Top of Steel or Top of Concrete? Both?

[scowsert]

We are drawing a wide flange framing building with concrete floors. I created the levels at Top of Concrete (TOC) and dropped the beams below. I suppose I could have just as easily created the levels at Top of Steel (TOS) and raised the concrete floor. Or... I could have created both levels. What approach do you take and why? Is one system better then the other? How about linking with Architectural Revit Models?

I wasn't able to find this topic on here. I'm sure it must have been addressed before.

Thanks Sage

[Paul Andersen]

Here is a discussion related to your question.

We prefer to use as few levels as possible (typically 1 level per physical floor of the structure). For steel I prefer top of steel and offset the structural slab up by its thickness. This avoids the need to offset all of your framing.

In the link above Scott outlines a nice method for copy monitoring the Architect's levels with an offset. We typically start with very limited information from the architect so another approach is to create your own levels based on your preference. At some point when you link in the Architect's model you can copy monitor their levels (leaving them at their current elevation) and lock a dimension to your level. This way if the floor heights change per the Architect your structure will go along for the ride.

For almost everything else (concrete structures, foundations etc.) we use top of structural slab.

[scowsert]

Thanks for that link Paul I knew it had to be around here some place.