Part 3.11 Structural Design Manuals
This Part of the Housing Provisions contains a list of deemed-to-satisfy codes (structural design manuals) that can be used to design building elements using engineering principles.
These provisions can be used in conjunction with both the Performance Requirements (listed in Section 2) and the Deemed-to-Satisfy Provisions (listed in Section 3 — Parts 1 to 12). This combined approach is acceptable and meets the requirements of the Housing Provisions.
Where it is proposed to use an alternative structural design manual as a Performance Solution to that described in Part 3.11, that proposal must comply with—
- ; and
- the relevant Performance Requirements determined in accordance with 1.0.7.
Acceptable construction manuals
is satisfied by complying with—
the relevant provisions of other Parts of Section 3 of the Housing Provisions relating to structural elements; or
any combination thereof.
3.11.2 Resistance to actions
The resistance of a building or structure must be greater than the most critical action effect resulting from different combinations of actions, where—
the most critical action effect on a building or structure must be determined in accordance with 3.11.3 and the general design procedures contained in AS/NZS 1170.0; and
the resistance of a building or structure must be determined in accordance with 3.11.6.
3.11.3 Determination of individual actions
The magnitude of individual actions must be determined in accordance with the following:
the design or known dimensions of the building or structure; and
the unit weight of the construction; and
the known loads that will be imposed during the occupation or use of the building or structure; and
Wind, snow and earthquake actions:
the applicable annual probability of design event for safety, determined by—
assigning the building or structure an Importance Level in accordance with Table 3.11.3a; and
determining the corresponding annual probability of exceedance for safety in accordance with Table 3.11.3b; and
for wind actions, AS/NZS 1170.2 or AS 4055; and
for snow and ice actions, AS/NZS 1170.3; and
for earthquake actions, AS 1170.4.
In cyclonic areas, metal roof cladding, their connections and immediate supporting members must be capable of remaining in position notwithstanding any permanent distortion, fracture or damage that might occur in the sheet or fastenings under the pressure sequences A to G defined in Table 3.10.1.
For the purposes of (d), cyclonic areas are those determined as being located in wind regions C and D in accordance with Figure 126.96.36.199.
Action not covered in (a), (b) and (c) above:
the nature of the action; and
the nature of the building or structure; and
the Importance Level of the building or structure determined in accordance with Table 3.11.3a; and
For the purposes of (f) the actions include but are not limited to—
liquid pressure action; and
ground water action; and
rainwater action (including ponding action); and
earth pressure action; and
differential movement; and
time dependent effects (including creep and shrinkage); and
thermal effects; and
ground movement caused by—
swelling, shrinkage or freezing of the subsoil; and
landslip or subsidence; and
siteworks associated with the building or structure; and
Table 3.11.3a IMPORTANCE LEVELS OF BUILDINGS AND STRUCTURES
|Importance Level||Building types|
|1||Buildings or structures presenting a low degree of hazard to life and other property in the case of failure.|
|2||Buildings or structures not included in Importance Level 1.|
provides a generic description of building types to which Importance Levels have been assigned. The "Importance Level" concept is applicable to building structural safety only. More specific examples are provided in the following Table. The examples are indicative and not exhaustive.
|Importance Level||Examples of building types|
|1||Isolated minor Class 10a buildings and Class 10b structures.|
Class 1 buildings.
Class 10a buildings and Class 10b structures associated with Class 1 buildings.
Note: Importance Levels must be assigned on a case by case basis and relate to the hazards to human life and other property in the event of the structure's failure. For example—
- Importance Level 1 is for minor isolated structures that rarely contain people, are not required as part of normal infrastructure and present a low risk to life and other property.
- Importance Level 2 includes domestic housing and structures intended to contain reasonable numbers of people under normal operations.
Table 3.11.3b DESIGN EVENTS FOR SAFETY
|Importance Level||Annual probability of exceedance|
3.11.4 * * * * *
This clause has deliberately been left blank.
3.11.5 * * * * *
This clause has deliberately been left blank.
3.11.6 Determination of structural resistance of materials and forms of construction
The structural resistance of materials and forms of construction must be determined in accordance with the following:
Cold-formed steel structures: AS/NZS 4600.
Residential and low-rise steel framing: NASH Standard – Residential and Low-Rise Steel Framing, Part 1.
Steel structures: AS 4100.
AS/NZS 1664 Part 1.
AS/NZS 1664 Part 2.
Masonry (including masonry-veneer, unreinforced masonry and reinforced masonry):
AS 4773 Parts 1 and 2.
Composite steel and concrete:
AS 2047 for the following glazed assemblies in an external wall:
Windows excluding those listed in (ii).
Sliding and swinging glazed doors with a frame, including french and bi-fold doors with a frame.
Window walls with one piece framing.
AS 1288 for all glazed assemblies not covered by (i) and the following glazed assemblies:
All glazed assemblies not in an external wall.
Skylights, roof lights and windows in other than the vertical plane.
Sliding and swinging doors without a frame.
Windows constructed on site and architectural one-off windows, which are not design tested in accordance with AS 2047.
Second-hand windows, re-used windows and recycled windows.
Glazing used in balustrades and sloping overhead glazing.
Garage doors and other large access doors in openings not more than 3 m in height in external walls of buildings determined as being located in wind region C or D in accordance with Figure 188.8.131.52:
The reference to heritage windows in 3.11.6(i)(ii)(H) is intended to apply to windows in heritage buildings. The method of determining a heritage building is normally covered by the relevant State or Territory authority.
The weight of roof or ceiling insulation, particularly if additional ceiling insulation is used for compliance with the energy efficiency provisions, needs to be considered in the selection of plasterboard, plasterboard fixings and building framing.
3.11.7 Structural software
Structural software used in computer aided design of a building or structure, that uses design criteria based on the Deemed-to-Satisfy Provisions of the Housing Provisions, including its referenced documents, for the design of steel or timber trussed roof and floor systems and framed building systems, must comply with the ABCB Protocol for Structural Software.
Structural software referred to in (a) can only be used for buildings within the following geometrical limits:
The distance from ground level to the underside of eaves must not exceed 6 m.
The distance from ground level to the highest point of the roof, neglecting chimneys, must not exceed 8.5 m.
The building width including roofed verandahs, excluding eaves, must not exceed 16 m.
The building length must not exceed five times the building width.
The roof pitch must not exceed 35 degrees.
The requirements of (a) do not apply to design software for individual frame members such as electronic tables similar to those provided in—
AS 1684; or
does not apply where a software package simply eliminates manual calculations and the process of the package requires identical methodology as that undertaken manually, (e.g. AS 1684 span tables and bracing calculations).