| Standard | Title | Reference Tools | Reference Table |
|---|---|---|---|
| EN 1991-1-1 | Densities, self-weight, imposed loads for buildings | - | - |
| EN 1991-1-2 | Actions on structures exposed to fire | - | - |
| EN 1991-1-3 | Snow loads | - | - |
| EN 1991-1-4 | Wind actions | ||
| EN 1991-1-5 | Thermal actions | - | - |
| EN 1991-1-6 | Actions during execution | - | - |
| EN 1991-1-7 | Accidental actions | - | - |
| EN 1991-2 | Traffic loads on bridges | - | - |
| EN 1991-3 | Actions induced by cranes and machinery | - | - |
| EN 1991-4 | Silos and tanks | - | - |
What this standard covers
EN 1991 (Eurocode 1 - Actions on structures) is the part of the Eurocodes that quantifies loads. It covers self-weight and imposed loads, snow, wind, thermal actions, fire actions, loads during execution, accidental actions and traffic loads on bridges.
EN 1991 is a family rather than a single document. EN 1991-1-1 gives densities, self-weight and imposed loads by occupancy; EN 1991-1-2 gives actions on structures exposed to fire; EN 1991-1-3 snow; EN 1991-1-4 wind; EN 1991-1-5 thermal actions; EN 1991-1-6 actions during execution; and EN 1991-1-7 accidental actions such as impact and explosion.
The wind part is the one most often used in building design and the most involved: it works from a basic wind velocity for the site through terrain roughness, orography and height to a peak velocity pressure, then applies pressure coefficients that depend on the building form and the surface being considered. Many of its inputs are set nationally, so the National Annex is required to complete a calculation.
What you will find in it
- Densities and self-weight
- Unit weights of construction materials and stored materials, used to build up permanent actions from the real build-up rather than an assumed allowance.
- Imposed loads
- Imposed loads by category of use, together with the reductions permitted for large floor areas and for columns carrying several storeys.
- Snow loads
- Ground snow load for a site, the shape coefficients for roof forms, and the treatment of drifting and of snow that slides or is obstructed.
- Wind actions
- Basic wind velocity, terrain and orography, peak velocity pressure, and the external and internal pressure coefficients for walls, roofs and elements.
- Thermal actions
- Temperature change and gradient, which drive movement and, where restrained, force - relevant to long structures and to bridges in particular.
- Actions during execution
- Loads that only exist while the structure is being built, a condition that often governs members that are lightly loaded in service.
- Accidental actions
- Impact, explosion and the general principles of robustness and of limiting the consequence of a local failure.
When to use this standard
Use EN 1991 to establish what loads act on a structure, before any member is sized. It gives characteristic values of the actions; EN 1990 then combines them, and the material Eurocodes check the members. For wind in particular, the National Annex of the country of construction must be used alongside it.
How it fits with the other standards
Actions from EN 1991 are combined using EN 1990 and then applied to designs to EN 1992, EN 1993, EN 1994, EN 1995, EN 1996 or EN 1999. Seismic action is not in EN 1991 - it is given by EN 1998.
What each part covers
- EN 1991-1-1
- Densities, self-weight and imposed loads. Unit weights of construction and stored materials, imposed loads by category of use, and the reductions permitted for large areas and multi-storey columns.
- EN 1991-1-2
- Actions on structures exposed to fire. The thermal and mechanical actions during a fire, including the nominal and parametric fire curves - the material fire parts then check the member.
- EN 1991-1-3
- Snow loads. Ground snow load for the site, the shape coefficients for roof forms, and the treatment of drifting, sliding and obstructed snow.
- EN 1991-1-4
- Wind actions. The part used most often in building design: basic wind velocity, terrain and orography, peak velocity pressure, and pressure coefficients for walls, roofs and elements.
- EN 1991-1-5
- Thermal actions. Uniform temperature change and temperature gradient, which cause movement and, where restrained, force - significant for long buildings and bridges.
- EN 1991-1-6
- Actions during execution. Loads that exist only while the structure is being built, which often govern members that are lightly loaded in the finished state.
- EN 1991-1-7
- Accidental actions. Impact and explosion, and the general strategies for robustness that limit the consequence of a local failure.
- EN 1991-2
- Traffic loads on bridges. The road, rail and pedestrian load models applied to bridge decks, including the fatigue load models.
- EN 1991-3
- Actions induced by cranes and machinery. Wheel loads, dynamic factors and the actions from vibrating machinery on their supporting structures.
- EN 1991-4
- Silos and tanks. The pressures exerted by stored bulk solids and liquids, which depend on the material, the geometry and whether the silo is filling or discharging.