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[SEAOC] Re: [SEAOC] Plywood Shear Walls on Metal Studs and lightweight metal roof trusses

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To learn about  lightweight metal roof trusses, contact MiTek Industries Inc
(800)325-8075.  They have conducted the needed tests.  Unfortunately, I do
not think standards are available.
Frank Woeste,Professor of Wood Construction & Engineering

At 03:33 PM 8/8/96 -0700, you wrote:
>I previously reported that a SEAOSC Ad-Hoc committee was issuing a draft
>for cyclic testing of metal stud walls. This was not quite correct. I
>received a copy of the current draft this afternoon and provide the
>following Scope of work as noted on the report. Please note that this is a
>procedure only - for the cyclic testing of any framed wall system - not
>limited to wood and steel stud. The report is a current draft only. To
>obtain a copy, I suggest you contact SEA of Southern California and request
>the following title dated January 18, 1996 (11 pages total):
>
>
>"Standard Method of Cyclic (Reversed) Load Test for Shear Resistance of
>Framed Walls for Buildings
>Based upon ASTM Standard E 564-76 (Reapproved 1984)
>
>1. Scope
>1.1 This method is designed to evaluate the shear stiffness and shear
>strength of a typical section of a framed wall system, including its shear
>connections and hold-down connectors, under cyclic (reversed) load
>conditions. 
>1.2 This method may involve hazardous materials, operations, and equipment.
>This method does not purport to address all of the safety problems
>associated with its use. It is the responsibility of whomever uses this
>standard to consult and establish appropriate safety and health practices
>and determine the applicability of regulatory limitations prior to use."
>
>Essentially, this is a proposal for establishing testing criteria for any
>framed shearwall system. Once established and accepted, this criteria can
>be used to obtain working stress values for various shearwall systems
>including steel stud and wood frame.
>
>What I interpret from this is that there is no conclusive standard for the
>evaluation of shear wall systems under cyclic (seismic) load. Although the
>values published by ICBO appear to be the most current allowable stress
>which we are allowed to use, these are applicable to wood framed systems
>only.
>
>Once the Ad-hoc committee report is approved, appropriate testing can be
>done by the AISI and other interested proprietary suppliers to determine
>allowable values for each system.
>
>Finally, it appears to me that there are really two choices at the present
>for the design of plywood shear panels on steel stud. That is:
>1. Use the values provided by APA under the research report #154 (John R.
>Tissell, Structural Panel Shear Walls, APA Tacoma Washington, May 1993) for
>wind governed loads only.
>2. Disallow the use of steel studs with plywood sheathing for designs
>governed by seismic. The steel stud system may be able to be designed as a
>braced framed system rather than accounting for the capacity of plywood and
>screws.
>3. Design for alternative shearwall elements.
>
>Does this sound reasonable, or is there any other information out there?
>
>Finally, are there any standards for the manufacturing of lightweight metal
>roof trusses to be used on steel stud walls. These would be trusses spaced
>at 24" on center. 
>
>You comments are greatly appreciated.
>Sincerely
>Dennis S. Wish PE
>
>...
>
>

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