We are installing a 3/8 Kiwk Bolt TZ2 carbon steel anchor, but have accidentally torqued it to 25 lbf-ft instead of the
recommended 30 lbf-ft. The anchor is no longer accessible without great difficulty.
Is there any code provision (e.g. reliability tests under ACI 355.2) to allow this under-torquing to be analyzed (e.g. by applying a reduction factor to design capacities) or accepted as is without going back and re-torquing to the recommended installation torque?
We are using CSA A23.3 Annex D for our anchorage design.
Hi Billy,
If the anchors are under-torqued or over-torqued, anchor performance may be affected. Usually, it is recommended to follow few guidelines to retorque the anchors to the specified value given in the anchor's installation instructions, however it seems this is not a possibility in your application. Please refer to the “How Installation Torque Can Affect Expansion Anchors” article on the Structure Magazine for more information and to help with your engineering judgement.