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[SEAOC] Re: [SEAOC] Re: [SEAOC] Fwd: Conventional construction provisions

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At 11:02 AM 5/23/96 -0700, Wish wrote:
>BTW, in addition to my comments to Ray's message I would like to add one 
>or two observations from the damage that I inspected from Northridge.
>1. One home in Woodland Hills appeared to be constructed according to an 
>engineered set of plans. This was evident from the use of very heavily 
>sheathed interior shear walls. The one interior wall I inspected was 
>sheathed both sides with 15/32" Structural II plywood and nailed with 
>10d nailing at 4:4:12. Simpson HD15's (or possibly 20's) where attached 
>at each end and anchor bolts where assumed sufficient since the wall was 
>not open to inspection. The wall was set on a foundation that was at 
>least three feet wide, but could not be verified by sight for depth.
>The kicker was that the top plate of the wall was nailed to the ceiling 
>rafters and this is where it stopped. There way about three feet of 
>space between the top of this wall and the roof diaphragm. 
>The location of the wall suggests that it was designed for about 50% of 
>the tributary shear, but since it wasn't connected to the roof (and 
>assuming that a gypsum ceiling was not used to transfer shear from the 
>another portion of diaphragm down to the wall) it was useless. 
>Structural Observation requriments may have prevented this from 
>happening. If this contractor/framer did not understand how to connect a 
>shear wall, how would a simple framer who builds under conventional 
>framing requirments know the engineering principles for shear transfer?
>2. How many hundreds of stucco failures occured? How much damage was 
>caused from plywood shear wall deflections exceeding code story drift of 
>0.005h? Too much from what I saw. 
>Finally, how can ICBO publish codes to allow non-professional to 
>construct even low risk structures when the engineering community can't 
>enforce even decent construction practice?
>One problem is the engineers will not get off their asses and go to the
jobsite. After one visit they want to start charging fees. This doesn't get
it. I have never seen a set of plans or a building that was free from errors
and omissions, or that did not need changes. Just trying to get the
"professionals" to give us a stamped drawing takes Herculean efforts.
Structural observation is a joke.

David Owens
Senior Construction Inspector, City of Los Angeles