To: "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
Subject: RE: UBC Section 1612.2.1, Exception 2
From: "Haan, Scott M." <HaanSM(--nospam--at)ci.anchorage.ak.us>
Date: Wed, 28 Mar 2001 14:24:44 -0900
I have a course book that must be a later addition. It seems there was an
error in the 1997 UBC chapter 19 Div VIII section 1928 stuff. My course
Problem...Load factors of 1928.1.2 based on 1988 edition of ASCE 7 and do
not reflect earthquake load (E) at ultimate load level as adopted in
Solution...Use of load combinations in 1612.2.1 [Eqs (12-1) thru (12-6)
without the (1.1) multiplier] and set of strength reduction factors listed
in 1928.1.1 are compatible, without further modification."
I see designers use the UBC 1612 load combinations with the 1.1 factor for
seismic design all the time. The 1.1 factor is included in ACI 318-99
section 9.2.3 but then is not included in IBC 1605.2.1 which is referenced
in IBC concrete amendments.
Scott M Haan P.E.
Plan Review Engineer
Building Safety Division http://www.muni.org/building,
Development Services Department,
Municipality of Anchorage
phone: 907-343-8183 fax: 907-249-7399
> -----Original Message-----
> From: Bill Allen, S.E. [SMTP:Bill(--nospam--at)jrma.com]
> Sent: Wednesday, March 28, 2001 10:36 AM
> To: seaint(--nospam--at)seaint.org
> Subject: UBC Section 1612.2.1, Exception 2
> I have some hand written notes in my seminar book when I attended the ICBO
> Seminar on the 1997 UBC Earthquake Regulations. I believe the presenter
> S.K. Ghosh and I believe he said that this exception, which requires
> multiplying the load factors by 1.1, should be deleted and is not
> My questions:
> 1. Does anyone else have similar notes?
> 2. Has anything been published publicly (such as a SEAOC position paper)
> which states this?
> 3. (a big one), what about masonry?
> Bill Allen, S.E.