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Appendices 
3-1.2.2 Equivalent load spectrum 
In order to assess the impacts of loads of different amplitudes and, possibly, varying direc 
tions, it may be appropriate to derive a cyclic equivalent load (equivalent single-stage spect 
rum) from the design event load. The cyclic equivalent load should comprise a mean load level 
Fmitt, a load amplitude Fampl and an equivalent number of load cycles Neq (please refer to 
Figure 3 1.2). 
Load 
•»•*1 ti iljTTTTI 
_ _ 
T1 r AM« '«U 
Load 
.... 
— 
Number 
of cycles 
Urr 
H, N, 
N. 
N. 
Number 
of cycles 
N 
u 
Number 
of cycles 
Figure 3-1.2 Definition of the equivalent number of load cycles and load amplitude (please com 
pare with EA-Pfahle) 
The establishment of the equivalent single-stage spectrum shall be undertaken in considera 
tion of the selected verification process as well as the boundary conditions specific to the lo 
cation and the foundation element, whereby the appropriateness of this simplification shall be 
accordingly represented. Chapter 13 of EA-Pfahle contains information on the practical appli 
cation in the case of piles. 
3.I-2.3 Loading conditions, design situations and respective partial safety factors 
Impact combinations are attributed to geotechnical design situations according to DIN 1054. 
The design load values are determined in analogy to the DIBt guideline for wind turbines, with 
partial safety factors deviating from those mentioned in DIN 1054. 
The partial safety factors for impacts can be derived from the standards and guidelines for 
offshore wind turbines referred to in B3.3.1. The BSFI reserves the right to grant its consent. 
To assess the impacts of cyclic loads on the foundation elements, the characteristic impact 
loads normally have to be indicated. 
3-I.3 Cyclic loads on offshore platforms 
For any investigation of the influence of cyclic loads on the stability of the foundation elements 
of shallow foundations and special platform foundations similar to shallow foundations (e. g. 
suction caisson foundations), loads shall be calculated for a 100 year cycle. 
For deep foundations, the necessity of an explicit mathematical consideration of the cyclic 
loads in the verification control process can be assessed by means of a simplified marginal 
value analysis of the load range, resp. load amplitudes, according to the criteria described in 
EA-Pfahle. For this, the load shall be the maximum load induced by waves within a 50 year 
cycle (H max50 ). The action of the current shall be superimposed on this in an adverse fashion 
(possibly in opposite directions). If the explicit mathematical consideration of the cyclic loads 
is required for the verification control process, the decisive load spectrum shall be determined 
by means of a design storm. In the case of deep foundations, loads shall be calculated for a 
50 year cycle.