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RE: Some of the Strangest Codes I've seen

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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. As 
> many of you know the new code restricts shearwalls so as not 
> to exceed a 2:1 
> 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 tolerance 
> of stiffness (deflection) as possible.

"As close as possible" is a terrible phrase to use if that's the language in
the code. Since anything is "possible", that means you (and the architect)
should do whatever it takes to make the stiffnesses identical!!  It's an
awful phrase to use!  
ICBO lost their nut when they did this code (IMHO).

> I received a call from a local designer this afternoon who 
> informed me that 
> he is designing a home by prescriptive methods which allow 
> all shear walls in 
> 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 in 
> the Conventional framing section of the code which was 
> intended to use at the 
> 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 engineer) 
> 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 2 
> 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 nailed 
> with 8d common or galvanized box nails in accordance with 
> Table 23-II-B-1 and 
> blocked at all plywood edges....."
> It seems that there are consequences which, in my opinion, 
> will degrade the 
> quality of construction by creating an incentive for the 
> developer to keep 
> his structure in strict compliance with Conventional Framing 
> practices so as 
> 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 must 
> be forced to place more money in their structures than they 
> have budgeted and 
> which will take away from their finishes. At the same time, 
> those who can not 
> afford a custom home will be forced to endure more damage since, by 
> comparison, the prescriptive appropach is so much less than a 
> minimum level 
> of code compliance.
> Dennis Wish PE