Enter your characteristic actions and get every EN 1990 combination — ULS equations 6.10a and 6.10b with the UK National Annex ξ = 0.925, and the SLS characteristic, frequent and quasi-permanent cases — with the governing value identified and every ψ factor shown.
Free, no sign-up. It runs entirely in your browser, so nothing you enter leaves your machine.
Enter characteristic (unfactored) values in any consistent unit — kN, kN/m or kN/m². The combinations are linear, so the output carries the same unit you put in.
Both. EN 1990 asks for the less favourable of the two, so you evaluate each and take the larger. They trade the permanent action against the leading variable one.
In 6.10b the permanent action is reduced by ξ = 0.925 (UK NA Table NA.A1.2(B)), giving 0.925 × 1.35 = 1.2488, in exchange for applying the full 1.5 to the leading variable action. For ordinary buildings where imposed load dominates, 6.10b usually governs. Equation 6.10a takes over when the permanent action is large relative to the variable ones — heavy concrete construction with light imposed loading.
When dead load helps — resisting uplift, overturning, sliding, or on a cantilever back-span — you must not rely on load you might not have. The permanent factor drops to γG,inf = 1.00. The calculator reports both cases; use the favourable one wherever a lighter structure is the worse case for the check in hand.
| Action | Symbol | ULS | SLS |
|---|---|---|---|
| Permanent — unfavourable | γG,sup | 1.35 | 1.00 |
| Permanent — favourable | γG,inf | 1.00 | 1.00 |
| Variable — unfavourable | γQ | 1.50 | 1.00 |
| Variable — favourable | γQ | 0 | 0 |
| Reduction on Gk in 6.10b | ξ | 0.925 | — |
ψ0 for combination values, ψ1 for the frequent case, ψ2 for quasi-permanent. Storage is the one everybody forgets — its ψ values are far higher than an office.
| Action | ψ0 | ψ1 | ψ2 |
|---|---|---|---|
| Imposed A/B — domestic, office | 0.7 | 0.5 | 0.3 |
| Imposed C — assembly areas | 0.7 | 0.7 | 0.6 |
| Imposed D — shopping | 0.7 | 0.7 | 0.6 |
| Imposed E — storage | 1.0 | 0.9 | 0.8 |
| Imposed F — parking ≤ 30 kN | 0.7 | 0.7 | 0.6 |
| Imposed G — parking 30–160 kN | 0.7 | 0.5 | 0.3 |
| Imposed H — roofs | 0.7 | 0 | 0 |
| Wind | 0.5 | 0.2 | 0 |
| Snow — altitude ≤ 1000 m | 0.5 | 0.2 | 0 |
| Snow — altitude > 1000 m | 0.7 | 0.5 | 0.2 |
| Combination | Equation | Use it for |
|---|---|---|
| Characteristic | 6.14b | Irreversible effects — cracking of brittle finishes, permanent damage |
| Frequent | 6.15b | Reversible effects — comfort, vibration, function of equipment |
| Quasi-permanent | 6.16b | Long-term effects — creep deflection in concrete and timber |
Volex Anvil designs RC, steel, timber, masonry and foundations to the Eurocodes — clause-referenced and validated against published worked examples (359/359 checks pass).