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# RE: 10/lw term in calculation of rho

• To: "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
• Subject: RE: 10/lw term in calculation of rho
• From: "Yousefi, Ben" <Ben.Yousefi(--nospam--at)ci.sj.ca.us>
• Date: Thu, 28 Oct 1999 12:21:43 -0700

```Frank

The following was the proposed wording suggested to be inserted after the
definition of r-max for all other walls:
"For wood structural panel shear walls, r-max shall be taken equal to the
shear in the most heavily loaded wall or wall pier multiplied by 4/lw
divided by the story shear where lw is the length of the wall in feet."

Another interesting fact is that, there was also a proposal to exempt the
horizontal diaphragms from application of Rho factor, which also made sense.
But that was unfortunately shut down. (The redundancy equations are based on
the distribution of loads to vertical lateral force resisting systems. Why
would we want to apply that factor to a horizontal diaphragm? )

-----Original Message-----
From:	FEMCCLURE(--nospam--at)aol.com [SMTP:FEMCCLURE(--nospam--at)aol.com]
Sent:	Thursday, October 28, 1999 2:16 AM
To:	Ben.Yousefi(--nospam--at)ci.sj.ca.us; seaint(--nospam--at)seaint.org
Cc:	FEMCCLURE(--nospam--at)aol.com
Subject:	Re: 10/lw term in calculation of rho

Ben Yousefi,

What was the exact wording of the two APA failed attempts to amend
the Rho
factor in 2000 IBC?

Have you reviewed the wording the 1999 SEAOC Blue Book, Section
105.1.1,
which states :  "The value of the ratio of 10/lw need not be taken
as greater
than 1.0"?  Would that wording help?

Frank E. McClure

```