One big footing for shear walls and columns

[Enger2022]

Hi engineers,

For shear walls and columns as per the sketch below. I plan to make a big footing for them.
Could you please share some thoughts on how to design it? Thank you!

 

[dijonnaise]

We tend to model raft footings using 2-way slab analysis software w/ an assigned modulus of subgrade reaction. Make sure your soil springs are compression only.

 

[Just Some Nerd]

We tend to model raft footings using 2-way slab analysis software w/ an assigned modulus of subgrade reaction. Make sure your soil springs are compression only.

This is basically what we do.

If you've got a 3D model set up already and really feel like dumbing it down / simplifying things to the extreme, simply looking at moments/bearing pressures in a footing shell directly and assigning reinforcement to meet the required capacity is also a route that can be taken, though we only use that for comparison's sake.

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Why yes, I do in fact have no idea what I'm talking about

 

[Enger2022]

Thanks for the reply.
Can I ask what program you are using and how you apply the moment on the walls?
Mf and Vf are at the top of the wall.

 

[kjm93]

CSI SAFE is what I use. I resolve moments into discrete point loads along the length of the wall. A useful feature is exporting reactions/load combinations from ETABS into SAFE and then modelling your mat. You typically just need vertical loads from gravity and overturning to design the mat.