Design concept
The design of reinforced concrete structures in the seismic situation for seismic zones can be divided into the following steps. [1]
1 - Definition of design parameters 2 - Selection of the structure 3 - Structural design 4 - Seismic analysis 5 - Ultimate limit state design 6 - Capacity design
Ductility classes
In order to withstand earthquakes, structures must be designed according to Eurocode 8 either for low dissipative energy dissipation capacity or for sufficient capacity to dissipate energy.
There are two levels of seismic design that can be applied alternatively:
- Medium ductility class (ductility class medium, DCM) - This requires the use of low behaviour factors and allows lower requirements for the deformation capacity (ductility) of the structural components.
- High ductility class (ductility class high, DCH) - For this class, higher behaviour factors may be used. However, the requirements for the deformation capacity of the structural components are correspondingly high.
For concrete structures, seismic design according to the low ductility class (ductility class low, DCL) is also permissible as an alternative, where the design is carried out only according to EC 2. However, it is recommended only for low seismicity.
Dimensioning of reinforced concrete components
The following subchapters deal with the component-specific dimensioning for the seismic situation.