Retaining Walls
Retaining Walls
(OP)
If a retaining wall is backfilled prior to restraining the top, would the soil pressure be active? Specifically, I want to tie the top of the retaining wall to the slab. I assume the wall will tilt prior to restraint. So it seems it will be active. The cantilevered condition is the worst case here anyway even with the lower EFP.
Also, the CBC requires the EFP to extend to the bottom of the key. Is there any way to justify not applying this? Just from experience, the key depth required is unreasonable.
Also, the CBC requires the EFP to extend to the bottom of the key. Is there any way to justify not applying this? Just from experience, the key depth required is unreasonable.






RE: Retaining Walls
No legit manner that I am aware of but MANY engineers neglect it. However, from typical assumed soil loading profile it would be required. It's likely that your geotech gave you passive as "net passive" rather than "gross passive" so perhaps you can justify an increased passive pressure to help compensate.
RE: Retaining Walls
This is pretty much the exact reason I do everything I can to avoid a restrained top/bottom retaining wall. Contractors rarely pay attention to the shoring requirements in the documents and just start building. It's amazing more accidents haven't happened.
RE: Retaining Walls
Check out Eng-Tips Forum's Policies here:
FAQ731-376: Eng-Tips.com Forum Policies
RE: Retaining Walls
Once the wall moves (tilts) and active pressures are developed, the pressure should not increase if the wall is then restrained at the top. That is the theory. How that would hold up in the specific situation being discussed/built, is anyone's guess. For example, what happens if part or all of the backfill is subsequently excavated sometime in the future and then backfilled?
My advice, if the top of the wall is restrained; design it for at-rest pressures.
Mike Lambert