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Part B - Certificates and approval requirements 
The following items are to be considered in particular: 
• Potential reduction in stability of the seabed due to external influences such as current and wave 
action, influenced by the substructure; effect of earthquake; offshore operations such as pile driving 
or dredging, etc. 
• Potential change in the geometry of the seabed due to influences such as erosion (scouring) and 
suffosion 
• Potential change in the arrangement of foundation elements due to influences such as cyclical 
creep of the soil, accumulated deformation (hysteresis) 
• Potential change in the mechanical properties of the soil due to influences such as pore water pres 
sure accumulation (liquefaction), consolidation, deconsolidation. 
It is necessary to demonstrate: 
• that either these mechanisms do not occur 
• or that these mechanisms have been adequately taken into account in the design 
• or that these mechanisms will be adequately observed during installation and operation, and suit 
able measures will be taken to compensate for them if necessary. 
3.2.4.7.2 Certificates for foundation elements 
The minimum scope of investigation, documentation and provision of suitable certificates is as follows: 
• Process engineering of the installation and effects of the installation process 
• Description and modelling of the significant interactions between the soil and the structure as the 
basis and input parameters 
• Demonstrations of the external load capacity of the foundation and its elements 
• Demonstrations of the internal load capacity of the foundation elements 
• Natural frequency analysis of the offshore wind farm 
• The influence of stability properties of the seabed on the stability against collapse and on the serv 
iceability of the foundation, the entire structure and its components 
• Effects of cyclical and dynamic loading („degradation“ and „liquefaction“) 
• Constraint stress on structural elements and add-on components due to permanent soil deformation 
• Safety against shifting of ballast material 
Special certificates are to be provided for pile foundations: 
• Axial pile load capacity and safety (peak resistance and jacket friction) 
• Lateral pile load capacity and safety 
• Axial deformation and shifting estimates (settling, inclination and rotation) 
• Lateral deformation and shifting estimates 
• Pile group effects and interactions between individual foundation elements (e.g. in tripod and jacket 
structures) 
Special certificates are to be provided for heavyweight foundations: 
• Soil loading by the normal soil stress and limitation of the open gap 
• External stability against collapse (safety against tilting, sliding and bearing capacity failure), if nec 
essary with consideration for potential pore water excess pressure build-up. 
Suitable structural design criteria shall be defined for the deformation and shifting certificates based on 
the potential static and dynamic effects on the components and on the structure (e.g. max. permitted 
deflection and rotation at the pile head at the level of the seabed and at the pile foot; max. exploitation of 
the lateral bedding reaction of the soil; minimum or maximum values for soil rigidity). 
An expert assessment shall be undertaken into the effects of the following parameters and how they can 
practically be considered in the certificates: 
• Installation of the foundation elements on the soil and foundation system (e.g. piling; driving aids) 
• Positional shifts of the foundation elements