AS 1170.4:2007 pdf – Structural design actions Part 4: Earthquake actions in Australia.
accordance with the general principles of Clause 5.2, the provisions of the appropriate earthquake design category (see Clauses 5.3, 5.4 or 5.5) and the requirements of the applicable material design Standards.
5.2.1 Seismic-force-resisting system
All structures shall be configured with a seismic-force-resisting system that has a clearly defined load path, or paths, that will transfer the earthquake actions (both horizontal and vertical) generated in an earthquake, together with gravity loads, to the supporting foundation soil.
5.2.2 Tying structure together
All parts of the structure shall be tied together both in the horizontal and the vertical planes so that forces generated by an earthquake from all parts of the structure, including structural and other parts and components. are carried to the foundation.
Footings supported on piles, or caissons. or spread footings that are located in or on soils with a maximum vertical ultimate bearing value of less than 250 kPa shall be restrained in any horizontal direction by ties or other means, to limit differential horizontal movement during an earthquake.
5.2.3 Performance under earthquake deformations
Stiff components (such as concrete, masonry, brick, precast concrete walls or panels or stair walls, stairs and ramps) shall be—
(a) considered to be part of the seismic-force-resisting system and designed accordingly; or
(b) separated from all structural elements such that no interaction takes place as the structure undergoes deflections due to the earthquake effects determined in accordance with this Standard.
All components, including those deliberately designed to be independent of the seismic- force-resisting system, shall be designed to perform their required function while sustaining the deformation of the structure resulting from the application of the earthquake forces determined for each limit state.
Floors shall be—
(I) continuous over a series of internal walls at right angles or near right angles; or
(ii) tied to supporting walls at all supported edges.
Provision shall be made for floors to span without collapse if they become dislodged from edges to which they are not tied.
5.2.4 WaIls
Walls shall be anchored to the roof and restrained at all floors that provide horizontal support for the wall. Walls shall be designed for in-plane and out-of-plane forces.
Out-of-plane forces on walls shall be designed in accordance with Section 8.
The structural system shall be designed to resist the most critical action effect arising from the application of the earthquake actions in any direction.
Except for structure components and footings that participate in resisting horizontal earthquake forces in both major axes of the structure, this provision shall be deemed to be satisfied by applying the horizontal force in the direction of each of the major axes of the structure and considering the effect for each direction separately.
For structure components and footings that participate in resisting horizontal earthquake forces in both major axes of the structure, the effects of the two directions determined separately shall be added by taking 100% of the horizontal earthquake forces for one direction and 30% in the perpendicular direction.
Forces shall be applied at the centre of mass of each floor except where offset from the centre of mass is required for the consideration of torsion effects (see Clause 6.6).
Connections between components of the structure shall be capable of transmitting an internal ultimate limit state horizontal action equal to the values calculated using this section but not less than 5% of the vertical reaction arising from the seismic weight or 5% of the seismic weight of the component which ever is the greater. Earthq ziake firces—Equivalent static method
Earthquake forces shall be calculated using the equivalent static method, in accordance with Section 6 except where covered by Clause
NOTE: Dynamic analysis, in accordance with Section 7, may be used if desired (see Clause 2.2).