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RE: Yet another Wind question

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That's the way I read it too.  In fact it seams like you would never 
use the negative numbers in that table.  They could all be replaced 
with zeros.  Any situation/reason why not?


-----Original Message-----
The values in the tables in Figure 6-2 are negative in zones B and D for
lower slopes.  Rather than using the negative numbers you use 0 psf when
calculating the base shear.

-----Original Message-----
From: Mark Johnson [mailto:markajohn(--nospam--at)]
Sent: Tuesday, February 05, 2008 2:17 PM
To: seaint(--nospam--at)
Subject: Yet another Wind question

Here is yet another wind analysis question.
This is about MWFRS using the simplified method (Method 1) of ASCE7.
Footnote 7 of figure 6-2 (pg 37) says "The total horizontal load shall not
less than that determined by assuming ps = 0 in zones B & D."
I see that ps30 on areas B and D are horizontal pressures.  (vertical forces
on these surfaces are calculated as areas E, F, G, & H)
I can't think of a time when you would use a pressure (ps30) on areas
B & D that was less than zero and none of my new books deal with this.
What am I not thinking of?

Mark Johnson

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