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Re: Hardy Frame Panel PFC #5342

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In response to my email request for test data, Hardy called today and offered to send me test data from the AC130 testing they have done. They tell me that the ICBO certification did not require (consider?) cyclical testing under AC 130 but COLA did. There is apparently a large amount of cyclical test data on Hardy panels. The fact that AC 130 is for wood sheathed walls is a lawyer's quibble, not an engineering evaluation. I do have some misgivings about the load cycles used in AC130, and I hear that the CUREE program has moved toward a more rational load cycle protocol. Regardless, Hardy has tested extensively to the best available, recognized shearwall test protocol and satisfied both ICBO's and LA's engineering staff's. With due respect to your intuition and FEA calculations, one test is worth a thousand expert opinions. If you are really interested in the facts, get the test data from Hardy. Neither the structure nor I really care if the diaphragm is metal or wood. After looking at a lot of poorly constructed, highly loaded shearwalls in my forensic work, I'm more confident about a factory fabricated/inspected shearwall--be it wood or metal. If you can show me a rational procedure that derives consistent R values from cycled load test data I would be impressed.
Chuck Utzman,P.E.
utej(--nospam--at)attbi.com wrote:

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.




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