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

RE: Adding a mezzanine to a Masonry Building in Seismic Zone 4

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Thank you Sid, this was exactly the information I needed. I do intend to
discuss it with the building department authority (who will probably be the
contract plan checker who generally calls ME to discuss similar issues). I
thin between the two of us, we should be able to come up with something
reasonable.
The only area of the building that, in my opinion, may be questioned for
upgrade, is not the area where the new mezzanine attaches, as from one of my
last posts, you will see that I am increasing the shear in the most critical
wall by close to 5% of the walls present demand. We are also infilling a
large opening which will add strength in the 8-inch masonry walls
(reinforced).
My concern here is the glass store-front and if the city or plan check
authority will require upgrade of the lateral system if this turns out to be
an open-front structure and second, upgrade of the existing lateral system
if it is designed to a lesser lateral load than current code dictates. Your
comments suggest that as long as I do provide less the original design, I
should be safe.

Thanks again for your evaluation of the code sections and you compliments. I
appreciate them a great deal.

Regards,
Dennis

> -----Original Message-----
> From: Sid Danandeh [mailto:sdanandeh(--nospam--at)cityofpalmdale.org]
> Sent: Thursday, May 17, 2001 11:46 AM
> To: 'seaint(--nospam--at)seaint.org'
> Subject: RE: Adding a mezzanine to a Masonry Building in Seismic Zone 4
>
>
> Hi Dennis
>
> I am glad that you are actively back in the list server , I consider your
> inputs/participation to be very valuable to the profession.
>
> Now as to this question:
>
> I suggest that you contact the AHJ . I.e. the authority having
> jurisdiction
> on this mater.
>
> No mater what other opinions may be the ultimate solution should
> match as to
> how it is handled at the AHJ. They are the one that will OK the plans.
>
> Now I also wish to point the exception to the section 3405. This exception
> grants the building official broad authority in determining weather or not
> the new or proposed use is less hazards than the existing use.
>
> Therefore except as provided in the exception to section 3405 , it is the
> intent of the code that a change of occupancy shall not be made unless the
> building is made to comply with the requirements of the code that are
> related to the proposed use.Thus structural requirements of the code must
> also be met where they are more restrictive for the new use.
>
> As the exception to section 3405 grants wide authority to the building
> official to use judgment in determining which code requirements will be
> exacted, the building official must be contacted in each case.
>
> When the Uniform code for building Conservation ( UCBC) has been adopted ,
> chapter 5 provide minimum requirements for a change in occupancy. If UCBC
> has not been adopted it dose provide provisions in chapter 5 to guide the
> building official in the promulgation of rules to enforce section 3405 of
> the UBC.
>
> The earlier codes required that the total building including existing
> building be brought up to the current code standards of the code if more
> than 50 percent of the value of the building was involved in addition or
> alteration or reconstruction.
>
> The basic requirement of section 3403.2 is that any structural alterations
> or repair made to existing building fully comply with all applicable
> provisions of the currently adopted code. Prior to the 1994 edition of the
> code there were no provisions to address voluntarily increasing
> the strength
> or stiffness of an existing building's lateral force resisting system. If
> such a work were to be undertaken , then full compliance with the current
> code would be required. An exception now permits such voluntary
> strengthening provided an engineering analysis is submitted to show
> compliance with the stated objectives. This exception permits existing
> structural elements to be altered and new structural elements to be
> installed for purpose of increasing the strength or stiffness of
> the lateral
> force resisting system.
>
> The exception specifies that the design force need not comply with the
> current code requirements .No force level is specified. However , the
> exception states that the capacity of existing structural
> elements required
> to resist forces may not be reduced ,thus , compliance with force at least
> equal to the original design force level seems to be implied.
>
> Before this exception was added , there was a distinctive for improving
> lateral force resisting elements because one had o either provide full
> compliance or do nothing.
>
> Improving the lateral force resisting capacity of a building's structural
> system can be extremely beneficial even when it is not possible
> to gain full
> compliance with the current code level. This should encourage rather than
> discourage strengthening. The exception states that work may be undertaken
> when not required by section 3401 .Since section 3401 dose not
> specifically
> address structural work, the intent of the reference is not clear. What is
> clear from the original proposal is that the exception was
> intended to apply
> only when voluntary strengthening of an existing building was proposed.
>
>  The exception should not be used as a reason for reducing force levels
> taken by existing lateral force resisting elements which will be used to
> brace an addition. Any addition plus existing building elements used to
> resist lateral forces generated by the addition should comply with the
> current code requirements.
>
> referring back to the exception in section 3405 , the building official is
> given broad authority in determining hazards involved in change of
> occupancy.
> In those cases the building official exercises the discretionary authority
> granted by the exceptions again AHJ should be contacted as to
> their specify
> jurisdictional interpretation.
>
> Sid Danandeh , PE(California), SE(Oregon)
> Senior Plan Check engineer
>
>
> -----Original Message-----
> From: Structuralist [mailto:dennis.wish(--nospam--at)gte.net]
> Sent: Wednesday, May 16, 2001 7:37 PM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: Adding a mezzanine to a Masonry Building in Seismic Zone 4
>
>
> Thanks Steve,
> It's good advice. Fortunately, my contract is with the tenant who
> is paying
> for the work. He has been informed that there are issues not yet
> resolved as
> to how much (or little) work is to be allowed by the city. I intended to
> call the city tomorrow and included one of the engineers who performs plan
> check services in the blind copy of my original post. The
> engineer is an old
> friend and would most likely be able to tell me what they will be looking
> for in upgrades on the building.
>
> Thanks again for your advice,
>
> Dennis
>
> > -----Original Message-----
> > From: Steve Privett [mailto:eqretrodr(--nospam--at)earthlink.net]
> > Sent: Wednesday, May 16, 2001 4:28 PM
> > To: seaint(--nospam--at)seaint.org
> > Subject: Re: Adding a mezzanine to a Masonry Building in Seismic Zone 4
> >
> >
> > I don't know about hardship, but I've had to do many seismic retrofits
> > as a result of occupancy change and been involved in even more projects
> > where my client went looking for another property because of the
> > required change.  While I know occupancy is usually the architect's
> > area, I recommend you be prudent and double check whatever the architect
> > tells you.  Have him give you code sections to justify a conclusion that
> > the occupancy is the same.  Architects do make mistakes and I didn't get
> > paid by an architect who made a mistake when he advised the client and
> > me.  The city read it as a change in occupancy, and the client went
> > elsewhere after we did the project.
> >
> > Steve Privett
> >
> > Structuralist wrote:
> >
> > > Sorry, I believe it was either a restaurant or a small bar
> > before. I don't
> > > think the occupancy changed, but I will ask the architect
> > involved as you
> > > raise a good point. However, is there no relief for tenant
> improvements
> > > where only one space is used. It seems somehow unfair to
> redesign an old
> > > building to accommodate a tenant change.
> > >
> > > Dennis
> >
> >
> >
> > *
> > *   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
>
>
> *
> *   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
>
> *
> *   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


* 
*   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