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Re[2]: Int'l Bldg. Code 2000 Seismic Maps

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Thank you Gary, I will order the 1997 HEHRP. I was not aware it was available 
yet. (Now if I can only find that FEMA phone #.)

Perhaps you could educate me a little on this.  In ASCE 7-95 Commentary, it 
says the Aa and Av contour maps are based on a 90% nonexceedence probability 
in 50 yrs (ie 10 % exceedence in 50 yrs.). Why the change to 2% ?

Also, can we now reasonably expect that ASCE 7 and BOCA and UBC will all 
refelect the earthquake provisions in IBC 2000 ? But come to think of it, I 
guess there will not be a BOCA and UBC when IBC 2000 is officially published, 
will there ?

Jim Fulton
______________________________ Reply Separator _________________________________
Subject: Re: Int'l Bldg. Code 2000 Seismic Maps
Author:  seaoc(--nospam--at) at Internet
Date:    3/6/98 9:02 AM

At 12:25 PM 3/6/98 -0500, you wrote:
>Recently, Roger Turk provided the USGS web site address where seismic maps 
>IBC 2000 could be found. Question: Which maps specifically are to be 
>? Are they the 0.2 sec and 1.0 sec Spectral Accel. with 10% Probability of 
>Exceedence in 50 years ? There are similar maps for other percent 
>of exceedence. 
>Jim Fulton
The IBC is based on the 1997 NEHRP provisions, which has established 
criteria based on 2% in 50 years.  However, a 2/3 factor is applied to the 
2%/50 spectral acceleration subsequently for design purposes.  You should 
obtain a copy of the 1997 NEHRP to review in detail  the design procedure, 
as there are many other differences.

Gary Chock

Martin, Bravo, & Chock, Inc.
1132 Bishop Street, Suite 1550
Honolulu, HI   96813
808-521-4513 (voice)
808-531-4508 (fax)

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Subject: Re: Int'l Bldg. Code 2000 Seismic Maps
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