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Re: Is anyone interested? You Bet!

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Dennis Wish,

It is with my sincere thanks to you for your response to the subject email 
message that I reply to your always thoughtful and important comments.

Dennis, please I do not consider that you lost your temper and even raised 
your voice to me.  With all the information overload we all face each day we 
have to raise  the volume of  our voices sometimes to get other people's 
attention.

I agree with your statements concerning the cost of the time to travel, 
attending these seminars and agree that there must be a better way to provide 
access to the current and important information related to the practice of 
structural and earthquake engineering.  The unread technical journals, 
reports and books are piling up on my bed stand to the point that I wonder if 
I will ever catch up.

Concerning FEMA 273, without being too bold, it is my considered judgment 
that the authors of FEMA 273 might have gotten everything right, but the 
answer, when it comes to how to address overturning.  The fact that they have 
not been able to come forward and explain in simple rational engineering 
terms, using  the "First Principles of Mechanics (Statics), concerning how to 
address the large uplift forces that results from the application of the 
"Pseudo Lateral Loads" (FEMA 273, Equation  (3-6), page 3-7, V = 
C1*C2*C3*Sa*W to real buildings, and their last minute attempts to correct 
this problem with the "side-bar" equation, page 2-38, Section 2.11.4.1, 
Linear Procedure, Q = 0.9 QD + QE/ ROT, continue to raise my concerns. 

It is interesting to note that  the value of  ROT = 7.5 for Collapse 
Prevention (which has been increased to ROT = 10 in ASCE/FEMA 273) and the 
value of ROT = 6.0 for Life Safety (which has been increased to ROT = 8.0 in 
ASCE/FEMA 273) look very much like the much criticized R in the 1997 Uniform 
Building Code and 1997 NEHRP Provisions, and Rw in the 1994 Uniform Building 
Code.

John Kariotis in his review comments of the 75% Draft and Ballot Draft of 
FEMA 273 stated something to the effect that the basic research behind FEMA 
273 was flawed and was not applicable to real buildings.  The basic research 
was based, in part, on subjecting single degree of freedom computer models of 
buildings with varying fundamental periods of vibration to various ground 
motions.  By definition, single degree of freedom building models are fixed 
at the base of the building model in the supporting foundation material and 
therefore, by definition, do not have overturning problems. 

The fact that this condition of excessive overturning forces was not picked 
up in the  1997 BSSC "Validation of the Design and Analysis Procedures and 
Criteria In the 75% Complete Draft and the Ballot Draft in the Guidelines for 
the Seismic Rehabilitation of Buildings, FEMA 273" (I have looked at every 
page in this BSSC Report and not even one of the prototype building examples 
calculated the uplift forces at the bottom of the foundation and soil 
interface) leads one to the conclusion that the problem of excessive 
overturning forces was not considered in the final FEMA 273 (except to use 
large ROT values) leaving the continuing problem and the odd inconsistency in 
which the superstructure is not in equilibrium with the reduced foundation 
forces that result from the application of ROT.

Hopefully, the forthcoming BSSC Case Studies Project Report by Andrew 
Merovich will help answer and resolve some of the questions concerning the 
application of FEMA 273 to real buildings.  I am following very closely how 
the ASCE/FEMA 273 Project is attempting to address the excessive uplift and 
compressive foundation force problems that result from the application of 
very large equivalent "Pseudo Lateral Loads" (Base Shear Forces) that can be 
in excess of 1.0 gravity times the mass of the building.  It does not take a 
"rocket scientist" to realize that subjecting a real buildings to such 
excessive horizontal forces will result in overturning problems.

Dennis Wish, please keep your comments and concerns coming on the SEAINT 
about FEMA 273, FEMA 310 and ASCE/FEMA 273 even if you think you are raising 
your voice.  The issues related to these guidelines, prestandards and 
standards are too important to stand on protocol and nice manners.

Warmest personal regards,


Frank E. McClure      FEMCCLURE(--nospam--at)aol.com   June 7, 1999

File: denniswish4.doc