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

RE: seismic isolation in wood framed structure

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Benjamin,

If there is not a change of occupancy that would increase the hazard posed
by the building because of a greater number of occupants, the objective in
relation to the stone walls will be to be sure that the addition to the
structure does not result in increase of design lateral load to the existing
stone walls.  I've accomplished this by adding lengths of reinforced
concrete or reinforced masonry shear walls positioned to intercept and brace
against increased lateral load to the existing unreinforced masonry walls
that would result because of the addition.  The reinforced concrete or
masonry walls need to be more rigid than the existing stone walls that they
are protecting from increased load, as well as satisfying the strength
requirements of the Code.  In general, this has meant that, while most of
the new walls and partitions may be wood framed, the lateral load resisting
walls for the addition will consist of a few carefully located and aligned
masonry or concrete walls.  In addition, you will need to provide
interconnection between the new and existing walls to assure that lateral
load is collected away from the old walls and delivered to the new.

If the project includes a change of occupancy, the Building Official
generally has the authority to require that the modified structure comply
with the modern building code.  I can't help if this is the case, but a
seismic separation may be unavoidable.

The International Existing Building Code, Appendix Chapter One, provides
prescriptive rules for evaluation and strengthening of buildings with
unreinforced masonry walls, including stone walls.  Many jurisdictions that
have adopted the IBC have not adopted the IEBC, but the Building Official
may allow its use, even for a change of occupancy

Nels Roselund, SE
South San Gabriel, CA
njineer(--nospam--at)att.net

-----Original Message-----
From: Benjamin Cornelius [mailto:bcorneli(--nospam--at)hotmail.com] 
Sent: Saturday, April 30, 2005 7:41 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: seismic isolation in wood framed structure

Yes.  They are unreinforced solid stone walls.  They are typically at the 
perimeter of the building and extend the full height from footing to eave or

gable.


>From: "Nels Roselund" <njineer(--nospam--at)att.net>
>Reply-To: <seaint(--nospam--at)seaint.org>
>To: <seaint(--nospam--at)seaint.org>
>Subject: RE: seismic isolation in wood framed structure
>Date: Sat, 30 Apr 2005 09:28:15 -0700
>
>Benjamin,
>
>What do you mean by rubble walls?  Are there stone walls in the old
>building?  If so, I've got some thoughts based on additions without
>isolation or seismic joints that I've designed for buildings with
>unreinforced masonry walls in Earthquake Country [CA].
>
>Nels Roselund, SE
>South San Gabriel, CA
>njineer(--nospam--at)att.net
>
>-----Original Message-----
>From: Benjamin Cornelius [mailto:bcorneli(--nospam--at)hotmail.com]
>Sent: Saturday, April 30, 2005 5:54 AM
>To: seaint(--nospam--at)seaint.org
>Subject: seismic isolation in wood framed structure
>
>Hi.  I'm designing a modest addition to a golf clubhouse, built as a large
>residence in NY around the turn of the century.  IBC 2003 says I must 
>either
>
>design the addition such that the entire structure conforms to the current
>seismic provisions, which is practically impossible given rambling nature
>of, and the rubble walls and wood framed construction in, the existing
>building; OR isolate the addition, which seems incongruous in a wood framed
>building in NY.  Any throughts would be much appreciated.
>
>
>
>******* ****** ******* ******** ******* ******* ******* ***
>*   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 
******* ****** ****** ****** ******* ****** ****** ********