Description

The P21 test method has been in existence since 1979, with a supplement published in 1991 to reflect the change from working stress design to limit states design. It is cited in NZS 3604 Timber framed buildings and is still in regular day-to-day use to determine wind and earthquake ratings of bracing elements generally within the scope of NZS 3604.

This version was updated prior to, and in anticipation of NZS 3604:2011.

Scope

Bracing ratings evaluated in accordance with this procedure are intended to be used for the design of buildings coming within the scope and framework of NZS 3604 Timber framed buildings.

Therefore, the methodology is focused on the determination of bracing ratings of timber-framed elements whose resistance is basically dependent on the behaviour of steel fasteners, installed into the timber frame, under lateral (shear) loading. The procedure is not intended to be used for evaluating the performance of concrete or masonry walls, steel-framed walls, post and beam, plank construction or panellised construction, unless the critical components of the wall are laterally loaded steel fasteners installed in timber.

(Note: The scope includes, but is not limited to, elements with sheet linings or claddings (for example, gypsum plasterboard, plywood, fibre-cement, OSB or MDF), strip cladding or lining (for example, weatherboards, board and batten, match lining), steel or timber diagonal braces fixed to the frame. Refer to Section 14 for application of this test procedure, which discusses these issues.)

The bracing ratings derived are only applicable to the construction tested.