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RE: S.O.G. for resisting basement wall lateral force

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This is  an interesting conversation that will make me
think twice with tall basement walls.

One question - how is the slab prepared at the face of
the wall?  Is the common 1/2" filler negated to allow
the wall to push directly on the concrete?  Or is
there more of a hard connection that needs to be made
between the wall and the slab?

Jim Wilson
Stoudsburg, PA

--- "Haan, Scott M POA"
<Scott.M.Haan(--nospam--at)poa02.usace.army.mil> wrote:
> If you only have a coefficient of friction of .35
> you can end up needing a
> heavy building.  If there are a bunch of footings in
> a row I a guess you
> could use lateral bearing and use the struts/ribs
> between in both directions
> to try to grab the soil in lateral bearing.  It does
> not calc out well.  It
> does not work well for a building only buried on one
> or two sides.
> 
>  
> 
> 24' of burial can have a design reaction of
> 45*24*24/2*2/3=8640 lbs/ft at the
> bottom for at rest pressure or active+earthquake
> pressure.  For a coefficient
> of friction of .35 that would building weight of
> 24685 lbs/ft width to resist
> slab thrust not considering the basement wall
> reaction at the top of the wall
> and other lateral forces.  
> 
>  
> 
> ________________________________
> 
> From: Kestner, James W.
> [mailto:jkestner(--nospam--at)somervilleinc.com] 
> Sent: Wednesday, May 04, 2005 4:59 AM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: S.O.G. for resisting basement wall
> lateral force
> 
>  
> 
> Bruce:
> 
>  
> 
> If you have some heavily loaded interior footings
> with substantial dead load,
> you can run a compression strap to them from the
> outside wall footing. 
> 
>  
> 
> Jim K.
> 
>  
> 
>  
> 
>  
> 
>  From: Haan, Scott M POA
> [mailto:Scott.M.Haan(--nospam--at)poa02.usace.army.mil]
> Sent: Tuesday, May 03, 2005 5:10 PM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: S.O.G. for resisting basement wall
> lateral force
> 
> 	I was hoping someone else would respond, because
> this is a perplexing
> problem.  I have seen a bunch of people assume a
> slab on grade resists forces
> at the bottom of a basement wall and not many people
> design it.  I have had
> to look at a similar 24' tall situation.  It is
> going to need buttresses,
> dead men or a reinforced earth retaining wall behind
> the wall or something.
> 
> 	 
> 
> 	For a 8' floor to floor height no problem. For 20'
> retained height
> with a 45 psf at rest pressure how does it work
> [especially if the building
> is only buried on one or two sides]? 
> 20'*20'*45/2*2/3=9000 lb/ft at the slab
> on grade and another 4500 lb/ft at a restraint at
> the top of a wall.  For 4"
> 2500 psi concrete .85*2*sqrt(2500)*4"*12"/1.7=2400
> lb/ft allowable shear.
> Slab steel is going to be required for shear.  For
> friction to take out the
> lateral thrust at the base you need 13500/.35=38571
> lb of gravity load for
> friction for each foot of building width.  Each foot
> of building width would
> require a h=sqrt(13500/(.5*300))=9.5 ft high one
> foot width of lateral
> bearing.  This is in addition to the friction and
> lateral bearing resistance
> for lateral forces.   For tall buildings no problem
> but for a low light small
> foot print building  buried on only two sides not an
> easy solution?
> 
> 	 
> 
> 	For a slab on grade to work as a diaphragm you
> would need to have
> steel through control joints and dowel to side walls
> with no isolation joints
> and have enough friction from gravity loads and
> lateral bearing at interior
> footings and side walls for it to work.  If it is a
> vault kind of
> configuration, you could use wall formulas to check
> the slab on grade for
> compression between footings at opposite sides or to
> interior footings with
> enough friction and bearing.  If there is a vapor
> retarder under the slab it
> may be hard to get friction into soil underneath the
> slab on grade.  
> 
> 	 
> 
> 	 
> 
> 	 
> 
> 	
> ________________________________
> 
> 
> 	From: Bruce Holcomb [mailto:bholcomb(--nospam--at)brpae.com] 
> 	Sent: Tuesday, May 03, 2005 1:03 PM
> 	To: seaint(--nospam--at)seaint.org
> 	Subject: RE: S.O.G. for resisting basement wall
> lateral force
> 
> 	 
> 
> 	In this particular case, it is 20'-0" tall.  But I
> am interested in
> 'how' to analyze the slab-on-grade to resist the
> lateral earth pressure so I
> can use for other walls on future projects.
> 
> 	 
> 
> 	 
> 
> 	BDH
> 
> 	 
> 
> 	-----Original Message-----
> 	From: ASLCSE(--nospam--at)aol.com [mailto:ASLCSE(--nospam--at)aol.com] 
> 	Sent: Tuesday, May 03, 2005 3:35 PM
> 	To: seaint(--nospam--at)seaint.org
> 	Subject: Re: S.O.G. for resisting basement wall
> lateral force
> 
> 	 
> 
> 	How tall is the wall?
> 
> 

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