Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: ACI 530-02/ASCE 5-02/TMS 402-02 Experts

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Thanks Scott.

Is there a specific commentary on section 6.2.2.3.1.5?

I guess I'm confused by the wording in the cited section 6.2.2.3. If the
presumption is that differential settlement is addressed with a "vertical
movement joint", then "where are the bodies?"

Also, you mention 12 feet as the maximum single story height considered
reasonable for fire safety. Does this imply 12 ft off the ground or 12 ft of
masonry height (at levels above 12 ft.)

I know Harold Sprague has suggested the arguments for this provision
(6.2.2.3.1.5) were born of considerations for a falling height of 12 or
greater, but I'm trying to be engineer here and do what is right for my
client without tripping over the code.

To help those who may be interested (or tired) in why I'm nit-picking, I
have a two story existing concrete home with a wood frame roof with
projecting eaves. The architect is proposing to add a limestone cornice
(veneer) wrapping the roof edge. This would be 20 or so feet above grade and
I've envisioned a double microlam fascia supported by microlam cantilever
beams. The members are significantly stronger than required by analysis and
the veneer attachments would be screwed to this backing. If fire is a
primary consideration, I could use triple members and perhaps achieve a
heavy timber rating. 

Any help in justifying or trashing this solution would be appreciated.

Barry H. Welliver
barrywelliver2(--nospam--at)earthlink.net
 

-----Original Message-----
From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu] 
Sent: Tuesday, August 31, 2004 9:49 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: ACI 530-02/ASCE 5-02/TMS 402-02 Experts

Barry:

Here is what the commentary of the 2002 MSJC says for section 6.2.2.3:

"Support of anchored veneer on wood is permitted in previous model
building codes.  The vertical movement joint between the veneer on
different supports reduces the possibility of cracking due to differential
settlement.  The height limit of 12 ft (3.7 m) was considered to be
maximum single story height and is considered to a reasonable fire safety
risk."

It would appear that some of the concern of supporting masonry on wood is
due to the combustible nature of the wood (but that may just be me reading
"between the lines").

HTH,

Scott
Adrian, MI

On Fri, 27 Aug 2004, Scott Maxwell wrote:

