High-Strength Structural Bolt Assembly AS/NZS 1252.1

AS/NZS 1252.1 is the Australian/New Zealand standard for high-strength steel fastener assemblies used in structural engineering. The standard covers matched assemblies comprising a property class 8.8 high-strength steel bolt, a property class 8 nut with ISO metric coarse pitch threads, and an associated hardened and tempered steel washer.

The principal dimensional range is M12 to M36, with M22 and M27 identified as non-preferred thread diameters.

The assemblies are used for bolted connections in structural steelwork, including building structures, fabricated steelwork, infrastructure and other applications where high-strength mechanical connections are required.

Depending on the engineering specification and connection design, AS/NZS 1252.1 assemblies may be used in snug-tight or fully tensioned conditions. The standard also addresses testing requirements related to the suitability of assemblies for tensioning and preloading.

For procurement, the bolt, nut and washer should be treated as a matched assembly rather than as unrelated individual components.

Surface coatings also need to be compatible across the assembly. Common supply conditions include uncoated and hot-dip galvanized configurations, while coated assemblies require appropriate coating and compatibility controls.