Offshore Pile Testing Campaign Wikinger

Transcription

1 Offshore Pile Testing Campaign Wikinger Pile driving analysis, static and dynamic load tests in 40m water depth Jan Fischer, Fichtner Water & Wind GmbH, Hamburg, Germany Rob van Dorp, Allnamics BV, Den Haag, The Netherlands

2 Wikinger OWF Developer Iberdrola Renewables Deutschland GmbH The Windfarm Turbine: 70 Adwen AD (5 MW, Rotor-, 135 m) Project Capacity: 350MW Foundation: Jackets Water depth: 36 m to 42 m Pile testing campaign Execution: Bilfinger Marine & Offshore Systems GmbH Date: 2014/2015 Installation Company: Boskalis and Volker Stevin Start: spring 2016 Slide 2

3 Location Slide 3

4 Pile testing campaign General Only very little information exists about the skin friction and toe resistance behavior of typical Baltic Sea soils as glacial till and chalk. Why Gain soil data information for driveability studies and for bearing capacity calculations How Extensive offshore pile testing campaign including pile driving analysis (PDA), dynamic load tests (DLT) and pull out static load tests (SLT-T) Source: ECSMGE 2015, Barbosa et al. Special Task: Testing underwater, in depths of approx. 40 m Slide 4

5 Fichtner / Allnamics Drivability predictions / hammer selection Producing the deep sea operation sensors, cables etc. (for PDA and DLT) Development of method statements for the different investigation phases Pile driving analysis / dynamic load tests (at altogether six piles) Signal matching (using AllWave-DLT) Back calculation (simulation) of the pile driving using the results from the pile driving protocols and the dynamic load tests Execution of the static tension pull out test (SLT-T) in terms of correct application of the different load steps Interpretation of the static tension pull out test Restrike dynamic load tests including signal matching Interpretation of the soil setup on the basis of the results from the different phases etc. Slide 5

6 Phase I Installation of nine piles at three different locations, including pile driving analysis (PDA) and dynamic load testing (DLT) Test piles: Location Water depth [m MSL] Diameter [m] Pile length [m] Penetration depth at the end of driving [m BSF] WK-a WK-b WK-c MV Lone: DP2 Vessel by SAL Slide 6

7 Phase I - Equipment Triplex Template (Pile guiding frame) Pile Hammer (MENCK MHU 800S) Slide 7

8 Phase I - Video Slide 8

9 Instrumentation and testing Two equipped test piles per location (for SLT and DLT) Two separate sets per pile Each set consisting of two strain transducers and two acceleration transducers Each 'pair' (strain and acceleration) placed diametrically opposed on the pile shaft Special deep sea sensors and cables Data recorder (PDR) Instrumentation Slide 9

10 Phase II - Equipment Phase II: Execution of one static tension pull out test (SLT-T) and one dynamic re-strike test (DLT) per test location. More than ten weeks after pile installation as part of Phase I Reference frame (SLT-T) Displacement measurement Loading beam (SLT-T) Force application Hammer (DLT) Slide 10

11 Phase II - Video Slide 11

12 Phase II SLT-T Loading Beam and Reference Frame Locking Tool Slide 12 page 12

13 Phase II SLT-T Slide 13 page 13

14 normalized displacement [-] normalized force [-] normalized force [-] Phase II Results Statische Probebelastung Load-Displacement normalized Force [-] Static tension pull out test (SLT-T) DLT restrike Allnamics strain gauges (mean value) Strain Load cells transducer (cumulative 1 value) Strain transducer 2 Acceleration trancducer 1 (v*z) Accerleration trancducer 2 (v*z) normalized time [-] time [ms] Restrike dynamic load test Slide 14

15 Summary The entire offshore testing campaign can be considered a huge success, especially since tests of this nature had not been performed before During the execution of the work in Phase I and Phase II, all tests could be carried out with high accuracy and high quality data The obtained test results led to a detailed understanding of the skin friction and toe resistance values for large diameter offshore pipe piles in typical Baltic Sea soils, i.e. glacial till and chalk What is next On the basis of the obtained test results, the installation of the wind turbine piles was predicted by us The results were used e.g. for pile driving fatigue calculations, as an important value for the pile design Slide 15

16 Thank you for your attention FICHTNER WATER & WIND Fichtner Water & Wind GmbH Hammerbrookstrasse 47b D Hamburg Tel jan.fischer@fww.fichtner.de FICHTNER WATER & WIND Allnamics BV Waterpas 98 NL-2495 Den Haag Tel. +31 (0) vandorp@allnamics.eu