> --------------------------------------------------------------------------
> Your following message has been delivered to the list
>   seaint(--nospam--at)seaint.org at 17:59:21 on 27 Aug 2004.
> --------------------------------------------------------------------------
>
>
> Barry:
>
> Harold has already provided you with some good comments.  I will add to
> his comments that historically it was not permitted to support any masonry
> on wood construction with some very limited exceptions.  A good example is
> in the 1997 UBC (Chapter 21, I believe but don't remember for sure as I
> don't have it right in front of me).  I believe (going from memory here)
> that older versions of the MSJC (ACI 530, etc) had similar
> restrictions/limitations, but that changed in the 2002 MSJC.  As I am
> currently out of town, I don't have the 2002 MSJC in front of me at the
> moment, but I will endevour to remember to look at it when I get home and
> see if they have any relevant commentary for that section.
>
> Regards,
>
> Scott
> Adrian, MI
>
>
> On Fri, 27 Aug 2004, Barry H. Welliver wrote:
>
> > I'm just up from my nap.
> >
> > I appreciate your insight on this matter Harold. I was afraid there was
> > "thinking" along this line. By your comments, I presume there is little
> > explanation of this in the new commentary and applaud your intention to
> > follow through at your code development meeting.
> >
> > My own experience with code change proposals has reinforced the need for
> > good commentaries to help the users grasp a changed or new provision. I
also
> > realize how difficult writing those commentaries can be. Perhaps if the
> > proponents where required to provide verbiage for the associated
commentary
> > (to be published at the same time) the essence of the arguments would
also
> > have to be agreed to.
> >
> > I try to keep copies of the code change proposals specifically because
they
> > contain information about the logic of the proposition. I'm familiar
with
> > this in the IBC process. Is there a similar source for ACI/ASCE/TMS
> > approvals?
> >
> > Thanks again for being a well-spring of information for this listserv.
> >
> > Barry H. Welliver
> > barrywelliver2(--nospam--at)earthlink.net
> >
> >
> > -----Original Message-----
> > From: Harold Sprague [mailto:spraguehope(--nospam--at)hotmail.com]
> > Sent: Friday, August 27, 2004 12:05 PM
> > To: seaint(--nospam--at)seaint.org
> > Subject: RE: ACI 530-02/ASCE 5-02/TMS 402-02 Experts
> >
> > Barry,
> > I happened to be awake during the time that this was discussed in some
of my
> >
> > seismic code development participation.
> >
> > This was a reaction to a lobby by the residential building community.
Prior
> >
> > to this, it was prohibited to support ANY masonry from wood.  The
resulting
> > code was a compromise.  But masonry should not be supported by wood if
the
> > masonry is 12 ft from grade.  The argument presented at the time had
nothing
> >
> > to do with the weight supported by wood.  The argument presented was for
> > prohibition of a falling hazard.   I am sure that I could design wood to
> > support much more than what the code infers.  We have been remiss in
> > Commentary development.  I will make it a point to discuss this at our
next
> > code development meeting... right after my nap.
> >
> > Regards,
> > Harold Sprague
> >
> >
> >
> >
> >
> > >From: "Barry H. Welliver" <barrywelliver2(--nospam--at)earthlink.net>
> > >Reply-To: <seaint(--nospam--at)seaint.org>
> > >To: "Seaint Listserv" <seaint(--nospam--at)seaint.org>
> > >Subject: ACI 530-02/ASCE 5-02/TMS 402-02 Experts
> > >Date: Fri, 27 Aug 2004 09:54:06 -0600
> > >
> > >First of all I have to say keeping up with "code changes" is adding
grey
> > >hair on a daily basis now.
> > >
> > >
> > >
> > >An exception in section 6.2.2.3.1.5 allows support of masonry veneer on
> > >wood
> > >framing provided that the masonry has an installed weight of 40 psf or
less
> > >and height of no more than 12 ft.
> > >
> > >
> > >
> > >  My understanding of the 12 feet is a veneer weighing less that 40 psf
up
> > >to
> > >that height (i.e. 40 psf x 12 ft.) is the maximum load allowed for wood
> > >support. It has been suggested that this means masonry weighing 40 psf
> > >cannot be installed higher than 12 above the ground. If this (second
> > >suggestion) is correct, I'd like to know.
> > >
> > >
> > >
> > >Secondly, if this provision is intended to limit the weight of masonry
> > >being
> > >supported (and that's a big if), then would a single stone (such as a
> > >lintel, jamb or sill stone) which has a density exceeding 40 psf but
weighs
> > >significantly less than 40 psf x 12 feet, be "acceptable" as a rational
> > >interpretation (and hence be supportable on wood framing).
> > >
> > >
> > >
> > >Thanks for any help on understanding this "new" provision. As you might
> > >tell
> > >from my "inexperience" with ACI 530-02, I've yet to get this resource
and
> > >associated commentary.
> > >
> > >
> > >
> > >Barry H. Welliver
> > >
> > >barrywelliver2(--nospam--at)earthlink.net
> > >
> > >
> > >
> >
> > _________________________________________________________________
> > Check out Election 2004 for up-to-date election news, plus voter tools
and
> > more! http://special.msn.com/msn/election2004.armx
> >
> >
> > ******* ****** ******* ******** ******* ******* ******* ***
> > *   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
> > *
> > *   This email was sent to you via Structural Engineers
> > *   Association of Southern California (SEAOSC) server. To
> > *   subscribe (no fee) or UnSubscribe, please go to:
> > *
> > *   http://www.seaint.org/sealist1.asp
> > *
> > *   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
> > *   send to the list is public domain and may be re-posted
> > *   without your permission. Make sure you visit our web
> > *   site at: http://www.seaint.org
> > ******* ****** ****** ****** ******* ****** ****** ********
> >
> >
> >
> > ******* ****** ******* ******** ******* ******* ******* ***
> > *   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
> > *
> > *   This email was sent to you via Structural Engineers
> > *   Association of Southern California (SEAOSC) server. To
> > *   subscribe (no fee) or UnSubscribe, please go to:
> > *
> > *   http://www.seaint.org/sealist1.asp
> > *
> > *   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
> > *   send to the list is public domain and may be re-posted
> > *   without your permission. Make sure you visit our web
> > *   site at: http://www.seaint.org
> > ******* ****** ****** ****** ******* ****** ****** ********
> >
>
> ******* ****** ******* ******** ******* ******* ******* ***
> *   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
> *
> *   This email was sent to you via Structural Engineers
> *   Association of Southern California (SEAOSC) server. To
> *   subscribe (no fee) or UnSubscribe, please go to:
> *
> *   http://www.seaint.org/sealist1.asp
> *
> *   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
> *   send to the list is public domain and may be re-posted
> *   without your permission. Make sure you visit our web
> *   site at: http://www.seaint.org
> ******* ****** ****** ****** ******* ****** ****** ********
>

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ******** 



******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********