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RE: Washers for A325 Bolts

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This discussion reminds me of a situation that I heard of some time ago.
It appears that some tower companies are using A325 bolts with lock
washers.  Because of the competitive forces in the tower industry, the cost
of the kind of nuts and washers used 
sometimes determines who has the lowest price.  Some companies have been
using Anco nuts which are more expensive than the heavy hex nut.  Some
people are nervous about H.S. bolting with the special inspection
requirements when they see the special inspector using his binoculars to
watch the tensioning.

TIA/EIA-222 states that bearing type connections may be made with H.S.
bolts tightened to a snug-tight condition per the ASTM A325 specification,
but it doesn't change the type of washer.


Neil Moore, S.E.
Neil Moore and Associates
Consulting Structural Engineers


At 01:35 PM 10/16/2000 -0700, Bob Shaw wrote:
>No advantage. The friction between threads and washer/nut interface should
>be adequate to prevent  nut from loosening, even under vibration.
>SAE-published research backs this up.
>
>Introducing a non-ASTM, non-RCSC, non-AISC approved fastener element into
>the joint puts you into never-never land regarding following AISC and RCSC
>Specifications.
>
>Bob Shaw
>Steel Structures Technology Center
>www.steelstructures.com
>
>-----Original Message-----
>From: RainCat1(--nospam--at)aol.com [mailto:RainCat1(--nospam--at)aol.com]
>Sent: Monday, October 16, 2000 10:02 AM
>To: seaint(--nospam--at)seaint.org
>Subject: Washers for A325 Bolts
>
>
>AISC recommends ASTM F436 flat washers for A325 Bolts. Assuming the bolts
>are
>tightened by the turn-of-the-nut method, is there any advantage (or
>disadvantage) of providing lock washer after the flat washer?
>
>I thank you for your thoughts!
>
>Rainier C. Catubig, S.E.
>San Diego, California
>
>
>
>