# Eurocode load combinations explained (EN 1990)

> EN 1990 sets the load combinations for European design. Here are the ULS expressions 6.10, 6.10a and 6.10b, the partial and psi factors, and a worked example.

**Category:** Codes & standards  
**Author:** Sam Rivera (Structural engineer · Educator)  
**Published:** 2026-05-20

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EN 1990, the head Eurocode, sets the load combinations used across European structural design. For the persistent ultimate limit state the main expression is 6.10: 1.35 times the permanent actions, plus 1.5 times the leading variable action, plus 1.5 times psi-zero times each accompanying variable action. It reaches the same place as the ASCE 7 combinations by a different route, partial factors plus combination factors, and StructLoads applies both code sets so you can switch between them.

## Actions, not loads

Eurocode calls loads actions, and splits them into permanent actions G (self weight and fixed finishes) and variable actions Q (imposed, snow, wind). The [Eurocodes](https://en.wikipedia.org/wiki/Eurocodes) are a coordinated set, with the actions themselves defined in [Eurocode 1: Actions on structures](https://en.wikipedia.org/wiki/Eurocode_1:_Actions_on_structures) and the combination rules in EN 1990. The split matters because permanent and variable actions take different partial factors.

## The persistent ULS combinations

For strength design, these are the gravity expressions. Here G is permanent, Q is the leading variable, and the other variables are accompanying.

| Expression | Gravity form | Note |
| --- | --- | --- |
| 6.10 | 1.35 G + 1.5 Q + 1.5 psi-zero Qi | Single expression, simpler, more conservative |
| 6.10a | 1.35 G + 1.5 psi-zero Q + 1.5 psi-zero Qi | Leading variable also reduced by psi-zero |
| 6.10b | 0.85 times 1.35 G + 1.5 Q + 1.5 psi-zero Qi | Permanent reduced by the xi factor of 0.85 |

You may use 6.10 on its own, or use the pair 6.10a and 6.10b and design for the more onerous of the two. The pair usually gives a slightly lighter result, which is the practical reason it exists. Within the pair, 6.10b normally governs because it only relaxes the permanent factor; [Alastair Hughes' review of the partial factors](https://www.newsteelconstruction.com/wp/wp-content/uploads/2013/01/Tech1301NSC.pdf) in New Steel Construction notes that 6.10a only overtakes it when self weight exceeds roughly 4.5 times the variable load, and that national annexes adjust xi itself, the UK using 0.925 in place of the recommended 0.85. This is the action side of [limit state design](https://en.wikipedia.org/wiki/Limit_state_design): factor the actions up, factor the resistance down, and confirm the first stays below the second.

## Partial and combination factors

Two kinds of factor appear. The partial factors are 1.35 on unfavourable permanent actions and 1.5 on the leading unfavourable variable action, with favourable permanent actions taken as 1.0. The combination factor psi-zero reduces the accompanying variables, because they are unlikely to peak together: typically 0.7 for imposed loads and 0.5 for snow below 1000 m. The recommended values are in EN 1990 and summarised by the [EU Joint Research Centre](https://eurocodes.jrc.ec.europa.eu/), but national annexes can change them, so confirm your country's values.

## A worked example

Take a column carrying 519 kN permanent action, 270 kN imposed and 30 kN snow, with imposed leading and psi-zero of 0.5 on snow. Expression 6.10 gives 1.35 times 519 plus 1.5 times 270 plus 1.5 times 0.5 times 30, which is 701 plus 405 plus 23, or about 1129 kN. That is the factored design action for the column under Eurocode, comparable to the value you would get from the [ASCE 7 load combinations](/blogs/asce-7-load-combinations-explained) on the same loads.

## How it connects to the takedown

A takedown produces the service actions, the unfactored G and Q, exactly as in the [factored loads vs service loads](/blogs/factored-loads-vs-service-loads) distinction. Eurocode then factors them with the expressions above, and the dead and variable split that feeds them is the same one set out in [dead load vs live load](/blogs/dead-load-vs-live-load-explained). StructLoads reports the governing factored action per support for either code.

## Key takeaways: Eurocode load combinations

The persistent ULS uses 6.10, or the pair 6.10a and 6.10b taking the worse, with 1.35 on permanent actions, 1.5 on the leading variable, and psi-zero reducing the accompanying ones. The factors are recommended values that national annexes can adjust. StructLoads applies the Eurocode set and names the governing case, as a preliminary figure a qualified engineer confirms against the national annex.

## Quick answers

### What are the Eurocode load combinations?
For the persistent ultimate limit state, EN 1990 gives expression 6.10: 1.35 times permanent actions plus 1.5 times the leading variable plus 1.5 times psi-zero times each accompanying variable. An alternative pair, 6.10a and 6.10b, is often less conservative, and design uses the more onerous of the two. Serviceability uses characteristic, frequent and quasi-permanent combinations at lower factors.

### What are the partial factors in Eurocode?
For the persistent ULS, the partial factor on unfavourable permanent actions is 1.35 and on the leading unfavourable variable action is 1.5. Favourable permanent actions take 1.0. These are the recommended values in EN 1990; national annexes can adjust them, so confirm the values for your country before designing.

### What is the psi-zero combination factor?
Psi-zero reduces the accompanying variable actions, because they are unlikely to be at full value at the same instant as the leading action. Typical psi-zero values are 0.7 for imposed loads in normal buildings and 0.5 for snow below 1000 m. The leading variable keeps its full 1.5 factor; the others are multiplied by 1.5 times psi-zero.

### Do you need both 6.10a and 6.10b, or is 6.10 enough?
You may use the single expression 6.10, which is simpler and more conservative, or the pair 6.10a and 6.10b and take the worse of the two, which usually gives a slightly lighter design. Many national annexes specify which to use. If you want one safe expression and do not need the small saving, 6.10 on its own is enough.