Split Walls By Level

[Dimitri Harvalias]

As more consultants are starting to buy into the BIM approach we are finding some conflicting approaches regarding how our models are constructed.
In order to make our models more efficient we (the architect side of the equation) have been building walls and columns as continuous elements spanning multiple levels. The logic being, if it's the same for 8 floors why have 8 objects to track and manage when one represents it just as easily.
When you copy/monitor a linked Revt Building (RB) model into RS you have the option to Split columns by level. This allows structural to do there analysis on a floor by floor basis and it also allows architects working in RB to mode columns as continuous elements spanning multiple floors.
Having spoken with structural engineers recently they would prefer to have the option of splitting walls on a floor by floor basis as well. RS can't do that with the linked file so we are left with two options. Either make our architectural model less efficient or have structural duplicate our efforts and model the structural elements in RS.

Does anyone know why RS does not have this ability? How is everyone out there working with a complete building model with consultants? Anyone have a better suggestion?

[Tom Weir]

Hi,
I have never split columns level by level on any of my projects in Revit Structure. I show them realistically, splicing 3'-6" above every second level. For an eight story building the column sizes will change as you go up the builidng most likely, so one would not use a single column object. I try to model like it is built...
When the columns are exported via integration link in this fashion I am not sure how it is handled by the analysis prorgram though.

Tom Weir
Los ANgeles

[Dimitri Harvalias]

For an eight story building the column sizes will change as you go up the builidng most likely, so one would not use a single column object.

That's a good point Tom. I'm referring to concrete structures more than steel and on a 30 storey tower we would likely have only 3-4 column size changes as we go up the structure and I would normally have it modeled as 3-4 continuous columns reflecting those size changes.

Without getting into a structures lesson here, when doing the analytical model for a concrete building doesn't the analysis software see that column as going from floor to floor even though the rebar cage is spliced at 3' above the floor level?

The real point I'm trying to make here is that in order to make the 'Total Building Model' work, Autodesk has to realize how the different parties involved are using the software and then make it work together once the models are being linked.

Thanks for the reply. Any other takers? How many of you are working as an All Revit team on projects?

[Scott Hammond]

You are correct, we do have to realize how the different parties are using the software. We encourage your input and comments and I will make sure to pass them along to the team.

[Paul Andersen]

I too, as Tom has already stated, prefer to model the physical / graphical model as it would actually be constructed. Revit Structure, the API Link to the Analytical Software, and or the Analytical Software itself should be able to break up the analytical (stick) model (by level or however it is required to analyze the given structure correctly) without damage to the continuity of the physical / graphical model while still maintaining the ability to seamlessly update each other throughout the duration of the project.

The idea then being that the physical / graphical model is an accurate representation of the building and all of its individual components which can hopefully be better leveraged as the basis for the fabricator's model in the near future.

[Jos Arpink]

Dimitri, thanks for raising this thread.

Concrete hi-rise structures are our bread and butter. We have adopted the approach of modeling walls and columns lift-by-lift, floor-by-floor...just as they are built. When we first start our model, it is usually prior to the analysis having been done, and so we won't know at which levels the core walls reduce in thickness, or the columns reduce in size...but we know that at some point they will. Changing family types at any level(s) is easy.

We also use Revit's ODBC export feature to generate quantity take-off spreadsheets. Since each of our walls and columns are uniquely level-based, it's very easy to see what's happening to our quantities as we go up the tower. If walls and columns pass through multiple levels, this aspect of the output is lost.

I've had this discussion with several architects now, as we begin to collaborate in Revit. A common understanding, and modeling approach, will be key to the effective use of Revit's copy/monitor feature.

My 2c

[Tom Weir]

Hi,
I have been doing wood structures (with platform framing), level by level. In my first few tries I started with wood framed shear walls that went from bottom to top. Now I have a wood framed shear wall with sheathing on the side, and top and bottom plates as part of the wall type, and go level by level...which is how it would be built in the field (back to that point again).

Tom

[david_peterson]

Revit Structure, the API Link to the Analytical Software, and or the Analytical Software itself should be able to break up the analytical (stick) model (by level or however it is required to analyze the given structure correctly) without damage to the continuity of the physical / graphical model while still maintaining the ability to seamlessly update each other throughout the duration of the project.

I've just done this with Risa Floor beta 2.19. It worked. I've also gotten my model out to Risa 3D this way, with out having to split columns floor by floor. It was only a 2 story building so I don't have splices. Now, if only Ram could catch on to this ~hint~

[Ultrabags]

I too, as Tom has already stated, prefer to model the physical / graphical model as it would actually be constructed. Revit Structure, the API Link to the Analytical Software, and or the Analytical Software itself should be able to break up the analytical (stick) model (by level or however it is required to analyze the given structure correctly) without damage to the continuity of the physical / graphical model while still maintaining the ability to seamlessly update each other throughout the duration of the project.

The idea then being that the physical / graphical model is an accurate representation of the building and all of its individual components which can hopefully be better leveraged as the basis for the fabricator's model in the near future.

Has this approach been successful when utilizing 3rd party software such as Risa 3D? I, like you and Tom, prefer to model the project as accurately as possible. I'm starting our company's first official RS project and I am not sure if this would be a major problem with the analyzing process of the structure.

[david_peterson]

From the little bit I've played with it, it should bring them in as plates.

"All structural walls except "non_bearing" are supported and mapped to 3 or 4 onde plates in Risa 3d. Structural wal thickness mapes to the plate thickness, and the first listed General material type is assigned. Doors and windows are not support at this time.
RS structural walls map tp once plate each in risa 3d. The user will generally need to sub-mesh each wall panel either manually or using the automesh tool. (Which I believe is a option in the export to Risa 3d)......"
Or at least this is what the Risa white paper tells you. Risa being node base dosen't seem to care how you model things. Just be sure that your Analytical model in revit is correct before you export. RS seems to "Automatically" place things and isn't always that consistant in it's placement.
ie I'd model it as how it's built.