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Re: Zone 4 Tilt-ups -- What to say to a Client

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Drew
I have seen high tech facilities, Fabrication facilities, upgraded based on
risk analysis to the client. Most fabrication facilities I worked on did
voulentary seismic upgrades since they cannot afford down time post seismic
event.  As a matter of fact, most people account for deisel generator
installation to run any where from 7 to 30 days assuming interruption in
the power grid or supply.  As far as codes requirements, it is very
difficult to retroactively justify retrofitting on existing building unless
the state or Jurisdiction like Los Angeles would render an order under a
building code ordinance to upgrade sub-standard buildings.
That's my 0.02 cents on the matter.
Hope that helps.
Samir Ghosn, P.E.
Harris & Associates

At 04:57 PM 10/10/2001 -0700, you wrote:
>Colleagues,
>
>Is there anyone out there in list-land who is on or familiar with the
>California Seismic Safety Commission and it's long-term plans in re
>tilt-ups?
>
>I have an architect/client with a business owner/customer who has retained
>them to make initial conceptual studies in regard to the construction of a
>high-tech fabrication facility at two alternative sites.  Both are in
>existing tilt-up concrete buildings constructed, "around 1970."  I do not at
>this point have documentation for either structure, but I know from limited
>field observations that both have wood ledgers.  The architect's preliminary
>assessment is that the proposed facility would be feasible (architecturally,
>mechanically, and etc.) in either building, with some preference for what I
>will refer to as Building B.
>
>My problem is that Building A (the less preferred alternate otherwise) may
>be the preferred alternate structurally.  It is in a city which has a
>retrofit ordinance and has had a structural upgrade to improve its ability
>to survive future earthquakes.  I know this because I was told
>(documentation for the retrofit is supposed to be available, but I have not
>yet seen it) and saw some of the retrofit ties during the initial site
>survey.  I saw nothing to indicate that Building B has had a similar
>retrofit.  The city in which it is located does NOT have a retrofit
>ordinance, and the building department says that it has at the moment no
>plans to adopt one.
>
>It is possible that Building B relies on cross grain bending for out of
>plane anchorage of some of its exterior wall panels (it is more likely that
>it has some out of plane anchors, but that they are grossly substandard with
>respect to post-Northridge code requirements).  The buildings are only a few
>miles apart, both in California, both in UBC Zone 4 and relatively near
>known active faults (subject to velocity and acceleration amplification
>factors under the 1997 UBC), which is the current model code in both cities.
>Neither show obvious external signs of existing earthquake damage or other
>structural problems.
>
>My general question is how to advise the client during this initial phase.
>His customer (the business owner) likes building B and is inclined not to
>worry about things that aren't going to cost him money right now.  If he
>goes with Building B, he may lease space or buy the whole thing.  If A, he
>will lease.  He is not likely to authorize the expense of document recovery,
>review and structural analysis to find out how bad the problems with
>Building B (or how good the retrofit at A) might be, he simply wants advice
>on feasibility based on the limited available information.
>
>Can anyone offer a clue of what might be coming down the pike in this regard
>(e.g. California Seismic Safety Commission requirements that could force the
>City where Building B resides to adopt a retrofit ordinance -- forcing the
>customer to pay for an upgrade a year or two down the road if he buys it
>now)?  I fear the owner may make a bad business decision, and want to make
>sure that I give the architect appropriate advice on the issue.
>
>Drew A. Norman, S.E.
>Drew A. Norman and Associates
>Consulting Structural Engineering
>Pasadena, California
>
>
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