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RE: RE: basement wall restrained by wood floor

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I agree, a tank approach can be used.  Usually, tanks have a bottom that are
integral with the walls (i.e., not an interior slab resting on subgrade)thus
picking up some "cantilever action".  I also agree that corners require
consideration due to the tension loading that the outside corner of the wall
will experience; I would hope that a PE would realize that this needs to be
looked into.  

However, if you have a 40' x 80' length of wall and down the length (with no
butresses) and you don't want to count on any restraint at the top, a
cantilever approach is fine for the majority of length of the wall.
Designing the majority of the wall as a cantilever or, designing the wall to
span horizontally between butresses, can be used. 

I agree that the cantilever approach may not be most economical or the best
design, but I would have to disagree with you that it is "not correct".

-----Original Message-----
From: David Hall [mailto:Dahl(--nospam--at)]
Sent: Wednesday, August 25, 1999 12:41 PM
To: seaint(--nospam--at)
Subject: Re: RE: basement wall restrained by wood floor

Basements are like tanks.  Designing basements as free standing cantilevered
walls may be considered conservative but is not correct.  Particularly
around corners.  You also will end up not designing many basements.

When I practiced in Denver, we designed many basements in expansive soil
situations and we used to add counter forts or buttresses at about 24 foot
centers to stabilize the walls.  Also, basements are really not much
different that tilt-ups or block buildings with wood diaphragms.  If one was
to design these floors as they would roofs for tilt-ups, consider installing
counter forts, and to install a perimeter drain system with a sump pump
system you should get good results.

David A. Hall, S.E., P.E.
Senior Structural Engineer
David Evans and Associates, Inc.
2828 SW Corbett Ave
Portland, OR 97201
Fax 503-223-2701
E-Mail dahl(--nospam--at)