Earthquake
This tool verifies the omission criteria to determine whether further earthquake calculations are required according to clause NA.3.2.1(5) in NS-EN 1998-1:2004+A1:2013+NA:2021.
For structures in seismic class I–IIIa, verification against seismic action per NS-EN 1998 may be omitted when any of the following criteria is satisfied:
1. Structures in seismic class I.
2. Structures on ground types A–E where the ground acceleration including amplification satisfies agS ≤ 0.50 m/s².
3. Structures on ground types A–E where the ground acceleration satisfies ag ≤ 0.30 m/s².
4. Structures on ground types A–E with a design working life ≤ 2 years.
Criterion 5 from the omission criteria is not included and is therefore not checked in this tool.
For seismic classes IIIb and IV, verification against seismic action per NS-EN 1998 is always required.
