span between columns -> the span between the walls have positive deflection (upwards) so adding the wall create an element thats maintain the beam downards and so loads on the beam is not sufficient to "make" so mment negative.

You can check by having a test loads case were you load only the beam, you will see it reacts as you are familiar or make release at the end of beam 122 and the effect will disappear.