No distinction is made in the Steel Structures Standard NZS 3404 (SNZ, 2007) between the design ply bearing capacity for a long slotted hole in which the slot is perpendicular to the direction of the bearing load and a standard circular hole.
No distinction is made in the Steel Structures Standard NZS 3404 (SNZ, 2007) between the design ply bearing capacity for a long slotted hole in which the slot is perpendicular to the direction of the bearing load and a standard circular hole. See figure 1. While the presence of a slotted hole does not reduce ply bearing capacity based on strength, there is increased hole elongation for a given bolt shear force compared to a standard hole. In this article, a design equation based on North American practice is presented for design ply bearing capacity limited by hole elongation. This equation will be applicable for situations such as seismic loading, where increased hole elongation associated with slotted holes loaded transverse to the direction of the bearing load is undesirable.
Kevin Cowie
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