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Re: Hardy Frame Panel PFC #5342

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There is not an ICBO approved cyclical test protocol for 
solid metal panels. To my knowledge, the only ICBO 
approved cyclic procedures are found in Acceptance 
Criteria AC130 (for prefabricated wood shear panels) and 
AC154 (metal sheathed walls attached with fasteners to 
steel framing) which both consider the importance and 
significance of ductility and energy dissipation.

Although the Hardy report refers to testing, since there 
is no ICBO approved AC or test protocol for metal panels 
there isn?t any way to load rate the panels based on 
testing. ICBO staff can verify for you that the 
allowable load values in the Hardy ICBO report end up 
being based solely on calculations.  

In performing calculations, the Hardy Frame braces do 
not meet the ordinary braced frame compression element 
width-thickness ratio as stated in 1997 UBC section 
2213.8.2.5 of 110/(Fy)^0.5 (3.5"/0.0747"=46.9 >> 110/
(50ksi)^0.5=15.6).  As mentioned previously, this 
section of the UBC is for structural steel and not for 
cold-formed steel; however, cold-formed should have even 
stricter requirements as it is more brittle than 
structural steel.  There are no Cold-Formed steel 
seismic provisions at this time.  Also analyzing the 
solid Hardy panels in a cold-formed program called CFSLT 
(available at http://www.rsgsoftware.com) as a "C-shape 
with stiffened flanges? cantilever member resulted in 
overstress when applying the allowable horizontal load 
shown in their ICBO report.

Intuitively, I would also expect the performance of wood 
shear wall to be quite different from a metal panel. 
Maybe not from the strength side but from the standpoint 
of failure mechanism & ductility.
> There is an applicable, ICBO approved,  cyclical test protocol and the 
> Hardy panel ER Report refers to cyclical test reports submitted. I would 
> expect that their performance was not that different from the Simpson 
> (and similar) panels and 4.4 is a reasonable value.  
> The R values in the code are related to the structural system's internal 
> damping and redundancy/reliability; but there is no rational, analytical 
> method for calculating R.  It looks to be a  seat-of-the-pants selection 
> made by some experienced engineers during the code process (somewhat 
> akin to laws and sausages).
> I'd be more confident about the performance of a 4' Hardy panel than a 
> typical 4' field constructed , 10d@ 2" o.c., OSB sheathed shearwall. 
>  However, that's just me. Feel free to assign any lower R value you feel 
> more comfortable with.
> Chuck Utzman,P.E.
> 
> 
> 
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