| Standard | Title | Reference Tools | Reference Table |
|---|---|---|---|
| EN 1990 | Basis of structural design - general principles, reliability, load combinations | ||
| EN 1990 Annex A1 | Application for buildings | ||
| EN 1990 Annex A2 | Application for bridges | - | - |
What this standard covers
EN 1990 (Eurocode - Basis of structural design) is the head document of the Eurocode system. It does not design anything itself: it sets the limit-state framework, the partial factors and the combination rules that every other Eurocode part is applied within.
EN 1990 establishes design by limit states - ultimate limit states, which concern collapse and safety, and serviceability limit states, which concern deflection, vibration and cracking under everyday use. It defines the partial factor format in which characteristic values of actions and material properties are converted into design values, and it fixes the combination expressions in which several actions are considered acting together.
It also sets the reliability framework behind those numbers: consequence classes, design working life, and the treatment of accidental and seismic design situations. Because it is the head document, its factors and combinations apply across concrete, steel, composite, timber, masonry, geotechnical and aluminium design alike - a design to any other Eurocode part is incomplete without it.
What you will find in it
- Limit states
- The distinction between ultimate limit states (strength, stability, rupture) and serviceability limit states (deflection, vibration, cracking), and what has to be verified for each.
- Partial factors
- The gamma factors applied to permanent and variable actions and to material properties, which convert characteristic values into the design values used in a check.
- Combination factors
- The psi coefficients that reduce accompanying variable actions, recognising that wind, snow and imposed load are unlikely to reach their maxima simultaneously.
- Combinations of actions
- The fundamental, characteristic, frequent and quasi-permanent expressions - which combination applies depends on whether the check is ultimate or serviceability.
- Design situations
- Persistent, transient, accidental and seismic situations, each with its own set of factors and its own combination expression.
- Consequence classes
- The classification of a structure by the consequence of its failure, and the reliability differentiation that follows from it.
When to use this standard
Open EN 1990 whenever you need a combination of actions or a partial factor, in any material. It is the first document consulted on a Eurocode project and the last one that stays relevant, because every member check in EN 1992 to EN 1999 is carried out on load effects that EN 1990 defined.
How it fits with the other standards
EN 1990 sits above the whole system: actions are quantified in EN 1991, then combined by EN 1990, and the resulting effects are checked against member resistances from EN 1992 (concrete), EN 1993 (steel), EN 1994 (composite), EN 1995 (timber), EN 1996 (masonry) or EN 1999 (aluminium), with EN 1997 for the ground and EN 1998 for seismic design.
What each part covers
- EN 1990
- The head document itself: limit states, design situations, the partial factor format, and the reliability framework of consequence classes and design working life that sits behind the numbers.
- EN 1990 Annex A1
- Application to buildings. This is where the partial factors and the psi combination coefficients for buildings actually live, together with the combination expressions for ultimate and serviceability checks.
- EN 1990 Annex A2
- Application to bridges. The equivalent annex for bridge structures, with its own factors, combination rules and serviceability criteria including traffic-induced deformation.