Check into ICC Code Clarifications for the 2000 IBC (on ICC website). I believe that there is a clarification that the safety factor of 1.5 for retaining walls does not apply to load combinations that include seismic. Although it applies to retaining walls, it provides evidence that a 1.5 safety factor with seismic is too conservative.
Bill Sherman
CH2M HILL / DEN
720-286-2792
From: Matthew [mailto:sandman21@gmail.com]
Sent: Thursday, January 31, 2008 11:30 AM
To: seaint@seaint.org
Subject: Re: Gross overturning
It is not the policy; the plan checker is insisting that it is common practice to use a 1.5 F.O.S. Every design professional, including himself, he was talked to uses 1.5 when using loads at ASD level. The shear walls range from 1.15-1.2, it would be extremely costly to get a 1.5 F.O.S. Can anyone offer advice on convincing him that he is wrong? :)
On Jan 31, 2008 10:16 AM, Steve Gordin <sgordin@sgeconsulting.com> wrote:
There is none. For seismic, everything about 1.0 is OK. I usually use not less than 1.2.It may be a city policy, then you are out of luck.V. Steve Gordin, SE
Irvine CA----- Original Message -----From: MatthewSent: Thursday, January 31, 2008 10:08Subject: Gross overturningI have a plan check comment stating that a 1.5 F.O.S. is required for gross overturning on any building shear wall from seismic loads at ASD level. The project is under the 97 UBC; I have been unable to find any code section that requires a 1.5 F.O.S, the only requirement is for earth retaining walls. Could anyone please comment on where I can find the section? Or how they have resolved a similar situation?Thank you