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RE: IBC 2000

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Allen Adams interpretation is consistent with what I understand the intent
of the current ASCE 7 to be. Transient loads are those that have a
significantly different arbitrary point in time value versus their maximum
lifetime value. In this respect, I think all loads other than dead load are
transient, including live loads, roof live load, wind loads and seismic
loads.

We will all have to update our understanding of the applicability of the 1/3
stress increase -- or the 3/4 load reduction factor as it is now prescribed
in ASCE 7. As I have posted in previous messages, this world has changed
underneath you.

Note that AISC has, of necessity, conformed to the requirements of the
current ASCE 7. This is formalized in AISC ASD Supplement No 1, which can be
downloaded for free from the AISC web site.    

Charlie


-----Original Message-----
From: Lutz, James [mailto:JLUTZ(--nospam--at)earthtech.com]
Sent: Thursday, October 03, 2002 10:39 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: IBC 2000


I've never heard this interpretation before. I thought only wind and seismic
were transient loads. See for example 1997 UBC 2209, where allowable stress
increases are only permitted for wind and seismic load combinations. I think
I will stick with this interpretation.

-----Original Message-----
From: Allen Adams [mailto:aadams(--nospam--at)ramint.com]
Sent: Thursday, October 03, 2002 8:23 AM
To: seaint(--nospam--at)seaint.org
Subject: FW: IBC 2000


"Transient" loads are any non-permanent loads (Wind, Seismic, Live, Roof,
but not Dead Load). This means, for example, that the Load Combination
given by Formula 16-9 of Section 1605.3.1 becomes:

   D + 0.75L + 0.75(Lr or S or R)

but if there is no Roof Load it is

   D + L

or if there is no Live Load it is

   D + (Lr or S or R).

You have to check all three combinations.

The 0.75 factor can only be used if there are multiple transient loads
simultaneously applied. It is to account for the lower probability that the
peak values of those loads will occur simultaneously.
Allen Adams, S.E.
RAM International



 -----Original Message-----
From: 	Jim Kestner [mailto:jkestner(--nospam--at)somervilleinc.com]
Sent:	Wednesday, October 02, 2002 9:47 AM
To:	'SEAINT'
Subject:	IBC 2000

Section 1605.3.1.1 Load reduction allows a reduction of the combined effect
of two or more transient loads. ASCE 7-98 omits the word "transient".

Does "transient" mean short term load such as Wind and Earthquake only or
does is it meant to include various forms of Live Load also?

I cannot find any definition of "transient" in the code.


Jim K.



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