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Re: pointed stem wall under a PEMB?

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Coincidentally, the "alleged" building was somewhere
in northern New Jersey.

Jim

--- "Jordan Truesdell, PE"
<seaint1(--nospam--at)truesdellengineering.com> wrote:
> My thoughts are (1) knife points don't exist in
> concrete (2) a vertical 
> force on the sloped interior surface still has a
> vertical component and 
> (3) It's probably rare in modern times that
> significant frost 
> penetration would occur and cause damage.  IOW, I
> don't think its a good 
> detail, but it probably wont fail that often.
> 
> A better solution would be to excavate to frost
> depth and fill with a 
> porous material which is socked with geotextile, and
> make sure there is 
> a drain to daylight. from the bottom of the trench.
> Then thin your grade 
> beam to the structurally allowable minimum.
> 
> Jordan
> 
> Foy, Warren wrote:
> 
> >While I have not used such a detail, I have seen it
> in as-built drawings
> >for some buildings in New Jersey.  It was used for
> the bottom of a grade
> >beam spanning between pile caps so that the bottom
> of the grade beam was
> >not required to be below frost depth.
> >
> >-----Original Message-----
> >From: Jim Wilson [mailto:wilsonengineers(--nospam--at)yahoo.com]
> >Sent: Tuesday, April 26, 2005 10:16 PM
> >To: seaint(--nospam--at)seaint.org
> >Subject: pointed stem wall under a PEMB?
> >
> >
> >A contractor explained a detail to me today where
> the
> >perimeter stemwall of a PEMB building was shaped
> with
> >a pointed bottom at about 18" below grade in an
> area
> >with 36" frost depth.  There is no footing under
> the
> >stem.  The concept is that the frost heave will not
> >push on the pointed bottom.
> >
> >The steel frame still sits on concrete piers with
> >footings, hairpins, etc.  The stem won't be figured
> in
> >the structural load resisting system.
> >
> >This sounds a little bit clever, but I'm not
> >convinced.  He claims that he has used it before
> and
> >it has been accepted (by the building inspector,
> the
> >structural engineer, etc.)
> >
> >Is there such a detail and does it actually work? 
> I'm
> >suspicious, but who knows, maybe I learned
> something
> >today...
> >
> >Jim Wilson, PE
> >Stroudsburg, PA
> >  
> >
> 
> 
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