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Re: Some of the Strangest Codes I've seen

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You are quite right. I'm the Supervising Plans Examiner for Precision
Inspection Company and have very few dwelling come through as conventional
construction. Out of the last 250 plans checks, I would venture to say 5
dwelling actually complied with the conventional construction requirements
of UBC 2320.

Generally, the garage portal is ultizing the alternate brace wall panels and
at the front wall room projections (Living, Kitchen or Bedroom). The two
main problems I've seen that void the conventional construction requirements
are the girder truss (if used) supporting the main roof to the rear of the
garage. This condition must comply with UBC 2320.5.4.2, often a problem. The
second issue with the interior braced wall lines is the available interior
walls within a 4 foot offset to provide the required BWP's with teh required

Additionally, the anchor bolting per 2320.6 refers you to the bolts as
required in 1806.6. 1806.6 requires 1/2" or 5/8" AB's with minimum 7"
embedment, so on a single story slab dwelling with no interior footing, you
must now provide minimum 10" from finished floor to the bottom of the

Tom Liberty

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Subject: Some of the Strangest Codes I've seen

> As engineers are struggling to comply with the new 97 UBC code provisions
> there still remains a section of the code that mocks the entire process.
> many of you know the new code restricts shearwalls so as not to exceed a
> aspect ratio. On top of this, we are expected to consider the entire
> structure and balance the shearwalls so as to be within as close a
> of stiffness (deflection) as possible.
> I received a call from a local designer this afternoon who informed me
> he is designing a home by prescriptive methods which allow all shear walls
> a one story structure without irregularities to be design with a minimum
> 2'-8" wide x 10' tall panel. I reminded my friend that this provision was
> the Conventional framing section of the code which was intended to use at
> front of garages where the open restricted the size of the piers and where
> the risk to loss of life was less than that of the dwelling.
> He told me that he argued the point with the plan reviewer (not and
> who agreed that the way it is worded in the code, the designers of
> non-engineered prescriptive structures may use a 2'-8" X 10' tall panel in
> place of a 4x8 panel anywhere in a one story structure.
> The section 2320.11.4 states:
> "Any braced wall panel required by Section 2320.11.3 may be replaced by an
> alternate braced wall panel constructed in accordance with the following:
> 1. In one-story buildings, each panel shall have a lenth of not less than
> feet 8 inches and a height of not more than 10 feet. Each panel shall be
> sheathed on one face with 3/8-inch-minimum-thickness plywood sheathing
> with 8d common or galvanized box nails in accordance with Table 23-II-B-1
> blocked at all plywood edges....."
> It seems that there are consequences which, in my opinion, will degrade
> quality of construction by creating an incentive for the developer to keep
> his structure in strict compliance with Conventional Framing practices so
> to avoid comformance to an engineered solution whose minimum requirment is
> many levels higher than this section of the code implies.
> If we are forced to so dramatically restrict our design of wood structures
> with the new methodologies of the code, the least we should expect is for
> this section of the code to be rewritten to provide no less than an
> equivalent minimum standard of the engineered solution.
> My dilemma is that those who can afford compliance are angry that they
> be forced to place more money in their structures than they have budgeted
> which will take away from their finishes. At the same time, those who can
> afford a custom home will be forced to endure more damage since, by
> comparison, the prescriptive appropach is so much less than a minimum
> of code compliance.
> Dennis Wish PE