Stacked Wall as Footing

[cek]

I'm thinking about using the stacked wall with a wall level to represent the footing.

I know I'm going to have some issues at step conditions and where spreadfootings occur for column loads but other than those are their any other down sides to this approach such as estimating?

Thanks

[twiceroadsfool]

Plenty.

First, they will now respond as walls, and not as footings. For lineweights, visibility controls (overrides or view templates for dashed lines), catagories, filtering (but i suppose you can filter by wall type name... ugh), scheduling, etc. Now theyre walls, not footings.

[cek]

Hmmm, Since my structural engineer is showing them in his Revit model / drawings the only place they appear in my drawings are in my sections / wall sections. As structural elements we aren't detailing them. Only using them as a graphical pointer to the structural drawings.

I guess I need to weigh the time savings in a stacked wall against the filtering requirements in the wall schedule but I think the big kicker is that it appears the estimating program may see the footing differently. I need to run this by the Navisworks people here to see what the issues are.

That raises another question of how Navisworks differentiates between the architectural model and the consultants models when there are duplicate representations of building elements. In the architectural model they are only graphic representations but in the consultants models they are performance (calculation driving) representations.

[cek]

It also appears that my "instance" wall tag will not operate properly with the stacked wall. It does however work with a "type" wall tag. This plays havoc with the ability to separately "Mark" two walls of the same type that have different characteristics (like height termination) in my schedule.

Has this limitation been addressed in 2010?

It looks like I will have to create duplicate walls for different height terminations if I plan to use this parameter in my schedule.

[twiceroadsfool]

Im not sure why you wouldnt just use the Wall Foundation tool for foundations. It takes seconds to put them on.

In Navisworks, the different models show up as seperate entities, so youll either remove yours with a selection or search set, or exclude it from the export anyway. One way or the other. But, even in navisworks it will show up as a *wall.* For me/us, that is very undesireable.

[cek]

Aaron,

I agree with your assessment. If the wall representing the footing is not independent I can't turn it off before saving out for Navisworks consequently it sounds like NW would identify the Wall(footing) conflict with the Structural models foundation.

[twiceroadsfool]

You can still turn it off, by hiding it in the view, and exporting to NW by view, instead of exporting the entire model. It will identify the conflict in Clash detection, but its a make believe clash. I mean, youre both modeling the same element. In those cases i usually eliminate the "representative" version before getting to NW.

But in my humble opinion, its not about a "graphical representation" in a Revit model. Objects are objects. I wouldnt want doors made from slim wall types, i wouldnt want windows made from doors, etc. Foundations are foundations, and you can take advantage of them more if theyre made using the correct tools. Plus, weve taken more time talking about it n this thread than it would take to make them out of foundations. :)

[dgreen.49364]

Question...if the structural engineer is showing them in his model, why are you re-creating them at all?

[archjake]

Carl,

It sounds like you're heading down the same road I took when I discovered the stacked wall feature. This may work for some cases and makes sense in theory but in practice I found that it is a no-go strategy. I didn't have questions with regard to clash detection or an engineers model but I have tried using the following:

Use a separate stacked wall for spread footing and stem wall conditions. This works well if you only have spread footings.

Use standard walls with the correct "Bearing" property for spread and isolated footings.

My current method which I have found works the best has been to create structural footing families. They are controlled with instance parameters to control length, and a type parameter for width (which works nicely for scheduling). Spread footings, toe downs, isolated, spread footings with a stem wall can all be built the same. They can also be scheduled if you do your own structural documentation or the documentation for your consultant. Geometry and family types work great. Getting a dashed representation on a foundation plan view works well for some of these families but others like the toe down can be problematic due to where the geometry meets the slab. The other nice thing about these is they geometry automatically cleans up where they intersect. If you ever run into a on-off situation an in-place family will clean up and represent the same as the pre-made footing families.

Good luck.