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[SEAOC] Seismic Rehabilitation of Buildings

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Dear Colleagues,                                  December 3, 1996 
We are indeed fortunate that Franklin Lew, SE, Building Official for Contrat
Costa County, is willing and able to take the time to post messages on the
SEAOC List Server.
I agree completely with his  December 3, 1996 reply to Ali Sadre's December
3, 1996 criticism of FEMA 178.  Of particular importance from my point of
view is the statement "And engineers may find their legal counsels and E&O
insurance providers will be less than thrilled with multiple "standards of
care" associated with multiple levels of performance."

The following quotations from a forthcoming publication of the State of
California Seismic Safety Commission,  Products 1.2 and 1.3 of the
Proposition 122 Seismic Retrofit Practices Improvement Program, "Recommended
Methodology for Seismic Evaluation and Retrofit of Existing Concrete
Buildings" by Applied Technology Council, Richard W. Niewiarowski, Rutherford
& Chekene and Craig D. Comartin, principal authors, stand out in my mind to
support Franklin Lew's points of view in his reply to Ali Sadre's criticism
of FEMA 178 and his advocacy of "Vision 2000" and Seismic Performance Based
Engineering Guidelines for the design of new buildings and the evaluation and
guidelines for the rehabilitation of existing buildings.

1. Section 1.2.2,  Procedure for Evaluation and Retrofit Design.
" The owner's or building code official's selection of the performance
objective that should be achieved by a building retrofit is beyond the scope
of this document.  This includes the identification of the level of seismic
hazard that should be combined with the selected performance level.  Once
those decisions have been made, however, this methodology provides guidelines
to meet that objective.  Compliance with the procedure and requirements of
this document will be deemed adquate for these purposes, but, due to
significant variablility of expected ground motions and imperfect reliability
of in-situs materials, the seismic performance incoporated into the
performance objective is NOT GUARANTEED."   (Emphasis added.)

2,  Section 4.5.1.2, Earthquake Ground Motions Records.
"Figure 4-2 illustrates that predictions of response (and performance) using
smooth design spectra can significantly underpredict or overpredict response
(and performance) that the building actually experiences during the design
earthquake."

Reading of Products 1.2 and 1.3 is strongly recommended for architects, civil
and structural engineers, building code and regulatory enforcement officials,
building owners and managers, insurance industry representatives, material
interest representatives and others who are concerned about the seismic
design of new buildings and the seismic evaluation and rehabilitation -
retrofit - of existing buildings.  Contact Fred Turner, Structural Engineer,
 State of California Seismic Safety Commission, 1900 K Street, Suite 100,
Sacramento, CA 94814, Email address FredT5(--nospam--at)aol.com for publication date and
availability. 

Frank McClure    FEMCCLURE(--nospam--at)aol.com

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