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RE: Roof Deck Personnel loading

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Stan,

It is possible to design for 20 psf live load and fail to provide
strength for personnel.

In the Vulcraft  catalog, a 1.5F, 22 gage deck (Intermediate Rib)  spans
7' and  supports 30 psf ( 10 dl + 20 ll).

In their specifications they note that for a 200 lb concentrated load on
the deck to provide a maximum of 4'-6" span.

My concern is that not all deck designs provide the table for
concentrated loads and therefore there are roofs in place that may be a
problem for personnel.


Ronald A. Hill, P.E.
HILL Consulting Engineering
PO BOX 26525
Birmingham, Alabama 35260 USA
Phone: 205-823-4784
FAX: 205-823-4145
email: ronhill(--nospam--at)hillce.com
http:\\www.hillce.com


-----Original Message-----
From: sscholl2(--nospam--at)juno.com [mailto:sscholl2(--nospam--at)juno.com] 
Sent: Friday, September 20, 2002 10:06 PM
To: seaint(--nospam--at)seaint.org
Cc: seaint(--nospam--at)seaint.org
Subject: Re: Roof Deck Personnel loading

It is perfectly safe to walk on a 20psf roof (which is what we have in
CA). It is not safe to send an army up there or to stack a lot of
material close together.

Stan Scholl, P.E.
Laguna Beach, CA

On Fri, 20 Sep 2002 12:01:47 -0500 "Ron Hill" <ronhill(--nospam--at)hillce.com>
writes:
> Roger,
> 
> You are Correct for uniform loading.  My question is how we tell an
> owner it is safe to walk on the roof.
> 
> Scenario 1:   An employee weighs 200 pounds and can easily stand 
> with in
> the 12" square tile on the office floor.  This computes as 200 psf.  
> The
> owner asks "It is safe to walk on a 30 psf roof????"
> 
> Scenario 2:  The metal roof deck spans 4 ' between the joists.  A - 
> 200
> pound man are standing on a bay 12" wide between the joists.  
> Another
> 200 pound man walks up and stands beside him to look at the AC unit.
> Their weight on the deck bay is now 400/1/4 = 100 psf.  The 
> combinations
> are endless.
> 
> I have not seen any information in SDI that can document that the
> loading is safe.
> 
> 
> 
> Ronald A. Hill, P.E.
> HILL Consulting Engineering
> PO BOX 26525
> Birmingham, Alabama 35260 USA
> Phone: 205-823-4784
> FAX: 205-823-4145
> email: ronhill(--nospam--at)hillce.com
> http:\\www.hillce.com
> 
> 
> -----Original Message-----
> From: Roger Turk [mailto:73527.1356(--nospam--at)compuserve.com] 
> Sent: Friday, September 20, 2002 10:29 AM
> To: seaint(--nospam--at)seaint.org
> Subject: Roof Deck Personnel loading
> 
> Ron,
> 
> I think that the 30 psf roof load relates more to stacking roofing
> materials 
> and the effect of snow than it does to personnel loading.
> 
> For personnel to come close to the 30 psf loading, you would have to
> have 180 
> pound people standing 2.5 feet apart over the entire considered 
> area.
> In 
> other words, it would be quite congested.
> 
> A. Roger Turk, P.E.(Structural)
> Tucson, Arizona
> 
> Ron Hill wrote:
> 
> . > I have a question about roof decks and 30 psf live loading.  I 
> have
> . > looked in the codes and in the manufacturers data concerning
> permissible
> . > personnel loading on roof decks and can not find anything. 
> 
> . > When we design a roof for a uniform live load of 30 psf, how 
> does
> that
> . > correlate to how many men can stand in one area on the roof at 
> any
> given
> . > time??
> 
> . > Ronald A. Hill, P.E.
> 
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