Installations where “thru-bolts” are used to make UNISTRUT® connections require special torque considerations compared to channel nut torque requirements. Unlike channel nut attachments, “thru-bolts” induce a compressive load into the channel sidewalls, and the torque must be set to avoid side wall buckling. Typical “thru-bolt” connections as shown below.
Torque values for “Thru-Bolts” are a function of:
Channel Bearing Strength to Avoid Sidewall Buckling
- Nut Factor Coefficient of Friction (K) – Assumed 0.22 for EG Plating
- Distance from the “Thru-Bolt” to Channel End
Single Channel Thru-Bolt Torque Limits
Double Channel Thru-Bolt Torque Limits