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Design Professionals in Steel Construction:
According to AISC specifications, all torque verified bolts are to be
checked with a torque wrench calibrated on a Skidmore-Wilhelm at least once
for each shift of work.
Our office has two such machines and we use them constantly, but the truth
is that very seldom is this requirement met.
The bolt is supposed to be tensioned in the Skidmore and the torque checked
and established at that tension for that shift of work.
In most cases, however, the bolt is torqued using a torque table and
depending on the coefficient of friction this torque can easily overload or
underload the bolt by as much as 40%.
A bolt overtensioned by 40% is seriously damaged....a bolt undertensioned
by 40% has significantly less value.
The specifications call for the Skidmore, but perhaps you in the design
world can give a hand by specifically  stating that this specification be
met and require bolt tensioning with a tensioning device (Skidmore) which
is then used to establish torque settings for the actual tightness
I've spoken with Henry Huang of LA County regarding this issue.  He is a
very knowledgeable and concerned Engineer who is trying very hard to bring
some serious issue to light regarding steel properties and mill certs we in
the Inspection world are being forced to buy off on.
Hey Henry, let's get some action going with the people on this list...over
2,000 strong and most of them, I believe, are Design Engineers.

R. Sandy Pringle			            Sandy Pringle & Associates
sandyp(--nospam--at) 		            STRUCTURAL INSPECTION CONSULTANTS   (800)598-1970    Fax(310)376-5294

		       		             Hermosa Beach & Redondo Beach, CA		

	Be the master of your will and the slave of your conscience.

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Richard Lewis, P.E.
Missionary TECH Team

The service mission like-minded Christian organizations
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