Problem modelling composite slab

[Anonymous]

Hi all,

I've been trying to model a composite slab using comflor 60 trapezoidal decking to run a footfall analysis. I now have most of the structure running correctly I believe other than the composite behaviour. I've used offset beams but when I check the bending and shear in the beams some odd behaviour occurs.

Anyone have any idea on what's going wrong here?

Thanks,

J.

[Artur.Kosakowski]

Hi @Anonymous

Offsets are intended to model correctly the overall stiffness of the slab but due to the fact how they 'act' they should not be used when one needs explore results in beams. see e.g:

https://forums.autodesk.com/t5/robot-structural-analysis-forum/one-way-slab-with-offset-beams/td-p/5550026

For steel profile the alternative approach would be to model them below the panel (in the positions they are in a real structure) and connect them with the nodes of the mesh  with rigid links as shown here .

If I managed to answer your question(s) press the Accept as Solution button please. This will help other users to find solution(s) much faster. Thank you.

[Anonymous]

I've tried modelling the rigid links but it's still not transferring loads appropriately (sum of reactions is ok however).

I've attempted to simplify the model by using a rectangular slab rather than trapezoidal and altering its elastic modulus as per Section 6 of the SCI P354 publication on footfall analysis. The moment output still seems to be incorrect however.

Any help appreciated. I've read through the forum links you've provided but have hit a bit of brick wall.

Thanks.