What does 8.8/TF mean?

Class 8.8 bolts, fully tensioned, in a friction-type connection – the load is carried by friction between the plies.

Structural bolts AS/NZS 1252.1 – property class 8.8

What it is

AS/NZS 1252.1 specifies high-strength structural bolting assemblies – bolt, nut and washer – for steel structures designed to AS 4100 and NZS 3404. The standard requires the components to be tested together as an assembly, with traceable batch documentation.

World Steel supplies AS/NZS 1252.1 assemblies with steel fabricated to AS/NZS 5131, so the bolts that arrive on site match the shop drawings, connection by connection.

Bolting categories

AS 4100 bolting categories
Category	Bolt	Tightening	Joint behaviour
4.6/S	Commercial 4.6 (AS 1111)	Snug-tight	Bearing, light connections, purlins
8.8/S	AS/NZS 1252.1	Snug-tight	Bearing
8.8/TB	AS/NZS 1252.1	Fully tensioned	Bearing, fatigue and reversal
8.8/TF	AS/NZS 1252.1	Fully tensioned	Friction (slip-critical)

Minimum bolt tension – AS 4100
Size	M16	M20	M24	M30	M36
Nti (kN)	95	145	210	335	490

Tightening

Fully tensioned categories are tightened by the part-turn method or with direct tension indicators after a snug-tight condition is reached – ⅓ turn for lengths up to 4d, ½ turn up to 8d, ⅔ turn up to 12d.

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