Ribbed (and waffle) slabs in Ram Concept

“Modeling” waffle slabs is easy. There are two basic approaches.

1. Define a thin flat slab, priority 1, on the mesh input standard plan, then define a system of deeper, crossing beams with say priority 5 left-right and Priority 6 north-south.
2. Or, define a single thick slab with priority 1, then define thinner rectangular coffers with a higher priority.

Either way, the resulting element plan is that same. 

The tricky part comes in defining design strips to effectively “Design”  all the beam segments without having unusual cross sections.  You can define bunches of short design strips between beams, but that can be overkill. Using strategically placed design sections in critical locations is often more to-the-point.

Ok, Thank you Seth...

Is the same concept for doing Multi-cell slab whit transversal diaphragms

and Voided Slab ?¿ or We have to do it modify stiffness coefficients?

If you are talking about a thin top slab and a thin bottom slab with air between them, that's beyond the scope of the program. Using modified material properties or modified slab behavior properties is a possible way to simulate such a voided slab, but the program only analyzes and designs solid slabs.

ok, Thank you Seth

regards