Load assumption

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The external forces acting on a structure or on components are called actions . In order to be able to calculate the stability and the serviceability, load assumptions are made about the expected effects.

A distinction is made between permanently acting dead loads and not constantly acting useful and special loads , which are put together in different load cases . The most unfavorable load case in each case results in the assessment basis for the structure or component.

In order to dimension the supporting structure of a building in an economically justifiable manner, one weighs between different combinations of main, additional and special loads and the probability of their occurrence. The risk of damage also plays a role here.

With the large number of different structures, from simple terraced houses to high-rise buildings , bridges , dams or sports stadiums , different load cases have to be calculated.

Dead loads

The constantly acting loads consist of the mass of the supporting structure and the weight of the fixed expansion loads . These dead loads usually remain unchanged over the life of a building and their size can be determined more precisely.

Payloads

The payloads include those loads that can change during the use of the structure. These include payloads, also called operational loads or traffic loads, (e.g. vehicles in a parking garage or a crowd on a bridge ) and environmental influences ( wind load , snow load ). The payloads can mainly be static loads or they can exert dynamic effects on the structure.

Environmental influences

Wind loads

Wind loads do not occur constantly and are variable in size. They affect the structure as pressure , suction and friction forces and can be used in slim structures, e.g. B. towers or masts lead to vibrations . The wind load can be changed by the shape of the building, its height, location and the size of the attack surface.

Snow loads

The snow load depends primarily on the location of the building. There are special maps for this, in which you can read off the snow load zone for the planned location. The shape of the roof also plays an important role, as less snow can remain on very steep roofs.

Special loads

There are also special burdens. This includes replacement loads for special accidents, such as earthquakes or a vehicle impact on a bridge pillar, as well as extraordinary loads during the construction phase.

Norms

  • DIN EN 1990 Eurocode, effects on structures (replaces the DIN 1055 standard, which has since been withdrawn)
  • DIN 1072 road and path bridges; Load assumptions

as well as various DIN standards for special buildings or components

See also

literature

  • Structural number tables , Wendehorst, ISBN 3-519-25002-0
  • Book of tables Bautechnik "Friedrich, ISBN 3-427-54023-5 , publisher: Dümmler Bonn
  • Practical structural analysis "Schreyer / Wagner, parts 1-4, ISBN 3-519-25201-5 , publisher B: G: Teubner Stuttgart
  • Structural Analysis in Examples "Bötzl-Martin, Parts 1-3, Order No. 94 010, Verlag Herman Schroedel Verlag Hannover
  • Schneider, construction tables for engineers, 18th edition, Werner Verlag, Cologne 2008, ISBN 978-3-8041-5236-6
  • Schneider, building tables for architects, 18th edition, Werner Verlag, Cologne 2008, ISBN 978-3-8041-5237-3