Dear Sir,
I need to automatically design R.C. foundation supporting R.C. shear wall in a building which has been modeled using the RSA 2012. The shear wall base edge is pinned (linear support).
is there a way to design automatically the R.C. foundation under the shear wall as we made for the R.C. columns?
or we must manually enter the reduced forces of the shear wall in the R.C. foundation module?
Your help is very appreciated.
You can try to use the approach shown on the attached picture.
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It is a safe solution for wall with normal load.
but what can we do if we have moment as for for shear wall in the building?
(reduced moments due to seismic loads for example)
regards,
Wassim
I would adopt the same approach but after examining the values of reactions I would select one of nodes close to the ends of the wall (larger values of the vertical reactions due to in-plane moments). Of course this is when you want to have the same width and reinforcement along the entire foundation. Otherwise I would make the design selecting number of nodes along the wall adjusting the L values so that they correspond to each of the segment I intend to design.
Another option is to design the foundation against a group of loads (can be used to have the same foundation for several columns as well) by means of the grouping option. In such case the values of reaction from each of the imported nodes will be used in the design process. Mind that the values of imported reactions should be modified based on the distance of the neighboring nodes (unless the mesh size is exactly 1m and the side nodes are not selected )
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Dear Artur,
If I want to design the RC wall with the same footing width and depth.
The moment can produce compression in one edge and uplift in the other.
Is there a way to design this type of footing simply or we must then input the reduced loads of the panels?
thank you.
Wassim
My understanding is that the reduced moment is what actually caused vertical reactions along a wall to differ. I think the approach I described in my previous answer should be just what you need. Of course any other ideas from the user's of the forum are welcomed.
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Hello Artur,
Why could you not use a horizontal shell member with elastic supports to suit ground conditions with pin connection to elimnate moments?
Geoff
I'm sorry but I'm not sure if I understand you correctly. As far as I understand you want to replace pinned supports defined at the bottom edge of the panel (wall) with the horizontal panel on elastic ground. If yes the in-plane bending will be still there and to avoid out of plane bending you would need to define linear release at the bottom edge of the wall. Anyway if you create a foundation under the wall as the horizontal panel you can calculate reinforcement using the RC Slab design module but mind that no shear (punching) verification will be done.
Thanks Artur,
I have used this method for retaining walls and have checked shear by hand, of course with retaining walls there is no need usually to introduce the pin at slab wall junction.
Geoff
In such case the values of reaction from each of the imported nodes will be used in the design process. Mind that the values of imported reactions should be modified based on the distance of the neighboring nodes (unless the mesh size is exactly 1m and the side nodes are not selected ...
Artur
How would one set about modifying imported reactions in the scenario described above?
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