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Checking bolt torque in freezing condition

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Navid.Nik

Structural
Joined
Nov 25, 2020
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18
Location
NL
I have a question regarding the bolt tightening in the freezing condition. The connections are not slip critical, so the bolts in the steel structure is going to be snug tight, but the construction is located in an area that is going to be a freezer. Should the bolt tightening to be checked again after the temperature has dropped (around -25 Celsius)?
 
Yes.

Thermal contraction could be non-trivial.
 
If all of the plies in the joint are steel, then the expansion/contraction should be similar. You should have a look at what the RCSC indicates for thermal breaks (attached). Also, you could consider placing conical washers in the connection to maintain tension if there is some sort of thermal mismatch.
 
 https://files.engineering.com/getfile.aspx?folder=bd87884b-489f-47ed-bec5-fe535f01bf55&file=rcsc_thermal_break.pdf
Hi Navid.Nik

If there is any differential expansion between the bolts and the clamped components then you could have issues with the parts becoming loose or bolt failure.
I would calculate the bolt stresses at room temperature and then recalculate the bolt stress at the lower temperature, you should also check the stresses on the clamped parts for both room and working temperature.
When you get some idea of the stresses at the two extremes, I would try and select a room temperature torque / axial bolt load that won't cause issues when in service.

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein
 
More info: bolt material, diameter, length.

Regards
 
Normally I'm a big advocate for QC process, but in this instance you're not specifying torque and the joint likely isnt seeing any more than natural temperature gradients so wont see a significant effect.
 
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