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Re: Thickened footings under interior braced walls (Was: RE Hardy Frames)

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Dennis,
 
You are 100% correct that engineers do not belong in the Conventional Construction. Many engineers do not know about it or do not want to learn about it. Then why it is still in the code?
 
I tend to think that it is the building officials --- almost all of them are non-engineers --- who have kept the Conventional Construction section of the code alive. ICC has given continuity and stength to it by publishing a separate code --- the International Residential Code (IRC).  If there were no such conventional thingy or IRC, there would be civil or structural engineers in place of these building officials in all the cities and counties; all my plans would be checked responsibly in-house; and the pain-in-the-butt/zero-responsibility/zero-liability outside plan checking agencies would not exist; and most importantly my cash-strapped city could keep the plan checking fees in its own coffers to repair the potholes in front of my house or keep my neighborhood fire station from shutting down rather than giving away almost all of it to those outside plan checking agencies.
 
Cheers,
Aleces
 
 
 
Dennis Wish wrote:
 
Most of us never put our noses where they don't belong and in my
opinion, engineers don't belong in Conventional Construction because we
can't make the numbers work. Conventional Construction, in its original
intention, was to replace log cabins when the first railroads were
constructed out west and saw mill equipment was shipped from the East to
the West.

To address the issues in your e-mail;
1. I see one area of argument. Section 2320.11.3 in the last paragraph
states; "....Sills shall be bolted to the foundation OR SLAB in
accordance with Section 1806.6."  I would interpret this (as would the
city inspector who does plan check for conventional construction)
connection to the foundation at the perimeter walls and the slab to be
used for braced wall panels on interior walls (or why even mention slab
unless intended to be used for a braced panel). Our building department
interprets this as differentiating between exterior foundation walls
(slab on grade) and interior slab thickness and is willing to let anchor
bolts extend into dirt. Their rationale is that pinning the sill to a
slab accomplishes the same thing as embedding it into the foundation -
it prevents the wall from sliding.

There must be something more definitive on this, but the trouble is
finding it.

(2) Section 2320.11.3 does set a minimum of 48" for wall panels up to
10' which would be a 2.5:1 ratio for shearwalls (or braced wall panels).
Section 2320.11 does not explicitly indicate a wall ratio other than it
does explain alternate braced panels in section 2320.11.4 and sets a
limit on these walls that can not be less than 2'-8" for limits up to
10-feet. For this condition, it sets a resistance to uplift at each end
of 1,800 pounds and then requires a tie-down device be installed for
this capacity. This increases if the alternate panel is on the first
floor of a two story building in which case the uplift is increased to
3,000 pounds.

So here is one question that confuses me: If a project is to be
prescriptively constructed, where is the span charts for beams and
headers over 8'-0" in width? How are the cities allowing more
complicated building designs to be done by conventional framing and not
providing span ratings for headers, beams and girders - who is to design
these? Even something so simple as a garage door header is not clearly
spelled out in the code and I don't find the section that says you must
use the 1-inch per foot rule for wood (16-ft opening therefore a 4x16 or
6x16 beam?

Dennis


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