SPACE GASS Combination Generator

List your load cases. The page numbers them, builds the AS/NZS 1170.0 combinations, and lays both out to paste straight into the Load Case Titles and Combination Load Cases datasheets.

Step 1

Your load cases

Dead load cases (G)

Live load cases (Q)

The character sets the ψ factors from AS/NZS 1170.0 Table 4.1.

Wind load cases

One case per direction, repeated for each section that sees a different wind. Each case holds ultimate wind; the SLS factor scales it to serviceability wind.

Other actions (snow, liquid, earth, ground water)

Enter the unfactored case. The Cl 4.2.3 factor is applied in the combination.

Earthquake

For each dead or live case ticked “seismic mass”, four acceleration cases are created (+X, −X, +Z, −Z at 1.0 g). They are summed into a seismic weight per direction, multiplied by your coefficient, then used in the ULS and SLS combinations.

Include earthquake Apply 100% + 30% direction rule ULS coefficient, X direction [–] ULS coefficient, Z direction [–] SLS coefficient, X (blank = none) [–] SLS coefficient, Z (blank = none) [–]

Serviceability combinations to generate

AS/NZS 1170.0 Cl 4.3 lists the components but does not prescribe the combinations, so the selection is yours.

Case numbering blocks

Step 2

Load case titles

Paste into the first empty row of the Load Case Titles datasheet. This creates every primary and combination case.

Step 3

Combinations

Paste into the first empty row of the Combination Load Cases datasheet. The header row is part of the paste. After this, the only job left is adding loads to the primary cases.

How each combination is built

Factor grid (what gets pasted)

Factors and clauses used

Assumptions and limits

All dead cases act together and all live cases act together. There is no pattern loading. Other combinations may be required (AS/NZS 1170.0 Cl 4.1).
Wind cases are alternatives, one per combination.
Live cases in the seismic weight use ψc from AS 1170.4:2024 Cl 6.2.2 (0.6 storage, 0.3 all other). The live load in the ULS earthquake combination uses ψE from AS/NZS 1170.0 Table 4.1. These differ for some load characters.
A uniform acceleration multiplied by a coefficient gives the base shear but spreads force by weight. AS 1170.4 Cl 6.3 distributes it by weight and height, so check the method suits structures with more than one level of mass.
Not generated: torsion (AS 1170.4 Cl 6.6), vertical earthquake, stability combinations (AS/NZS 1170.0 Cl 4.2.1) and fire (Cl 4.2.4).
Table 4.1 prints ψc for three concentrated-action rows as “as for distributed floor actions”. The values used here are an interpretation and raise a warning when selected.
Factors are from AS/NZS 1170.0:2002 (Amendments 1 to 5) and AS 1170.4:2024. Confirm the editions your project references.

Independent tool, not affiliated with or endorsed by SPACE GASS. It generates load case numbers and factors only; the engineer remains responsible for checking every combination against the current Standards before use.