When calculating a connection that has a single anchor with a stand-off base plate without clamping with a shear force applied the check for pryout failure does not consider the effects of the moment due to the set-off distance (lever arm). However the check for steel failure does consider this lever arm. Why is the moment due to the lever arm ignored in the pryout failure check? See attached example calculation
Hello Brent,
Thank you for reaching out to Hilti.
As per AS5216 (Cl 7.2.4), pry out failure for post installed chemical anchors is calculated as a minimum of the concrete cone breakout or pull out failure multiplied with a factor of safety. AS5216 states that the verification of lever arm pry out shall not be required for post-installed fasteners subjected to shear load since this interaction is accounted for in Equation 7.2.2.3(2). For this condition, the pry out failure is only checked for the bond of HUS4-Max.
Moreover, for lever arm conditions, the steel is typically the most critical failure mode and thus steel will likely fail prior to pry out failure.
Hope this helps
kind regards
Ask Hilti Team
Australia