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Unblocked Plywood Diaphragm Deflection Calculation

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I am trying to compare the FEMA 273 equations for the deflection
computation of blocked and unblocked plywood diaphragm

The unblocked diaphragm stiffness is given by equation 8-5 with a G
(subscript: d) value of 800,000 or 400,000 (FEMA 273)
The blocked diaphragm stiffness is given by equation 8-6 & 8-7 (FEMA 273)

Using these equations will yield unblocked diaphragm stiffer than the
blocked one......

It appears that the equation 8-5 may be incomplete and missing the web
shear defection contribution.  Using ATC-7-1 one could compute unblocked
diaphragm stiffness which calcs out to be much less than FEMA 273.

Any comments, suggestions???


Niaz A. Nazir, PhD, PE