Skidmore Verification of TC Bolts

[PT999]

TC Bolts - AISC RCSC Code and ICC Code requirements for Not Slip Critical
Do TC bolts that are not called on plans as "SC" have to be checked for tension calibration with a Wilhelm Skidmore.

The Code reads, "a tension calibrator shall be used where bolts are to be installed in pretensioned and slip-critical joints"

 

[JedClampett]

If TC stands for Tension Critical, which it might, why limit yourself to just a Skidmore device? There's torque wrenches (admittedly have to be calibrated) and several type of load indicating washers. Are these bolts already installed?

 

[azcats]

After reading a bit in the RCSC Specification, I say yes. The commentary in section 7.2 even references tension-control (TC) bolts.

Also, my understanding (RCSC section 9.3) is that the only difference between PT and SC, pre-installation verification, installation, and inspection requirements is that the faying surfaces meet the specified criteria.

 

[Ron]

A torque wrench should be calibrated to a Skidmore-Wilhelm tensioning device. As for the quality assurance if you are using load indicator bolts, it would be good to check a few with the Skidmore as well.

 

[HeavyCivil]

What Ron said. You use the skidmore to calibrate your torque wrench. If you have many of these connections I would encourage the contractor to use DTI's and you check them with feeler gauge.

 

[azcats]

TC bolts are the ones with the twist off spline that removes itself when the 'proper' torque is met. They are not tensioned with a torque wrench.

In theory, the fastener assembly should be tested in a skidmore to verify that it's producing the proper tension.

I think a strict reading of the RCSC document would even say that assemblies utilizing DTI washers need to be calibrated via skidmore to verify they're producing the desired tension.

IMO, the way the code reads does not limit skidmore calibration to torque wrenches only.