When the at-rest condition should it be applied?
When the at-rest condition should it be applied?
(OP)
Hi all,
I read on booke the at rest condition should be applied in case of deep foundations. When is a wall foundation considered deep? Is there any rule of thumb?
Thanks
I read on booke the at rest condition should be applied in case of deep foundations. When is a wall foundation considered deep? Is there any rule of thumb?
Thanks





RE: When the at-rest condition should it be applied?
As the movements are defined as a percentage of the wall height and the rotation would cause a large undesirable movement at the top of a tall structure, maybe that's why they recommend using at rest.
RE: When the at-rest condition should it be applied?
I know it, but how can I understand it? Is the allowable movement a kind of design constraint that it should be decided before the design?
RE: When the at-rest condition should it be applied?
Mike McCann, PE, SE (WA)
RE: When the at-rest condition should it be applied?
A basement wall, supported by the first floor, is restrained from moving and at rest pressures are applicable. But a cantilever retaining wall that can slide, deflect or rotate, would be subject to active soil pressures.
RE: When the at-rest condition should it be applied?
Pressures induced on a wall in an at-rest condition are often about 50% of the vertical effective stress. However active pressures are a lot less i.e. about 30% of the vertical effective stress. this means that earth pressures will be a lot bigger in an at-rest condition.
it is generally conservative to design a wall for at-rest conditions. I always suggest asking the structural engineer how much the wall can move before deciding what you are going to design for ka or k0.
Doug Hole
Junior Geotechnical Engineer
RE: When the at-rest condition should it be applied?
msquared48, where may I find some "threshold" values?
RE: When the at-rest condition should it be applied?
Take a look at pages 59-61 of NAVFAC 7.2
www.vulcanhammer.net/geotechnical/foundations.php
RE: When the at-rest condition should it be applied?