Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Bolt retightening

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Being an O.. F..., I can say that A325 bolts were
available in 1965-66, but there was a lot of distrust
of these new fangled things.  What is "fangled"?
Gary

On 28 Sep 2005 at 9:32, Paul Ransom wrote:

> > From: Kevin Below <kevinbelow(--nospam--at)videotron.ca>
> 
> > I am in need of some guidance on the right technique for
> > retightening bolts on a 40-year-old steel structure. One of my
> > clients, suspecting that the bolts in one of their many buildings
> > were loose, asked me to check.  Surprisingly, we found that his
> > suspicions were founded.  
> 
> That's really bizarre ... A client who knows enough to realize that he
> has loose nuts!
> 
> > My first question is whether I should require new bolts, since I
> > have no control or knowledge of the existing bolts.  It seems like a
> > good idea, especially if I need to calibrate the torque wrench.
> 
> Not certain about the bolt options from 1966. I sustpect that you
> could have A325. Check for marks on the head and nut.
> 
> > Also, the idea of a machine to calibrate the torque wrench each day
> > seems overkill to me, when this building doesn't seem to have
> > suffered in its loose state for so long, surviving mild earthquakes
> > and strong winds with no sign of distress, despite its lack of
> > tightened bracing. Would the turn of the nut be sufficient, or is
> > this really only for bearing type connections ?
> 
> Turn-of-Nut is the ONLY method that the CSA S16 recognizes for
> tightening for slip-critical connections. It is NOT required for
> bearing connections since they do not need to have the full tension in
> the bolt. Anything else is a method of confirming tightness (i.e.
> inspection). DTI washers are now explicilty acceptable for inspection,
> as well.
> 
> Even if you calibrate your wrench, you still have to achieve the
> Turn-of-Nut requirements and match mark the nut/bolt prior to
> impacting.
> 
> A325 bolts are considered to be reusable if you can run the nut for
> the full length of the thread with your fingers. There should not be
> visible damage to the shank.
> 
> -- 
> R. Paul Ransom, P. Eng.
> Civil/Structural/Project/International
> Burlington, Ontario, Canada
> <mailto:ado26(--nospam--at)hwcn.org> <http://www.hwcn.org/~ad026/civil.html>
> 
> ******* ****** ******* ******** ******* ******* ******* ***
> *   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
> * 
> *   This email was sent to you via Structural Engineers 
> *   Association of Southern California (SEAOSC) server. To 
> *   subscribe (no fee) or UnSubscribe, please go to:
> *
> *   http://www.seaint.org/sealist1.asp
> *
> *   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
> *   send to the list is public domain and may be re-posted 
> *   without your permission. Make sure you visit our web 
> *   site at: http://www.seaint.org 
> ******* ****** ****** ****** ******* ****** ****** ******** 



******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********