Bracing capacity
Bracing capacity is the racking resistance a bracing element or wall provides (kN/m) under AS 1684. It must meet or exceed the bracing demand for each wall line.
Ask Chalkline about this →Bracing capacity is the horizontal racking resistance a bracing element or braced wall provides, the strength side of the bracing equation. Under AS 1684.2, it is rated in kilonewtons per metre (kN/m) of installed bracing, or as a capacity per panel, and is sometimes expressed in bracing units (BU).
Capacity versus demand. Bracing has two sides:
- Demand: the racking force the wind puts on a wall line, set by the wind classification, building geometry, and wall length.
- Capacity: the resistance the chosen bracing provides.
A wall line passes when its total bracing capacity meets or exceeds the demand. This balance is worked through for every wall line in both directions during the AS 1684 bracing design (see wall bracing for the full calculation).
How it is rated. Each bracing type has a rated capacity from AS 1684.2 Table 8.18: a standard plywood sheet bracing panel rates around 1.5 kN/m, enhanced fixing methods much higher, and diagonal strap or angle braces lower (verified 2026-05-25, AS 1684.2 Table 8.18 as cited in wall bracing). Proprietary systems carry the capacity tested by the manufacturer.
The rating assumes the fixing. A bracing panel only delivers its rated capacity if it is fixed with the specified fastener type, size, and spacing. Reduce the nailing and the capacity drops in proportion, which is why field substitutions void the schedule.
Also known as: racking capacity, bracing resistance.
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Last updated: 2026-05-25. Verified: 2026-05-25. Quarterly review for currency.