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RE: Residential URM

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David,
First, you give me too much respect at the end of your e-mail. "Mr.
Wish" passed away in February of 2001 and I will always remain Dennis. 
I think the last three answers I've received is one of the reasons why I
am considering leaving engineering and opening a hot dog stand.

The addition added to this home was constructed in the 1950's and was
issued a permit for the work. The current work is being done by the new
owner and he is not removing any structural members other than some
ceiling joists that were damaged by a fire occurring before he purchased
the building.

Although I am familiar that residential (single and duplex) URM
structures are exempt from retrofit ordinances in most cities throughout
Southern California, I am pretty sure that this is the case in the
Inland Empire (San Bernardino County, Riverside and Imperial Counties)
due to the lack of money available in each of these jurisdictions to
mandate ordinances for retrofit of existing buildings until they are
remodeled or sold. In the Palm Springs area, there are many URM
buildings still remaining that are not retrofit, but which have been
reported to the state under the initial state requirement to identify
hazardous buildings.

The final say on the single family residence if an ordinance is not
established by the governing authority rests with the willingness of the
owner of the property once notified of the potential hazard to even a
single family structure. In this case, the new owner furred the URM
walls within the structure to allow for new electrical and plumbing. By
doing this, he has created a secondary support system at all bearing
walls to support the roof framing in the event the URM walls fail. If
anything, he has improved the structures without changing the loads
(both gravity and lateral) applied to the structure.

My initial question leads me back to the UCBC which I believe exempts
bearing wall buildings and single family residences - but I don't have a
current copy of the code and don't recall if this was changed. I do
understand that the CBC is the state's modified and adoption of the UCBC
and UBC (97) and wondered as well if this is indicated anywhere within
the adopted code.

David, I agree with you as I do the same. I have worked in a dangerous
building, but needed the job at the time. Since then, I make sure that I
properly document the choices for the client so that they will know what
to do or what their investment in voluntary compliance (or mandatory)
will be. I don't want to be in a position of not being explicitly clear
as to the risk of owning any building that is considered hazardous - and
I even include buildings I've inspected that are wood frame and
constructed by prescriptive methods. Although the code provides
documents to builders of prescriptive structures, my experience in the
area I live is that builders or developers don't read these documents
nor do they follow detailed guidelines. I am surprised that many of
these are inspected but not tagged. But as the building industry gets
busy, how close can an inspector work when he/she is given less than 10
minutes per building?

Thanks for the responses - I will follow through with each of your
advice and contact the local jurisdiction first - then base the limits
of my work upon their input.

Regards,
Dennis (AKA Mr. Wish)


-----Original Message-----
From: David Merrick [mailto:mrkgp(--nospam--at)winfirst.com] 
Sent: Sunday, April 13, 2003 1:19 PM
To: SEAINT
Subject: re: Residential URM




The structure does not require an upgrade if it is part of one of the
exemptions of CBC 3403.2. The URM ordinance lead to a dead end upgrade.
It does not allow the use of the upgraded URM materials for additions or
changes. Upgraded URM elements can remain if the 3403.2 exemptions
apply. Such as, the existing strength is not reduced, no additional
loads have been added, and the condition is not hazardous. The URM codes
can be considered the threshold for a hazardous condition.

Existing buildings can remain, as long as their capacity is greater than
a dangerous condition, and many times a complying existing structure is
less than current code. The URM code usually exempts a home from a
mandatory URM reinforcement but does that mean it is not a dangerous
condition?

"Dangerous" for structures is defined in the Abatement of Dangerous
Buildings Code as adopted by CBC. It has a rule that any measured stress
or requirement that is less than 66% of compliance of requirements for
new construction is dangerous and must be abated. One exception is San
Francisco, only a building official can deem a building, dangerous. Some
elements of the URM requirements appear to be less than 66% of code for
new buildings, but for lateral forces only.

Each jurisdiction adopts the URM ordinance with possible revisions. As
an example, the home exemption is one of the first paragraphs of the San
Francisco Code (16B, 1602B-Scope). The exemption of a home from the
mandatory URM upgrade, is probably an economical and political decision,
not because the URM is safe due to fact that it is a home.

I have been labeled a hypocrite because I walk into and inspect
dangerous buildings. I perform my committed duty. Daily, I do not live,
or work in dangerous buildings.

As for un-reinforced systems, you may have seen some of my inquiries
about using a Seismic R of 1.0 and what would omega be? The same goes
back to your inquiry of mammoth stone sculptures. All of these are
essentially un-reinforced as is not allowed by code, directly. Just how
is the rammed earth system per code? How are adobe buildings being
built?

This is for discussion only and hope to hear further responses to Mr.
Wish.

David Merrick, SE



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