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RE: IBC2003 for single family

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Jen – You are referring to 1614.1 exemption number 3 (my question is on exemption 2).  My understanding was that section 2308 was not to be used for “engineered” custom homes, mostly because architects don’t want all of the restrictions on their wall openings and such.  Looking more closely at exemption 2, it refers to section 101.2, which pretty clearly states…use the IRC!! 

 

So that brings up another question of circular code logic (of course)…being that section 101.2 is on the first page of the IBC, and it clearly says use the IRC for single family, why does IBC-1614 or 2308 even include references to single family homes in their verbiage?  An engineer shouldn’t need to go past page 1 in the IBC if they are working on single family residences.

 

So the heart of my question I suppose is this…can someone please clarify for me what guidelines the IRC provides for seismic design of residential structures? (I don’t have a copy yet).  Does is refer to ASCE 7?  Does it refer to the WFCM construction manual?  If it refers to ASCE 7-02, then section 9.1.2.1 exemption 2 mirrors my original question…Single family in A, B, or C does not need to be designed for seismic.

 

~~ Eli ~~

 

-----Original Message-----
From: Jen Wadsworth [mailto:JWadsworth(--nospam--at)TricoEngineering.com]
Sent: Thursday, August 05, 2004 12:09 PM
To: 'seaint(--nospam--at)seaint.org'
Subject: RE: IBC2003 for single family

 

Eli- It looks as though you need to read section 2308 carefully to see what it specifies for your structure.  I don’t think that section 1614.1 exception #2 relieves you from all seismic requirements – it simply says the structure isn’t required to be analyzed per section 1616.1. 

As far as the IRC goes, we use it for single family structures. Of course, for lateral analysis you’re referred to ASCE 7-98 and IBC2000

 

Jen

 

-----Original Message-----
From: Eli Grassley [mailto:elig(--nospam--at)psm-engineers.com]
Sent: Thursday, August 05, 2004 2:42 PM
To: seaint(--nospam--at)seaint.org
Subject: IBC2003 for single family

 

List:

We are taking the leap into IBC world up here in Washington, and I’m hashing through the lateral force provisions for design of an engineered single family home.  I’ve noticed a tasty exemption in IBC2003 section 1614.1, exemption 2…basically stating that single family light frame designs in seismic design category A, B or C are exempt from ALL of the earthquake design sections (i.e. just design for wind).  Is this wishful thinking, or am I missing something here? 

 

As a related question, has anyone delved into the IRC??  Does this code apply to engineered single family structures, or only to prescriptive design?  In other words, is the IRC only intended for architects and builders to use?  I have heard of a case where a structural engineer was sued because they used the prescriptive design procedures in their design of a wood framed house.  I guess the courts want to be sure us engineers actually use all those fancy buttons on our calculators.

 

Eli Grassley

PSM Engineers

Seattle