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RE: News from the IBC front

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Whoa! Forget IBC 2003 for a minute and let's talk about something a little
closer to my reach in my bookshelf, the 1997 UBC.

Am I missing something here? According to a conversation I had with Dick
Phillips at one of the SEAOSC seminars in the City of Commerce, it was NEVER
his intention for the 10/lw provision to be a penalty on short shear walls
but to be an aid on long shear walls.

So, with regards to the 1997 UBC, is it the intent of the code to use a
value of 10/lw greater than 1? If so, you are going to end up with a rho
greater than one on wood framed structures with multiple shear walls (albeit
short ones) which is rediculous and is contrary to the intent as I
understand it of the redundancy issue. This is because r-sub-max will be
based on a maximum value of f-sub-v and NOT the shear load in an individual
shear wall divided by the shear force at a particular level.

According to Dick Phillips, the purpose of the 10/lw feature was to
eliminate the penalty of long shear walls. Visualize a shopping center with
the rear wall being long and solid. The intent of this feature was to
consider this shear wall as individual walls 10 feet long.

Wasn't SEAOC going to write a white paper clarifying this issue?

Are building departments enforcing this issue? I haven't had any problem
with this issue in the projects I've submitted, but that really doesn't mean

Sheesh! I thought I had this damn thing figured out.


Bill Allen, S.E. (CA #2607)
Laguna Niguel, CA

||-----Original Message-----
||From: Yousefi, Ben [mailto:Ben.Yousefi(--nospam--at)]
||Sent: Tuesday, April 18, 2000 4:34 PM
||To: seaint(--nospam--at)
||Subject: News from the IBC front
||The ICC (International Code Council) recently finished the
||hearings for
||structural code changes proposed for the 2000 IBC. This is
||the first year of
||the 3-year cycle. All changes approved during the period of
||2000-2002 will
||get incorporated to the 2003 IBC.
||Anyway, one proposal, which might be of interest to some of
||you in seismic
||regions, was the redundancy coefficient for lightframed building. The
||proposed change would state that the value of 10/Lw need not
||be taken as
||greater than 1.0 for lightframed shear walls when calculating the r
||For more details on the proposals and results of the hearing
||check out
||Ben Yousefi, SE
||San Jose, CA