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FEMA 273

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I would like some input on those using FEMA 273 guidelines for seismic
analysis and retrofit of existing concrete structures.

I am searching for a guideline that is accurate in predicting  D/C
ratios, and guidelines as to what D/
C ratios are acceptable for minimal life-safety performance for
individual structural elements.

Could the following scenario happen using the FEMA 273 guidelines:

Consider an 8 story concrete shearwall building, with columns and beams
that are not a part of the shear resisting elements.  Design was done
using Static lateral analysis procedures in the mid 1980's using the
1982 UBC.
A Dynamic analysis on the concrete structure is done using FEMA 273
guidelines.  The results tell you that the building has a potential risk
for failure.

I guess the problem is that I really do not alwyas believe what the FEMA
273 guidelines are telling me.  The building is a shear wall building.
The building's primary mode period is small (around .3) and overall
deflections are small.  When you sit back and study the overall
building's structural system, you come to the conclusion that it will
suffer some damage in an earthquake, but should not fail..

The Owner is only concerned about the safety of the people in the
building during an earthquake.  The Owner is not concerned at all about
the possibility of the building being a complete loss after an
earthquake.  A retrofit could cost millions of dollars.  FEMA 273 tells
me we should recommend a retrofit.  But as I look at the building, I
just do not see it failing.  This kind of building does not have a
history of failing during earthquakes.  It is after all a shear wall
building.  It was designed in accordance with the 1982 UBC.  Sure, it
does not meet all of the current 1997 UBC requirements, but I just do
not believe it will fail to a point where the occupants will be in for
anything more than a "wild ride" in an earthquake.

Are there any others out there that have run across this situation?  If
you have, what have you done?  When faced with a FEMA standard that
tells you the building is a danger, do you dare stand up and take the
liability of saying that you think the FEMA 273 standards are in some
circumstances too conservative and do not reflect how the building will
actually perform in an earthquake?  By stating such a position, your
liability could be tremendous.  Or do you just play is safe and have the
Owner spend millions on a retrofit, even though in your heart you do not
believe it is necessary.

This is my moral dilemma of the day.  Any insight would be appreciated.

Lynn