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Re: re/ Fp Values

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Whoever is going to answer this question, what about the extra connection
force at roof level due to the extra lateral force given the cantilever
parapet of this same tilt-up wall: 

Is the additional lateral load on the parapet, just because it is a parapet,
used in lieu of the force it would have been assigned the wall at that roof
diaphragm level, and if so, is the wall's anchorage design load increased
accordingly, as rational use of principles of mechanics would indicate? 

And is the parapet's cantilever moment effect at the next level down, which
acts opposite to the wall's local tributary connector design load, properly
subtractive from that connector design load down there?

May the negative cantilever parapet moment be used to reduce the positive
moment in the wall between diaphragm levels below? If so, is this parapet
negative moment taken as the special large one, or a lesser one based on the
Fp value for the wall that this thread seeks to clarify, or yet something
else?  

Lastly, from what established authority's chapter and verse do the answers
find support?

Charles O. Greenlaw SE   Sacramento CA

>Rick,
>
>Many people have been stumbling over the right seismic force to use for a
>building component that spans between elevations.  The 1997 UBC is unclear,
>in this case, about the proper definition of h sub x.  Outside of the Blue
>Book commentary, there have been recommendations that a trapezoidal
>distribution or an average of the top and bottom values be used.  In
>researching this issue, I found that in the 1997 NEHRP provisions, the
>variable z (same as h sub x) is defined as the highest point of attachment. 
>
>My question is; should this be the correct interpretation?  And what about
>the 2 vs. 3 difference?
>
>The answer could significantly affect design of tilt up or CMU wall panels.
>
>TIA,
>
>Curt La Count
>Jacobs Engineering
>Portland, OR
>