Design regulations#

As described in Crowley et al. (2021b), the following categories of seismic design have been identified accross Europe:

  • CDN: no seismic design (i.e. typically before the 1960s), leading to buildings that were designed using allowable stresses, having very low material strength values and considering the gravity loads only;

  • CDL: low code (i.e. the first generation of seismic design codes), referring to buildings that were designed considering the seismic action by enforcing values of a seismic coefficient (or lateral force coefficient);

  • CDM: moderate code (i.e. the second generation of seismic design codes), which considers modern concepts of ultimate capacity and partial safety factors (limit state design) and/or with better detailing to improve global ductility;

  • CDN: high code (i.e. the latest generation of seismic design codes), which accounts for modern seismic design principles accounting for capacity design and local ductility measures, similar to those available in Eurocode 8 for ductility class medium (which is assumed to reflect the most frequently adopted ductility class).

Crowley et al. (2021b) also report a summary table with the years when these design classes were introduced in each of the European countries with a brief history of seismic design in the region, as well as the years when relevant updates to the seismic zonation maps were made. Other technical details about design regulations in Europe are available in the references collected below.


Crowley H., Dabbeek J., Despotaki V., Rodrigues D., Martins L., Silva V., Romão, X., Pereira N., Weatherill G., Danciu L. (2021a) - European Seismic Risk Model (ESRM20), EFEHR Technical Report 002, V1.0.0,

Crowley H., Despotaki V., Silva V., Dabbeek J., Romão X., Pereira N., Castro J.M., Daniell J., Veliu E., Bilgin H., Adam C., Deyanova M., Ademović N., Atalic J., Riga E., Karatzetzou A., Bessason B., Shendova V., Tiganescu A., Toma- Danila D., Zugic Z., Akkar S., Hancilar U. (2021b) - Model of Seismic Design Lateral Force Levels for the Existing Reinforced Concrete European Building Stock. Bulletin of Earthquake Engineering, 19, 2839–2865,