roof / wall / slab intersections

[Anonymous]

I am piloting a project on archicad at my office and I am having reasonable success so far. Lots and lots to learn in order to move into a modelling mindset rather than drafting...

I have attached two images; one of a wall to roof junction and one of a wall to slab junction. I really need advice on how to approach these in archicad.

For instance, where the wall meets the slab - should I bring a flat slab to the concrete block and then create a profile for the notched bit of slab and the footing and model that as a complex wall profile? Do I need to create separate lower wall for where the brick and insulation run lower than the concrete block, or can that be achieved via priorities.... etc.

Same sort of questions for the coping and insulated gutter on the wall / roof junction.

Any and all help MUCH appreciated!

Thanks,
derek

[Anonymous]

...and the other image...

[Anonymous]

1. Wall to roof junction...... Complex profile for coping and insulated gutter if the gutter has no slope. Otherwise use 3D Mesh for the gutter.


2. Wall to slab junction....... Complex profile for the slab with little of SEO (Solid Element Operation) between the slab and the wall.

[Karl Ottenstein]

For the wall-slab intersection, I disagree with the profile that andro55 suggests - but only as a personal opinion. There are dozens of ways of doing what you want.

See attached for my suggestion. I would model the slab as you suggest - extending the full width. (I would even make the slab a composite, showing the rigid insulation underneath it as a separate skin. But, some people prefer to model this as a separate slab.)

The bit outlined in red could be created as a complex profile - both the concrete and the insulation. Optionally, you could include the footing in the same profile. Depends on how likely you think bits and pieces would be re-used and/or sizes of things might change. If you use this CP with the Wall Tool, note that the origin ('x' symbol) in the complex profile editor window corresponds to the reference line of the wall - and so you should place your profile to position the origin at a point that is meaningful to you. For example, if you want to magic wand the 'walls' for the footing under the slab, then the user origin should be where the slab edge would meet the footing profile. If you want to magic wand the footing structure at the edge of the outside brick face, then position your profile there. Just makes it easier.

Slab / profile insulation intersection: Note that if you model the slab as a composite, with the rigid insulation skin below - that you will need to do a solid element subtract of your footing from the slab to remove the insulation that would otherwise run through the concrete of the profile. If you model the sub-slab insulation separately, it's no big deal.

Wall-slab intersection / notch (blue circle): You can solid element subtract your slab from the wall, to create the notch. In this case, that seems the easiest thing to do. Alternatively, you can create the wall using a complex profile that has a notch in the profile corresponding to the slab. I prefer the first method (subtract) since it gives you more flexibility as you move from schematic design to CD, since if engineering specifies a different slab thickness, everything will adjust automatically. (A complex profile wall can only have one 'stretchy' height region - so the notch would not dynamically change size to accommodate a change in slab thickness.)

Just a few of the many ways to proceed...

Cheers,
Karl

[Anonymous]

These suggestions are really helpful. Thank you both very much!

We're working on quite a complex secondary school, and this excerpt is from a simple stand alone structure. I'll probably have many more questions, but I can already see how these tips will help us in other areas.

cheers.
derek

[Anonymous]

Alright - two more questions based on the same images;

1. for the roof, would it be advisable to do the metal decking as a custom profile and the insulation and standing seam as part of a composite? (I cannot find an appropriate fill for the composite which looks like decking, and furthermore even if there was I assume it would display the same no matter which way it was cut, wouldn't it?)

2. which storey would you advise putting the slab footing on? ground or a storey below?

cheers,
derek

[Karl Ottenstein]

macitect wrote:
Alright - two more questions based on the same images;

1. for the roof, would it be advisable to do the metal decking as a custom profile and the insulation and standing seam as part of a composite? (I cannot find an appropriate fill for the composite which looks like decking, and furthermore even if there was I assume it would display the same no matter which way it was cut, wouldn't it?)

Once again, dozens of ways of approaching this, particularly if your are at schematic vs document stage. But, yes, the biggest hassle is that if you do the metal deck, standing seam, or the purlins (look like purlins anyway - could just be standing seam clips/tie-downs though?) with a fill rather than actual modeled elements, the display will be the same regardless of the cut direction, which will be wrong.

There is a standing seam "roof accessory" object (Help > Downloads > Accessories) that can take care of the metal roofing.

If you model the metal decking as a profiled element, it will increase the polygon count of the model, but not terribly. For small scale or full building sections, it will be too busy and turn to 'mud' on the drawing - so you might turn its layer off for such things - and instead turn on a simple 'massing' roof plane.

If you are not doing interior 3D views that would show the metal decking, and you only have one or two enlarged details such as you show, one can always just model with a roof slab mass and show the decking with (gulp!) 2D linework in the large details. If you have many enlarged details - that are live from the model - then modeling the decking will save time and errors in the long run.

2. which storey would you advise putting the slab footing on? ground or a storey below?

Personally, I put things like that on a separate foundation story below. But, I also use structural (S-) layers for them, so layer control could also let them successfully stay on the ground story.

I'm not in an area where shallow footings are an option because of frost depth. The actual depth of footings varies significantly by location and soil, so I find that a separate story lets me raise or lower the footings via story height without any other editing.

There's no wrong way... until you discover that the way you chose results in lots of editing when a change comes along. 😉 Keep things as simple as possible given the most realistic scenarios you have for how the project might evolve... or how likely the current project is to become a template for future, similar projects.

Cheers,
Karl

[Anonymous]

Karl wrote:

macitect wrote:
Alright - two more questions based on the same images;

1. for the roof, would it be advisable to do the metal decking as a custom profile and the insulation and standing seam as part of a composite?

There is a standing seam "roof accessory" object (Help > Downloads > Accessories) that can take care of the metal roofing.

If you model the metal decking as a profiled element, it will increase the polygon count of the model, but not terribly. For small scale or full building sections, it will be too busy and turn to 'mud' on the drawing - so you might turn its layer off for such things - and instead turn on a simple 'massing' roof plane.

Cheers,
Karl

Cadimage's Coverings tool is very good (does all wall coverings and claddings too) and has an option to show in simple form to reduce polygon count.