Bolt Spacing — AS 4100 Edge Distance & Pitch Guide
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Complete reference for bolt spacing, edge distance, and pitch per AS 4100:2020 Clause 9.5. Covers min edge distances, min/max pitch, staggered spacing.
Minimum Edge Distance — Table 9.5.3
| Edge Type | Min Distance |
|---|---|
| Sheared/machine flame-cut | 1.25 df |
| Rolled/autogas-cut | 1.0 df |
| For tearout strength | 1.5 df (recommended) |
| Size | Sheared | Rolled | Tearout |
|---|---|---|---|
| M12 | 18 mm | 15 mm | 20 mm |
| M16 | 22 mm | 18 mm | 26 mm |
| M20 | 28 mm | 22 mm | 32 mm |
| M24 | 32 mm | 26 mm | 38 mm |
| M30 | 40 mm | 32 mm | 48 mm |
Minimum Bolt Spacing — Clause 9.5.2
| Condition | Min c/c |
|---|---|
| Between bolt centres | 2.5 df |
| Tension connection | 3.0 df |
| Slip-critical connection | 3.0 df |
| Size | Min | Tension/Slip |
|---|---|---|
| M12 | 32 | 38 |
| M16 | 42 | 50 |
| M20 | 52 | 62 |
| M24 | 62 | 74 |
Maximum Spacing — Clause 9.5.4
| Condition | Max |
|---|---|
| Compression member | 16 tp or 200 mm |
| Tension member | 24 tp or 300 mm |
| Exposed edge | 12 tp or 150 mm |
| Painted edge | 12 tp or 150 mm |
| Unpainted weathering steel | 8 tp or 100 mm |
Design Resources
- [[Australian Steel Grades|/reference/australian-steel-grades/]] | [[Australian Steel Properties|/reference/australian-steel-properties/]] | [[Australian Beam Sizes|/reference/au-beam-sizes/]] | [[Australian Bolt Capacity|/reference/australian-bolt-capacity/]] | [[AS 4100 Beam Design|/reference/as4100-beam-design-example/]] | [[All Australian References|/reference/]]
FAQ
Minimum edge distance per AS 4100? 1.25df for sheared edges, 1.0df for rolled per Clause 9.5.3.
Minimum bolt spacing per AS 4100? 2.5df between centres. 3.0df for tension and slip-critical connections.
Maximum bolt spacing? Compression: 16tp or 200mm. Tension: 24tp or 300mm. Exposed: 12tp or 150mm.
Educational Use Only — This reference is for educational and preliminary design purposes only. All structural designs must be independently verified by a licensed Professional Engineer (PE) or Structural Engineer (SE) in accordance with AS 4100:2020 and all applicable Australian Standards. Results are not for construction.