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Re: questions regarding transite roof decking

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I have a copy of an article by H. G. Allen titled "Tensile properties of
seven asbestos cements".  The article came from the June 1971 edition of
"Composites".  It contains the following information:

     Initial Young's modulus of composite varied from 8.45 to 20.41 GN/m^2.

     Ultimate tensile strength varied from 10.8 to 25.4 MN/m^2

     Strain at failure varied from 0.70 x 10^-3 to 5.06 x 10^-3

The variation appears to be mainly due to the type of fibers used and the
fiber content of the asbestos cement.





"Robert W. Williams" <robert.williams(--nospam--at)agra.com> on 02/29/2000 06:16:19 AM

Please respond to seaint(--nospam--at)seaint.org


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Subject:  questions regarding transite roof decking




        On a current project, a client has requested that I perform an
evaluation on an existing roof system for a primary freezer facility. The
roof which was constructed in the mid 1960s is comprised of 16" steel
joists spaced at 48" o.c. and corrugated asbestos-cement (transite) roof
decking. The transite deck has been filled with a lightweight concrete to
provide a level surface for the roof insulation. The client wants to put a
new roof on the freezer facility; however, they do not want

to remove the transite decking. The roofing contractor plans to strip the
roof of its existing components down to the concrete

leveling fill and install the new roof components. The new roof dead load
will be approximately 50% of that of the existing.

        With the new roof dead load being decreased, one should feel pretty
safe about leaving the transite deck in place; however, I am concerned
about the integrity of the transite panels. Based on a site visit, the
decking seems to be in good condition with no visible signs of flaking or
cracking. Based on a visual examination is it safe to assume that the deck
still possesses it strength characteristics.

        For the roof analysis I would like to run some quick deflection
numbers on the existing transite deck with the new roof dead load and live
loads as required by the current building code. Unfortunately, I know very
little about the material properties of transite. What is it's modulus of
elasticity.

        I have searched the company library and have not found any
information on the transite decking. For comparison purposes, it would like
to find some older vendor information on these transite deck panels (
section properties, load tables,

etc.). If anyone has any information on 3/8" thick decking with 3" deep
corrugations spaced at 4 1/2" center to center, I would greatly appreciate
it. My fax number is 404-370-3646. Any recomendations regarding regulations
or other concerns would also be helpful.

Thanks for the Help.
Rob Williams
AGRA Simons Atlanta
Associate Engineer, Structural
robert.williams(--nospam--at)agra.com
(404)370-3564