Cob: FW: Steel Frame?

[j. gann]

Why ??
  Because cob is not available as a legal, affordable,
method. I for one , have too look at hybrids to make
it a reality, but am open to suggestions.
 We have spoken on this before. If one is a movie star
or has lots of money then one can afford an
"alternative/green home" with architects and engineers
.

But then I have been wrong before. What do you suggest
??



--- John Fordice <otherfish at attbi.com> wrote:
> Kristina and all,
> I assume cob as infill to a steel frame building
> would work.
> Until it was mentioned in this discussion,  I've not
> heard of anyone
> building with cob in this manner.
> 
> I'll pose the question to you:
> WHY ?
> What possess you to want to do this ?
> 
> Is economy  the issue ?
> Cob as a mass wall material is a lot of work & I
> wonder that adding
> steel  to it will just increase the cost where it
> really isn't needed.
> 
> Is it to build under an existing shelter ?  This
> does make a bit of
> sense, but tarps on poles are cheaper and unless
> you're building in
> hurricane conditions should work just fine.
> 
> It seems to me that introducing a steel frame into a
> cob structure
> pretty much negates the prime values of cob.
> 
> Some of the Prime Values of cob
> 
> Cob is simple.
> It allows freedom of form..
> Cob can be built using local  materials
> It is VERY sustainable. 
> It is low technology.
> Making and building with cob consumes very little
> energy.
> 
> How well does steel meet these Prime Values ?
> Steel in it's simplest and most economical form is
> the antithesis of cob.
> 
> Steel is recyclable (sustainable ? ), but only at a
> high environmental cost.
> Steel promotes rectilinear form./  
> To achieve freedom of form with steel is difficult.
> Steel in NOT local and involves distant resources
> and transportation in
> its manufacture and availability.
> Steel is technology intensive.
> Steel consumes lots of energy.
> 
> The value of steel is in it's strength, durability
> and ability to span
> long distances.  With steel you need relatively less
> material than other
> ways of building.   But if you really don't need the
> structural capacity
> of steel, why build with it ?
> 
> Properly designed cob walls can be built as load
> bearing and no
> additional structure is needed to support both the
> walls seismically and
> the roof.
> In fact, cob and other earthen materials actually
> perform better when
> they are load bearing.
> To build with cob as infill in a structural frame of
> some other material
> is to actually create a less safe structure.
> 
> If you really need to build a steel building with
> cob as infill, have at it.
> Just be aware that you are not using cob to it's
> full potential.
> Be sure that you tie any long straight sections of
> cob wall into the
> steel frame.  
> In seismic areas straight cob walls without
> out-of-plane buttressing and
> connection of the wall top to the roof diaphragm
> will be structurally compromised.
> 
> I wonder if anyone has studied the ductility of cob
> versus steel.  My
> guess is that steel is much more flexible (ductile)
> than cob.  If this
> is in fact the case, any steel frame acting as the
> structure both
> in-plane and out-of-plane will need to be braced
> sufficiently to react
> to seismic loads the same as the cob.  If not, there
> will most assuredly
> be failure points at any cob to steel interface.
> 
> This is an area rich for discussion and research,
> but be careful.  
> 
> john fordice
> 
> Kristina Buss wrote:
> > 
> > On Sat, 9 Mar 2002, Kristina Buss wrote:
> > 
> >  Anybody know if it is possible to do cob over a
> steel frame with the roof
> > already up? I know it is ok with post and beam but
> steel would be less
> > expensive, use recycled material, and have less
> waste. Anybody tried it?
> > 
> > Kristina
> >  kristinabuss at yahoo.com
> 


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