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Appendices 
3-II.3.2 Cyclic loading transverse to the pile axis 
Lateral cyclic loading of pile foundations leads to a deflection of the pile head which, if large 
enough, places considerable stress on the soil close to the pile head, with pile deflection in 
creasing with the number of load cycles. Also, bedding resistance (bedding capacity and bed 
ding stiffness) may be reduced, if cyclic loading causes an accumulation of pore water excess 
pressure. 
Moreover, in cohesive soils under water, permanent soil deformation may cause gap forma 
tion between pile and soil, and a destabilisation of the near-surface area, which reduces the 
bearing capacity of laterally loaded piles. 
Notes on the assessment of the serviceability of piles that are mainly loaded transverse to the 
pile axis can be found in EA-Pfähle. 
In order to verify the ultimate limit state for the lateral bearing capacity of a pile, it is necessary 
to determine the expected reduction of mobilisable bedding resistance taking into account 
the pile system used (type, diameter), type of soil and number of load cycles. The assessment 
can be made either on the basis of experience or can be based on the results of suitable cyc 
lic laboratory tests taking into account changes of pore water pressure. Bearing capacity can 
be verified on the basis of bedding resistance, which may be diminished, applying the method 
described in chapter 13 of EA Pfähle, and using the “p-y method”. In verifying serviceability 
and load capacity, application areas and limits of the methods chosen shall be taken into ac 
count. 
The influence of changes of pore water pressure on the load bearing capacity shall be exami 
ned and taken into account, where applicable. 
Appendix 3-MI Dynamic pile load tests 
According to DIN EN 1997- (EC 7-1) and DIN 1054, the external axial bearing capacity of foun 
dation piles is verified by means of pile load tests. Therefore, dynamic pile load tests are re 
quired to verify the bearing capacity of offshore wind turbine foundations, where piles are 
predominantly subject to axial loading. 
DIN EN 1997-1 (EC 7-1) and DIN 1054, with reference to EA-Pfahle, describe the methods to 
be used in conducting dynamic pile load tests and evaluating and interpreting the results. The 
geotechnical planning expert shall determine the number and the locations of the pile test 
loads to be conducted in accordance with EA-Pfahle. Generally, dynamic pile load tests shall 
be carried out at all offshore stations and at least 10 % of the offshore wind turbine locations, 
which should include at least two locations for each geotechnical location type found in the 
area of the wind farm. 
The concept for the dynamic pile load tests (number, locations) shall be developed by the 
geotechnical planning expert and submitted with the application documents for the 2 nd re 
lease. The concept should specify the type and scope of tests to be carried out and the way 
in which the test results are to be applied to the entire construction site. The following docu 
ments are to be included: A report from the company conducting the dynamic pile load tests, 
incl. information on the planned sensors, their installation and the planned cable-laying proce 
dure, as well as a confirmation with regard to the feasibility of the dynamic pile load tests 
compiled by the author of the design which gives consideration to all the relevant impacts on 
the foundation during the installation process (e.g. taking into account a cofferdam for instal 
ling the sensors and the laying of the cables).