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Re: Completly shearing a building (also answer to perforatedshearwalls) -Reply

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David Puskas wrote:

** High Priority **

When it comes to single family residences it seems to me that we disregard the contribution of the plaster, stucco, drywall, drywall tape, ring shank nails, dry wall nails, paint, wall paper, shelving attached to the wall, electrical and plumbing conduit, etc, etc, etc, where they occur, when determining the stiffness of the structure to resist lateral loads.  It seems the way things are going we will have to build a full scale model to accurately determine which loads go where.  Not to metion the numerous deviations or conditions which normally occur during construction such as notched studs, relocated interior non-bearing walls, termite eaten framing members.  In my opinion the more we try to quantify everything the more we are tying our own hands (and fees).  How accurate do we really need to be when designing a building to protect the life and safety of the general public?  Are we to do an anlaysis everytime a minor element in the structure is changed, or take weekly site visits to input the contractors interpretation into our analysis everytime it deviates from our design assumptions?  What is he answer?

Dave Puskas
BSW International - Tulsa "The purpose of analysis is insight," and "an approximate answer to the right question is preferable to a very precise answer to the wrong question."  You all probably remember the humor in the cartoon depicting the different "solutions" to "What the User Wanted:  A Tire Swing!"

You bring up some interesting points.  New technologies are outstripping our traditional views rooted in conventional design and construction practices.  Yesterday I heard how a special "paint" was
used on the hull of the Delta Queen in the Mississippi to make it meet the fire resistance requirements and allow it to obtain a "permit" to carry passengers.  We already have "shearpaper" in the form of poly reinforced resins [FYBRWRAPS] being used to strengthen bridge piers, beams, parking structutres.  In Portland, a requirement that the "walls be attached to the roof" at the time of reroofing had to be abandoned in favor of by a "time certain" -- because "roof-technology-in-a-can" could extend some of these roofs indefinitely (2-3X longer than the Energizer Bunny!), postponing here-to-fore conventional reroofing operations.

One final point, if the new FEMA 273 -type existing building analysis techniques and following software can show that, because of all the factors you've listed, or because the contractor completely sheathed the building, the building "as constructed" was 1.2, 1.4, 3.6 .? ? ? times stronger than the
code "minimum" design requirement anyway, where does that leave us liability wise?

Maybe we could discuss a little more the different "insight" offered between some of these code design requirements that are a "plague on our House."

James Bela
Oregon Earthquake Awareness  /  The Quake Northwest
"We Have Nothing To Fear But Shear Itself"  /  "We're All Subducting In This Together"

PS:  I like the "duct tape".  According to the New Red Green Show, it'll fix anything!