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Proofreading • Clarity • "Perforated Shear Walls" • Paris Airport Terminal Collapse

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In a message dated 3/9/05 3:50:47 PM, bill(--nospam--at) writes:
Probably these are typos.
"AS88" is most likely ASTM A588 "Standard Specification for
High-Strength Low-Alloy Structural Steel with 50 ksi [345 MPa] Minimum
Yield Point to 4-in. [100-mm] Thick."
And I would assume the latter means "ASTM A 36."

Good detective work, Bill.  This brings up a point (or four) that I've been thinking more and more frequently lately as I read the messages on this list:

1.  Couldn't we maybe do a quick proofread of our messages before we push the "send" button, so that they're more likely to say what we intend?  I know we're all short of time, but a moment spent by the sender might save hundreds of moments by the readers, and elicit more and perhaps more useful responses.  Some messages seem to be stream of consciousness straight to the Internet. 

2.  Please remember that the more information we provide when asking for assistance, the more likely that we'll receive useful responses.  Some of the recent requests have been of the "I'm designing a building; can anyone help me?" sort of thing.  How about a little bit of information about general location (you don't have to reveal the city, just the state, or even the country if it's smallish--to set the stage), the building material (makes quite a difference), the height ("multistory" covers everything from two-story to the Petronas Towers), and especially (for my way of thinking) the seismic area or lack thereof, or other special loading conditions.  Thanks!

This is not intended to insult anyone at all, just to make a couple of suggestions for better use of this list. 

A little personal opinion:  Do we really believe that "perforated (plywood) shear walls" will perform as well as what I would call "REAL shear walls" when push comes to shove, say a 7.0 on the Hayward Fault?  (That refers to a major earthquake near San Francisco, for those out of the area.)  I find it difficult to believe that we'll get much out of a shear wall without intermediate hold-downs with a full-size door opening in the middle of it, in spite of all the testing that's been done.  I suspect we're cutting all of the "fat" out of our shear walls, leaving not a bit of "excess" capacity that has helped our shear walls perform well in the past.  I can see us eventually believing that a house with one hold-down at each of the 4 corners is "adequate."  Cheap, yes, but adequate?? 

By the way, as I ramble on, is anyone else following the investigation of the fatal partial collapse of part of the one-year-old Paris airport terminal?  Scary.  Contractor-design.  Little verification of a very unusual and complex structural design.  Inadequate evaluation of temperature stresses. 

I probably should have chopped this into little pieces, but it's done now, so I'll send it ...


Ralph Hueston Kratz
Structural Engineer

Fax 510-215-2430

724 McLaughlin Street
Richmond CA 94805-1402 USA