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RE: DEFINITION: "Full-Factored Live Load

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I assume "full factored live load" to mean "all of it".  Wisconsin building
code allows you to use "...full load on any one portion of the roof are and
one-half on the remaining portion of the roof area...".  There are other
refinements for cantilevers.

The AISC (Section A4.1) says any probable arrangement of loads".  I asked
Charlie Carter about this once.  He said that AISC didn't make a more
specific requirement because "... given the wide variety of pattern loadings
specified by many model and local building codes..."


Roger Davis
SDS Architects, Inc
205 N. Dewey Street
Eau Claire, WI 54703
715-832-1605
rdavis(--nospam--at)sdsarch.com


-----Original Message-----
From:	Roger Turk [mailto:73527.1356(--nospam--at)compuserve.com]
Sent:	Monday, May 03, 1999 5:02 PM
To:	seaint(--nospam--at)seaint.org
Subject:	RE: DEFINITION: "Full-Factored Live Load

Bill,

It's true, factored unreduced live loads is not full-factored live loads,
but how can you get partial-factored live loads, or half-full-factored live
loads?

If you look at ACI 318-95, section 8.9.2, the hyphen is left out and this
section of the UBC is supposed to be identical to ACI except where
italicized.

Anyway, the way that I would read it would be as "factored unreduced live
loads."  (I debated whether to put a comma after "factored" and decided to
leave it out!)

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Bill Polhemus wrote:

. > But how is that "full-factored"? The hyphen is, I think, significant.

> -----Original Message-----
> From: Roger Turk [mailto:73527.1356(--nospam--at)compuserve.com]
> Sent: Monday, May 03, 1999 1:21 PM
> To: seaint(--nospam--at)seaint.org
> Subject: DEFINITION: "Full-Factored Live Load" in
>
>
> Bill,
>
> I would read this as you can't use the reduced live load
> (reduced based on
> tributary area).
>
> A. Roger Turk, P.E.(Structural)
> Tucson, Arizona
>
> Bill Polhemus wrote:
>
> . > Funny how your assumptions sometimes don't bear up when
> you actually
> . > scrutinize them.
>
> . > All along, I was assuming that live load "patterning" for
> analysis and
> . > design of R/C buildings included use of such patterning
> when lateral
> . > loading (such as wind) was part of the analysis.
>
> . > However, I'm unsure about what to make of the referenced
> paragraph.  For
> . > those without a UBC handy, I'll quote:
>
> . > "1908.9.2 It is permitted to [assume] that the
> arrangement of live load
> . > is limited to combinations of:
>
> . > 1. Factored dead load on all spans with FULL-FACTORED
> live load on two
> . > adjacent spans, and
> . > 2. Factored dead load on all spans with FULL-FACTORED
> live load on
> . > alternate spans."
>
> . > [Emphasis mine].
>
> . > Now that I read it, it seems to me that "full-factored" could be
> . > interpreted as meaning "the greatest-factored live load,"
> i.e. 1.4D +
> . > 1.7L, and that live load in all other combinations [e.g.
> 0.75 (1.4D +
> . > 1.7L + 1.7W)] need not be subjected to "patterning."
>
> . > Am I wrong? If so, how do you interpret this, and how do
> you accomplish it
> . > in your analysis?
>
> . > Thanks.
>