Friday, April 10, 2009

RE: Retaining wall footing resultant CBC

Can someone cite a reference establishing EFP as soil density * Ka (active) and NOT soil density * ko (at-rest)?
 
Thanks,
 
Michel
-----Original Message-----
From: Michael Hemstad [mailto:mhemstad@mbjeng.com]
Sent: Friday, April 10, 2009 7:34 AM
To: seaint@seaint.org
Subject: Retaining wall footing resultant CBC

I agree with Steve.  When I design retaining walls, I put At-rest pressure on the back face.  Remember that the wall has to move slightly to engage the soil skeleton enough to apply only Active-level forces.  In my mind, the next time it rains, the soil settles and applies at-rest level force.  Then, if the wall can move again, the soil skeleton is re-mobilized and we're back to active pressure.
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