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RE: Structural Bolt Torquing Question

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If you are referring to the 2000 RCSC, Table 8.2 gives a rotation past
snug-tight, not a torque. The torque required to achieve the specified
turn will be variable, as you pointed out. There is a tolerance listed
in footnote a to adjust the required turn, if necessary, based on the
preinstallation verification tests. 

Calibrated wrench installation requires the preinstallation verification
testing to be performed daily for the calibration of each installation
wrench. Therefore, there is no specified torque. It is determined each
day, for each installation tool, on every combination of fastener
assembly diameter, length, grade and lot. The inspector is required to
observe this testing per the requirements of Section 9. So, it is left
up to the contractor, with inspector observation.

-Heath


> -----Original Message-----
> From: Eric Green [mailto:EGreen(--nospam--at)walterpmoore.com]
> Sent: Thursday, October 10, 2002 1:01 PM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: Structural Bolt Torquing Question
> 
> This is where the question came about. The specification gives torque
> information when using the turn of the nut method (Table 8.2), but
gives
> no information for torque when using torque control.
> 
> I realize the specification does state that the minimum tension should
> be equal to 70 percent of yield and I certainly understand how to
> calculate pre-stress from torque. I guess my question more accurately
> stated would be:
> 
> Who specifies K so that the relationship between torque and tension
can
> be determined? Surely one does not depend on the contractor for this
> information? Is it determined by the testing lab for each type of
bolt,
> nut and thread compound (if used)?
> 
> Eric Green
> - Fighting my ignorance since 1964.
> 
> -----Original Message-----
> From: LaCount, Curt [mailto:Curt.LaCount(--nospam--at)jacobs.com]
> Sent: Thursday, October 10, 2002 1:33 PM
> To: Seaint (E-mail)
> Subject: FW: Structural Bolt Torquing Question
> 
> Eric,
> 
> The answer is that nobody specifies torque.  The engineer should
however
> specify the tension by referencing the "Specification for Structural
> Joints Using ASTM A325 or A490 Bolts".  This is commonly done from the
> structural notes or in the specifications.  The installation is also
> subject to special inspection.
> 
> Curt La Count
> Jacobs Engineering
> Portland, OR
> 
> -----Original Message-----
> From: Eric Green [mailto:EGreen(--nospam--at)walterpmoore.com]
> Sent: Thursday, October 10, 2002 8:59 AM
> To: seaint(--nospam--at)seaint.org
> Subject: Structural Bolt Torquing Question
> 
> 
> 
> Excuse me for what is probably an obvious question for those of you
who
> deal with these connections on a regular basis:
> 
> Who normally specifies the required bolt torque for a slip-critical
> connection? The bolt supplier, steel fabricator or the engineer? Or is
> it some other party?
> 
> Eric Green
> - my ignorance is my own, not my employers.
> 
> 
> 
>
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