RC WALL
RC WALL
(OP)
Hello, Im dealing with a manure pit (excuse my english) under stable for cows...
Im not really sure if I should use model B (see attached picture) when designing a RC wall.
Wall is loaded with horizontal soil pressures (outer side) and sometimes with water + manure (inner side).
It kinda bothers me because the wall is not connected with other walls by concrete slab (at the top) but with prefabricated concrete slabs with slots/openings. This slab lies on top of concrete corbel. The problem is that this prefabricated slab with slots doesnt offer horizontal support to the RC wall at the top so Im kinda concerned about designing RC wall with model B. Maybe a model A is better option?
On the other hand the RC wall is connected with concrete slab (left side of RC wall), which connects a wall with foundations...
What do you guys think/suggest? i think there will not be deflection at the top of the RC wall so I can use model B but im not sure. i dont want to mess this up since horizontal loads are not that small.

Im not really sure if I should use model B (see attached picture) when designing a RC wall.
Wall is loaded with horizontal soil pressures (outer side) and sometimes with water + manure (inner side).
It kinda bothers me because the wall is not connected with other walls by concrete slab (at the top) but with prefabricated concrete slabs with slots/openings. This slab lies on top of concrete corbel. The problem is that this prefabricated slab with slots doesnt offer horizontal support to the RC wall at the top so Im kinda concerned about designing RC wall with model B. Maybe a model A is better option?
On the other hand the RC wall is connected with concrete slab (left side of RC wall), which connects a wall with foundations...
What do you guys think/suggest? i think there will not be deflection at the top of the RC wall so I can use model B but im not sure. i dont want to mess this up since horizontal loads are not that small.







RE: RC WALL
RE: RC WALL
Dik
RE: RC WALL
RE: RC WALL
RE: RC WALL
2. The slab-on-grade on the other side of the wall can also provide lateral support provided the construction includes temporary shoring as wannabeSE mentions.
3. If the box isn't very long or wide in plan, the walls could possibly be designed for horizontal bending instead of vertical bending.
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RE: RC WALL
Dik
RE: RC WALL
This is assuming the slab on grade provides restraint at the top - which should be absolutely mandatory. No point removing redundancy for whatever reason with insitu concrete. And I'll take that opinion to the grave.
RE: RC WALL
Im hesitant to justify the exterior slab to brave the wall personally.
1) sequencing would require the wall be braced until the slab is cured, the contractor will likely not like this.
2) the slab appears to still be within the failure wedge of the soil so you would need to justify it as a deep beam spanning to the return walls.
3) 10 years down the line if the slab is removed your average contractor will likely not realize it was part of the retaining wall restraint as it's somewhat uncommon
If you can justify the precast slab of say have at it. I would think there could be a way for that. Or if you can justify the wall to span horizontally to the return walls that would be great. Otherwise, I'd design it as a cantilevered wall and backfill prior to placement of slabs. This will allow the wall to deflect and engage active pressure. You could also redundantly design as a propped cantilever as well.
RE: RC WALL
Edit- though your point about the proximity of the footing to the wall and failure wedge is a very good one. You may have swayed me
RE: RC WALL
To be clear, you started the thread saying the exact opposite.
And I do believe it's a component of good engineering practice to have an understanding of how the contractor will likely want to build it. Sure not everyone will be the same, but typical construction sequencing should be considered in design.
RE: RC WALL
Also my point (the one I actually said) was that in the temporary case of backfilling they might be sufficient.
Absolutely I agree. But I prefer a note ala 'contractor to ensure stability of structure during construction', rather than altering my design on possible outcomes. If they have a fancy idea they want to use to save themselves money, fine, I'll consider it and bill them for my time.
RE: RC WALL
If that's not the case and you can rationalize them for temporary support I would think you should be able to consider them permanent support as well. The load path needs to be in tact for either condition and if the load path is there and have the strength to support for temporary backfilling and compacting I would bet they would work for permanent loading as well.
RE: RC WALL
Using the slab-on-grad adjacent to the pit is questionable because the slab could be removed in the future without anyone realizing its importance to the stability of the pit walls.
In my region, these types of buildings (usually hog confinement barns) do require the removal of the slotted precast planks occasionally (not always) so relying on them isn't a good idea.
So that really just leaves a cantilevered retaining wall type structure for the pits.
And based on proportions in the sketch above, the influence line at 45 degrees from the bottom edge of the main building foundation isn't all that influential on the pit walls in any case.
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RE: RC WALL
RE: RC WALL
Should you consider additional wall and floor thickness, concrete cover, concrete strength or other measures to combat the corrosive effects of wet manure?
BA
RE: RC WALL
RE: RC WALL
RE: RC WALL