Does Head Pull-through Failure Apply for ASSY Self-Tapping Screws with Steel Side Plate Connections?

When detailing axial connections using Assy self-tapping screws, the withdrawal design resistance values must be checked against the axial strength of the screw as well as the capacity of the steel side plate. This failure mode must be checked from first principles and would most likely dictate the thickness of the steel side plate. This check must be carried out following the applicable regional codes and standards pertaining to the head pull-through capacity of steel side plates. It is worth noting that CSA O86-14 Clause 12.11.5.3 only applies to wood screws, and not self-tapping screws as per CCMC Code Approval 13677-R. Thus this check does not apply to Assy self-tapping screws.