Appendices 
101 
3-I.4 Cyclic loads on measurement masts, cable towers and comparable structures 
The design of the foundation elements of measurement masts, cable towers and comparable 
structures with respect to cyclic loads shall be addressed according to their respective cons 
truction types and stress spectrums and in accordance with the requirements and regulations 
specified in sections 3-I.2 and 3-I.3. 
Appendix 3-M Verification of the limit states for foundation elements taking into ac 
count cyclic loading 
3-11.1 Preliminary remarks 
Ultimate limit states of bearing capacity and serviceability taking into account cyclic loading 
effects have to be calculated both for shallow and deep foundations of offshore wind turbines. 
Based on general experience gained so far and, alternatively, the state of current scientific 
and technical progress, the following information is provided on the verification methods to be 
used. 
In as far as cyclic laboratory tests are conducted to obtain the verification, these shall be pl 
anned and conducted in close consultation between the geotechnical expert and the author 
of the foundation design. Appropriate documentation is part of the verification documentation 
required for the final design for the 2 nd release. For further information on cyclic laboratory 
tests, please refer to Standard Ground Investigations. 
3-II.2 Shallow foundations (heavyweight foundations) 
To verify the load bearing capacity of shallow foundations using conventional geotechnical 
methods, the decrease in load bearing capacity can be evaluated in a simplified manner by 
means of cyclic shear tests on undrained soil samples (e. g. using the cyclic triaxial test de 
vice; please also refer to Savidis & Schuppe, 1982). 
Verification of the serviceability of shallow foundations can be conducted in observance of the 
recommendations provided in chapter E4 of the directive “Subsoil Dynamics” published by 
the DGGT study group 1.4. The examples provided herein can be applied to the shallow foun 
dations of offshore wind turbines. 
Further to the basic design rules set out in DIN EN 1997 (EC 7-1) and DIN 1054, steps shall be 
taken to ensure that soil erosion below the foundation due to cyclic loading is prevented. With 
respect to shallow foundations with no circumferential skirts of adequate penetration depth, 
this normally means that gap formation must be prevented - even where typical and continual 
loads are combined with variable loads in the most unfavourable combination possible. 
3-II.3 Pile foundations 
3-11.3.1 Axial cyclic loading 
For verification processes and formats, please refer to EA-Pfahle. 
Please note that the processes mentioned herein have initially only been tested within the 
framework of research projects and that these have been partially calibrated to model and 
large scale tests. Project-related application experience is not yet available.