Comparison of predicted and measured pile driving processes at steel pipe piles in North and Baltic Seas

Foundation types of offshore wind turbines are mainly realised with steel pipe piles whereas most commonly
monopiles with large diameters or jacket piles are used. Against the background of cost effectiveness, the selection of
a driving system as well as design fatigue calculations it is of major importance to run driveability analyses prior to
the installation process. Essential criteria for that are the duration of a driving process and number of blows, pile
driving stresses in compression and tension and soil resistance to driving (SRD). While the application of SRD models
for impact driven piles in sand and clay is considered as well established a trusted prognosis of pile driving in other
soils or materials like chalk or the prognosis of vibratory pile driving is still a challenge.
At real pile driving usually dynamic pile driving monitoring is performed in order to record real blow counts and
stresses in the pile and furthermore, to verify pile capacity. In this paper driveability analyses and SRD models are
compared with results of dynamic pile tests and pile driving monitoring in selected offshore wind farm projects in the
North and Baltic Seas in order to check their applicability. Measurements were taken during the pile driving of small
and large diameter pipe piles in sand or chalk dominated soils by the use of impact and, partly, vibratory hammers.
Using appropriate wave equation software (GRLWEAP) driving processes could be recalculated and compared to
measured data and records of the driving system.