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Posted by Dan Deckert on February 22, 2007, 11:55 pm
> In a previous post Dan Deckert wrote...
> > Everything will meet or exceed any codes. The owner is just looking for
> > alternatives to beat the costs of construction costs (read labor
costs)as in
> > standard framing. Basically speaking, everything will be be overbuilt.
It
> > comes from working for the federal govt. where he is employed. Like I
> > stated, he's looking for alternatives to the labor side. His stepson is
> > working for licensed contractors putting up wood framed houses/etc. (10
> > years) and has some idea of what's going on. But the owner is looking
for
> > ways to do different things to cut costs.
> >
> > I was just looking for opinions on the design change. Little did I
surmise
> > it would create so much controversy/recoil for what I considered a
simple
> > change.
> >
>
> Dan:
>
> When the proposed structure is outside the normal framing methods then it
> is bound to start a controversy. I understand the concept of trying to
> cut costs. I make my best attempt to save the owner the cost of my fee in
> the details of every design I do.
>
> I will repeat: a building with 16-foot high walls is anything but ordinary
> and should be engineered. There is no "build in excess of code" here,
> because the code does not directly address this type of building.
>
> Does this mean strap bracing or even using the steel siding for its shear
> value is out of the question? No, it doesn't. But, only an engineered
> design can answer these questions. And that's the point I want to make.
> Trying to save a couple thousand bucks in engineering fees is not the
> answer if the building is under-designed from the start.
>
> As for loads, minimum ground snow load per SEAW Snow load manual =
> somewhere between 45 psf and 80 psf depending on project location.
> Minimum wind load is based on 85 mph (3 second gust) per state building
> code. If the building is fully enclosed then the 10 psf minimum rule will
> probably govern. If the building is only partially enclosed, then the
> design gets more complicated. Seismic load will be minimal, but not non-
> existent. For a light structure such as that proposed, wind load will
> definitely govern.
>
> I recently designed a shop/garage building in the Quilcene area using
> embedded poles. Eave height was only 9 feet. The building was not,
> however, a conventional pole building since the contractor did not want to
> deal with the heavy bolted truss connections required because of the labor
> involved. The roof system was metal over a plywood diaphragm transferring
> loads to the end walls. The end walls were plywood sheathed with metal
> siding. The back wall was metal siding only because it was a long wall
> and the shear value of the siding was sufficient to act as a shear wall.
> Shear walls were attached to the poles via strut/plate at the bottom of
> the wall. Pole embedment carried the loads into the ground.
>
> The above example is intended to show that it is possible to design
> unconventionally framed structures to save labor, but they must be
> properly engineered.
>
> --
> Bob Morrison, PE, SE
> R L Morrison Engineering Co
> Structural & Civil Engineering
> Poulsbo WA
> bob at rlmorrisonengr dot com
The above example is intended to show that it is possible to design
unconventionally framed structures to save labor, but they must be
properly engineered.
Agreed and without dispute. In this particular case, the owner wanted to
explore different ideas/designs with respect to labor costs.
Relative to Bobk207's answer of;
Pretty hard to beat stick framing & wood sheathing for speed of
construction & minimal labor. Gun nails are faster than screws.
While the above is true, the owner has no desire to include
interior/exterior wood sheating. In addition, it's faster, and less
expensive, (material/labor) to build the walls on a slab and fasten diagonal
shear metal banding (interior/exterior?) with screws then to cut/install
diagonal 2x6 shear bracing into the walls.
There's no doubt in my mind a Licensed Engineer needs to look at this and
approve of it, for comfort of mind if nothing else. Irrespective of that, I
still have a need to know whether this would a viable alternative. In my
mind, I don't see the 1x4 proposal being as solid as stick framed with
exterior wood sheathing. To that degree, I wonder how much structural
integrity will be lost by using the 1x4's on the face of the studs, with
structural metal ribbed panels on those, as opposed to using OSB on the
studs. I can 'see' the metal panels being worth next to nothing (shear) as
they would depend on the 1x4 connections to the wall studs.
I have no idea where this will wind up, but if it gets wierd, out of scope
and approved, I'll definitly post some dwg's someplace for all to see.
Thnx to all for posts.......................
Dan
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