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RE: A490 Bolts and Correct Washers

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Title: RE: A490 Bolts and Correct Washers

>At first glance, I just figured the author was referring to a PRETENSIONED
>application.  I was feeling confident and called to help the author out.
>Once on the phone, he informed me that it
>was a SNUG-TIGHT connection.
>I immediately flipped through the RCSC manual, 1994 and 2000, for the
>correct washer for the application.  In '94, section 7.(c)(6), it does
>mention the word "tightened", I think that would imply PRETENSIONED???

That implication was not intended. The ambiguity that is occasionally found in previous editions of the RCSC Specification has been clarified in the 2000 version. We were painstakingly consistent (at least I hope we were) in using proper and consistent terminology throughout. No more use of ambiguous terms like tightened.

>In 2000, 6.1. refers to 6.1.2,  which allows for F436 washer OR 5/16"
>thick common plate washer.  Would this be installers choice and would
>that be a HARDENED plate washer???

Section 6.1.2 specifically applies to snug-tightened joints. It calls for a standard 5/32-in.-thick F436 washer or common plate washer to cover a slotted hole in an outer ply. I suspect the F436 option will be the most commonly used option. However, if a plate washer is used instead, hardening is not required. This means the surface of that plate washer may gall. But in the snug-tightened condition, we are only concerned that the plies be brought into firm contact (see RCSC definition of this term  in the 2000 RCSC Specification if interested).

>does the 2000 manual become retroactive for all current
>projects started before 2000?  What about field inspection on projects
>built and still not fully inspected before the 2000 manual, what manual

The specifications, codes and standards referenced in the contract documents would control. However, I would always make judicious use of a newer version of one of those specifications when it becomes available. Particularly in a case like this where it can help to soplve the problem.


P.S. You can download the RCSC Specification for free at