topic Re: Foundation slab in Robot Structural Analysis Forum

Foundation slab

gvbrevit1 — Tue, 20 Sep 2022 07:20:01 GMT

Hello!

I designed a foundation slab with thickening around the perimeter.

I made the slab as two slabs of different thickness. How can two boards of different thicknesses be joined? If you go through the <Panel> option, only one thickness panel can be used there, and when connecting the slab, one thickness is defined.

Maybe there is another way to connect two foundation slabs of different thicknesses?

Thanks!

Re: Foundation slab

Simau — Tue, 20 Sep 2022 09:38:33 GMT

@gvbrevit1

Did you create the 2 thickness before using panel option?

Re: Foundation slab

gvbrevit1 — Tue, 20 Sep 2022 10:18:34 GMT

Hello.

If I understood the question correctly, then Yes, I first made panels of two thicknesses and then tried to connect.

Re: Foundation slab

Simau — Tue, 20 Sep 2022 10:40:38 GMT

Select panels one by one

Re: Foundation slab

gvbrevit1 — Tue, 20 Sep 2022 12:52:57 GMT

Thanks for the reply. But I still don't understand how you can select one by one. Because when selecting both panels, only one thickness can be defined... either TH30 or TH70. Then either one TH30 panel or one TH70 panel is formed when connected. Honestly, I don't understand why it's so difficult.

Re: Foundation slab

Simau — Tue, 20 Sep 2022 14:16:33 GMT

@gvbrevit1

Don't select both panels at once

Select panel 1216 and apply it thickness 1, then select panel 1258 with thickness 2

Re: Foundation slab

gvbrevit1 — Wed, 21 Sep 2022 08:44:51 GMT

Thanks for the reply. but it already does not connect panel Thickness 1 with panel Thickness 2 into a common single panel. They are still two separate panels, one with Thickness 1 properties, the other with Thickness 2 properties.

I also tried the option when the TH30 panel covers the TH70 panel.

But then the program throws the warning <overlapped panels>. Does it affect the calculation result?

Re: Foundation slab

Simau — Wed, 21 Sep 2022 09:27:40 GMT

You have geometric discrepancy in your panels.

Could you zip your model and share it

Re: Foundation slab

Rafacascudo — Wed, 21 Sep 2022 13:17:27 GMT

That's the wat it is. In your case ,you will never have a single panel with 2 different constant thicknesses.

But the 2 panels are connected anyway.

If the 2 panels are 2 concentric squares , just create the larger one with its thickness and then create the smaller one "over" it. RSA will understand and there will be no overlapped panels warning

Re: Foundation slab

gvbrevit1 — Wed, 21 Sep 2022 15:00:27 GMT

Hello. Thanks for the reply. <create the larger one with its thickness and then create the smaller one "over" it> means that if the upper panel is 300mm thick and the lower one is 400mm, then I place the lower panel 350mm lower than the upper one. See picture. I understand correctly?

Re: Foundation slab

Simau — Wed, 21 Sep 2022 17:47:51 GMT

Create first the external contour with 70 cm thickness, then the internal contour with 30cm thickness, you'll get something like the picture below

If you want to have the upper faces at the same level you may move down 20 cm the external panel using rigid links

Re: Foundation slab

gvbrevit1 — Thu, 22 Sep 2022 09:03:30 GMT

Hello. Thanks for the reply. Creating two panels like this will connect them (shown in red in the picture)?

I'm confused by the deflections, they're easier to control 🙂 After calculation, looking at <Results-maps>, panel deflections are like one common panel.

But when calculating <Slab-required reinforcement> and <Slab-provided reinforcement>, panel deflections are divided for each panel separately. And the reinforcement for each panel is also separated.

This is a bit worrying.. The question is whether when calculating in the <Slab-required (provided) reinforcement> section, each panel is calculated separately, not both together?

Re: Foundation slab

Simau — Thu, 22 Sep 2022 09:29:07 GMT

Creating two panels like this will connect them (shown in red in the picture)?

Yes

...panel deflections are like one common panel.

No.

It's one slab made of 2 panels. Why did you expect different deflection at the common edges?

But when calculating <Slab-required reinforcement> and <Slab-provided reinforcement>, panel deflections are divided for each panel separately. And the reinforcement for each panel is also separated.

This is a bit worrying.. The question is whether when calculating in the <Slab-required (provided) reinforcement> section, each panel is calculated separately, not both together?

The reinforcement is calculated for each panel according to its thickness and its internal forces.

Re: Foundation slab

gvbrevit1 — Thu, 22 Sep 2022 15:19:08 GMT

Thanks everyone for the replies. I think I understood your advice.

Re: Foundation slab

gvbrevit1 — Fri, 23 Sep 2022 15:21:59 GMT

Hello. I have another question. When calculating the coefficient K of the soil, the dimensions A and B must be specified for the slab. The real dimensions of the slab must be specified, for example A=70m, but B=32m? Or are there any restrictions, for example, the area cannot be larger than 10x10m.