28 
Part C - Minimum Requirements on geotechnical investigations 
Execution of cyclical tests and assessment therefore is not currently standardised. The labo 
ratories commissioned to carry out these investigations must have documented experience 
with cyclical tests. 
The type, number and boundary conditions of cyclical tests must be determined depending 
on the planned foundation. The number of cyclical loads and the size of the cyclical load level 
in the test must be chosen such that the test findings for the stated problem site are clear and 
provide comprehensive information. 
In this context, i.e. the liquefaction potential of in-situ soils may have to be analysed using 
suitable methods and taking into account the type of structure and load conditions if this is 
considered necessary by the geotechnical expert in co-ordination with the design engineer. 
A reliable and standardised concept for determining the liquefaction potential is not yet avail 
able. 
Information regarding cyclical tests is contained in e. g. Recommendations of the Soil Dynam 
ics working group of the DGGT - German Geotechnical Society (2002). Suitable test types 
along with their boundary conditions are listed to examine the influence of cyclical pressure 
changes on pile foundations in the EAP (2012), Chapter 13. Such recommendations do not 
yet exist for other foundation types such as heavy weight foundations or suction caissons. 
4 Geotechnical documents 
4.1 Preliminary remarks 
The findings of the geotechnical survey and investigation including assessments and recom 
mendations from the geotechnical expert are to be submitted in report format in the respec 
tive project phases or releases. In this case the geotechnical site survey report, which corre 
sponds to the geotechnical survey report in accordance with DIN EN 1997-2 and DIN 4020 
covers contents which are listed in Part C, Section 4.2. The soil and foundation expertise as 
sesses the findings of the geotechnical site survey report, gives recommendations for founda 
tions as well as implications for the structure and execution whilst containing characteristic 
values for ground conditions (see Part C, Section 4.3). 
The geotechnical site survey report and the soil and foundation expertise must be co-ordi 
nated and together form the geotechnical report in accordance with DIN 4020 (see DIN 
EN 1997-2, A7). A formal compilation of the geotechnical site survey report and the soil and 
foundation expertise is waived for the Federal Maritime and Hydrographic Agency. 
Both reports together form the basis for geotechnical planning and are also a component of 
the design basis which is to be drawn up or updated for the respective project phases. 
The geotechnical design development is the responsibility of a geotechnical planner (Fach- 
planer für Geotechnik) on behalf of the design engineer, who develops the geotechnical de 
sign of the foundation elements together with certificates of their structural safety and suita 
bility for use in a geotechnical design report in accordance with DIN EN 1997-1 (geotechnical 
planning contribution). The geotechnical design report includes the geotechnical site survey 
report and the soil and foundation expertise by reference. 
In accordance with DIN EN 1997-1,2.8 A note to (3), the geotechnical design report and geo 
technical report can be carried out by one person provided that they have the necessary 
knowledge and experience. The applicant or approval holder must ensure that the respective 
areas of responsibility are kept separate.