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Re: Torque vs. Tension in Bolts

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At 10:20 PM 7/13/99 -0700, you wrote:

>My situation is for the use of expansion anchor bolts in concrete to
>connect a wood plate (sill or ledger).  The wood will crush before the
>required torque is achieved without a plate washer.  I want to determine
>just how big these plate washers need to be but need to convert torque
>value to do this.
-----------------------

This reply avoids both your question and the wood crushing problem.  If you
can use the "sleeve anchor" variety of expansion anchor bolt, rather than
the "wedge anchor" type, the nut and washer can be made to press on the
outer sleeve, which holds the expanding ferrule grip in place while the
tapered core is pulled upward inside the ferrule. This self-contained action
does not depend on the connected wood being loaded in cross-grain
compression at all.

Some models of sleeve anchor have a headed bolt within the outer sleeve,
instead of a male stud and nut. An advantage is that in event of removal
later, no stud or anything else projects above the concrete surface after
the bolt is unscrewed and loose outer sleeve lifted out. ITW Red Head
"Trubolt" is an example.

Charles O. Greenlaw  SE   Sacramento CA