1.1 Scope of prEN 1998-5 (1) This document establishes general principles for the design and assessment of geotechnical systems in seismic regions. It gives general rules relevant to all families of geotechnical structures, to the design of foundations, retaining structures and underground structures and complements EN 1997-3 for the seismic design situation. (2) This document contains the basic performance requirements and compliance criteria applicable to geotechnical structures and geotechnical systems in seismic regions. (3) This document refers to the rules for the representation of seismic actions and the description of the seismic design situations defined in EN 1998-1-1 and provides specific definition of the seismic action applicable to geotechnical structures. 1.2 Assumptions (1) The general assumptions of prEN 1990:2021, 1.2, are assumed to be applied. (2) The provisions of this Standard assume that the parties of the project in charge of the analyses, for assessment and possible design of the retrofitting of existing geotechnical structures, have appropriate experience of the type of structures being strengthened or repaired.