Reduced results for core walls and the center of rigidity

[Anonymous]

Hi there,

I'm modelling a building and I want to extract some reduced forces for the structural core to provide for foundation design. I know using "diagrams for buildings" I can extract reduced forces about G ("the center of gravity of a story") but I want to reduce the forces in the core walls only about the center of mass of the core walls for a pile cap design.

I have defined the walls in my core as "core walls" and run the model. However doing this moved the center of rigidity from previously being in the same place as the "center of gravity of a story", to now be outside the core walls i have defined which does not make sense. Below is a screenshot showing the center of mass (red) and the new center of rigidity (blue). Your help info states that the core walls do effect the calculation of the center of rigidity but not how they effect it: from the below it looks like the core walls are ignored in the calculation of the center of rigidity for a story? is this correct?

To check that the "Core walls" tab of the "diagrams for buildings" is reducing the forces correctly, I'd like to see the centre of mass of the core walls. Can I get the coordinates for this without having to delete all the other elements in the model apart from the core walls and re-analysing?

And final quick questions: how is the center of rigidity calculated? Is it parallel axis theorem (similar to center of mass) but including the material stiffness? And if that is the case can I reduce results in the core walls about the center of rigidity rather than the center of mass? (without calculating this manually)

Thank you!

[piperr]

Autodesk Gents and Ladies this is getting ridiculous. The post has 5 years !

Should we get a paper signed by 1 zillion engineers to fix the bloody RSA ?????