Garage slab to wall detail

[JStructsteel]

Designing a retaining wall for a garage (its a sloping site, so wall is retaining on inside) and wanted to use slab to pin the top of the wall.

My thought is just bars bent out of the top, and pour up to the wall, but worried about it will restrain the slab too much. Would you put expansion joint around anyway, to give it some breathing room?

Anyone have a better detail?

 

[Celt83]

...and wanted to use slab to pin the top of the wall.

do you have enough slab to build up friction resistance for top of wall reaction?

If it's a large delta from inside to out I've done a thickened slab with a shelf on the wall to account for poor compaction of the build up + some settlement as the wall creeps outward. Usually don't tie them together, but hooked bar with a joint gives some vertical flexibility and could accomplish what your after.

My Personal Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

Open Source Structural GitHub Group:

https://github.com/open-struct-engineer

 

[JStructsteel]

Its a 10' wall. Have not checked the reactions yet, hopefully I can, otherwise will have to put bars all the way across.

I think a shelf makes sense, and reinforce the slab or thicken at the edge to give it a bit more strength.

Thanks

 

[KootK]

When it's not too punitive to do so, My default for this kind of situation is to leave the retaining wall as a cantilevered element (at rest pressure) and not tie it to the SOG. Unless the shelf element has a low span to depth ratio, you'll wind up dragging some tension into the SOG behind the shelf. That tension, in your typical 3.5"/WWF reinforcement garage SOG, has the potential to cause cracking issues that may draw the owner's ire. I like the tie-back system better if I can get a solid 4" with #4 @ 18". It's a lesser thing but I also don't love having the stability of the superstructure dependent on an element like an SOG that many owners will feel at liberty to mess with. The shelf does help in this regard.

See below for some detailing ideas. Technically, you have to develop the dowel either side of the shear friction joint so probably small bars and a longitudinal one in the knuckle.

 

[KootK]

I did one of these in Monterey last fall. Another consideration is construction sequencing. The contractor will have to back fill and compact on the inside of the wall before the SOG goes in. This can be got around with temporary wall bracing but that'll only happen if you ask for it to happen in many instances.

I found the question of where to put the wall drain interesting. I went with inside the wall because that's the side where I expected potential hydraulic head to develop. On the other hand, I see most of the non-capillary water build up here occurring from overland flow from the exterior. In that sense, I almost feel that exterior drainage would provide better protection to the footing bearing surface.