Setting Load Bearing Wall on the Edge of strip footing 2

[Iasonasx]

I have never done this before and the argument was never an issue until today. The architect wants the wall to be on the edge of the footing. That throws the 2'-2" strip footing off balance, having higher stress outside and going beyond the allowable soil pressure. I wonder if there is a suggested solution. I was thinking about arranging the reinforcement to make it act like "infinitely" stiff moment connection. I just never encounter this type of argument before. I hope someone has a simple solution suggested.
Thank you

 

[phamENG]

Look into "property line retaining walls." It's common on zero set back lots where the wall can be on the property line but the footing can't go past it.

 

[jayrod12]

Make the footing bigger until the bearing pressure is below the allowable. There really isn't a better solution unfortunately. Making it moment stiff really doesn't do much to help the situation. The vertical load is still there and the eccentricity still exists.

And if you're thinking that making it a moment connection would allow you to use the backfill pressure as a restoring moment for the eccentricity, I'd be hesitant to do that. You have no control what they do in the future regarding the backfill heights and materials around the perimeter.

 

[Tomfh]

Design it for the eccentric load. You can also add some perpendicular strips to rectify the moment if required. They’re effectively outriggers to stabilise your footing the same as a canoe outrigger stabilises an unstable canoe. A way of substantially widening the overturning footprint without necessarily widening the whole footing.

 

[dhengr]

Iasonasx:
Is it a property line issue or is it just another goofy Arch. issue? What are the exterior (and internal) conditions around, alongside this wall and footing? Show the actual details For the design team concept to actually work, you do have to be able to question dumb Arch. details and ideas and explain the pros and cons of each condition, from the structural standpoint, or things would get even crazier than they are now. Your only function as a Structural Engineer is not just to make other’s stupid ideas work, at less cost and effort on their part. You do have to do something to counteract the eccentricity of the loads on the footing. As Jayrod12 suggests, you could make the footing more massive (wider and thicker) until the sum of the loads on it fall nearer its center, for better bearing distribution. You could run tie beams into interior column footings to take the moment (the eccentricity) on the exterior ftg. You could run a reinforced pier or col. from the footing up to the first fl. and tie the top into the first fl. diaphragm. That entire ext. wall could be ‘L’ shaped, with moment steel down at the ftg. to counteract the eccentricity moment.

 

[Iasonasx]

dhengr, it is not really that "goofy" if you think about it financially and what he wanted to achieve. He wants to have a monolithic slab so that we end up having just a single pour in a simple way to minimize costs. I do see a point, but to me that is only going to lead to many more expenses as in material and labor I see it. I came up with designs having reinforcements to make the thing act essentially like a retaining wall, and it surely will cost more in the end. I showed him my ideas, and he realized that it was better to play it safe and easy with the initial design I had. Essentially, I was doing things like the way Tomfh and dhengr suggest and maybe going a little heavy on it too. I placed two longitudinal rebars in the bottom of the footing spreading out @ 3" Clear Cover, and two on the top that were within the footprint of the wall, and tied them with #4 stirrups. So I essentially triangulated the form of the reinforcement, and I had rebars coming down the cmu wall and turning perpendicularly into the building's interior. I think that is what dhengr suggests, making the wall like an "L" shape. I am sure it would work that way but it would be way more costly because of much more material and labor.
I want to thank everyone for your input.

 

[Ron]

For a monolithic slab this condition is common. Widen the thickened edge and tie back to the slab.