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# Re: Seismic design of block fences

• To: seaint(--nospam--at)seaint.org
• Subject: Re: Seismic design of block fences
• From: Parkerres(--nospam--at)aol.com
• Date: Wed, 18 Aug 1999 01:08:28 EDT

```Harold and Bill -

Thanks for the site wall clarification.  We had been using hx = hr = 1
giving, F = .54 W based on ap=1, Rp=3, Ca=.44x1.3 and dividing it all by 1.4
for working stress.

At hx=0, eq 32-2 goes to Fworking = .14W.  This is less than eq 32-3 where
Fwrkg = .29W which is almost the same as the .30 W of the 1994 Code.

Unfortunately, we seem to have lost the 2/3 reduction for ground supported
walls that we used in the 1994 Code so F = .20 for site walls.  Where did it
go?  And why?

Bruce Resnick, SE
Parker Resnick Str. Eng.

In a message dated 8/17/99 1:49:26 PM Pacific Daylight Time,
harold.sprague(--nospam--at)neenan.com writes:

<< Currently you are in the right spot (32-2).  The h sub x and h sub r is
intended to reflect the effect of elevated floors for nonstructural
components.  The intent is that when you are on grade, the h sub x over h
sub r term goes to 0. >>

```