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Cob: FW: Steel Frame?j. gann jmygann at yahoo.comWed Mar 13 15:52:27 CST 2002
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 > __________________________________________________ Do You Yahoo!? Try FREE Yahoo! Mail - the world's greatest free email! http://mail.yahoo.com/
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