Return to index: [Subject] [Thread] [Date] [Author]

RE: Drift per 1997 UBC

[Subject Prev][Subject Next][Thread Prev][Thread Next]

I certainly did not mean to imply any impropriety by John Hooper. I know
john  Hooper and have a lot of respect for him. The reason I referred to him
is that his name had come up before regarding this issue. My personal
opinion is that he is may be pursuing this issue a bit too aggressively. But
that is certainly his prerogative.

John currently serves on the IBC structural committee, however, at the time
of 96 ICBO hearings for the 97 UBC, he was not a member of the ICBO code
committee, although I think he played an active role representing the
Washington SEA. I was on the committee in 96 and I can not recall this issue
being discussed with any specificity. However, of the last 6 to 7 hearings
that I have either sat on the committee or observed the process, I can not
recall any one more chaotic than that year.

The SEAOC seismology was determined to get the new provisions in the 97 UBC
since it was the last year of the code cycle and if they didn't, the next
opportunity would have been year 2000. Therefore, there were many caucuses
going to wee hours at night, and many revisions before or during the
meetings to reach consensus for the entire package to go through. It does
not surprise me if an item like this didn't get the proper attention that it

Ben Yousefi, SE
San Jose, CA

	-----Original Message-----
	From:	Gerard Madden [SMTP:GMadden(--nospam--at)]
	Sent:	Monday, February 05, 2001 9:55 AM
	To:	seaint(--nospam--at)
	Subject:	Re: Drift per 1997 UBC

	Thanks to all who responded, especially Martin & Mark who explained
the reasoning behind the difference in Zone 4.

	I hope I didn't sound like I was complaining about the provision. I
was simply asking why the difference was there from the previous code. I
also pointed out that if your structure is governed by eq. (30-7) for base
shear design (not just for drift design) and then you ignore the 1.3 Ta cap,
you are designing for a worse case than that for desiging frame elements
when checking drift because the higher the period, the more the vertical
distribution is thrown up toward the top level (i.e. - Ft gets bigger or
closer to the 0.25V limit).

	It seems that everyone is confused. Mark G. also stated that the
vote was not to use this equation but It never got into the code. I can't
see why it has taken more than 3 years to resolve when I believe there has
already been two erratta published from ICBO. I suspect that something else
is going on here.

	I had heard about the errata from others in my office, I knew it was
coming, and the name of Mr. Hooper came up as well. Is there some sort of
Conflict of Interest he may have here? I don't know who he is, but the last
post from Ben Y. stated that it came from his firm. Is he a code committe
member or something that makes Ben Y. imply some level of impropriety? Just
thinking outloud here ....

	Again, thanks to everyone and any updates you hear, I'd be
appreciate it if someone could post it for all to see.