HiLo pile drivingKoen Hermans

ECN

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1. Introducing HiLo pile driving

2. Research goals

3. Results

Content

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HiLo pile drivingHigh frequency Low energy

• Minimize noise emissions

• Reduced fatigue damage

• Limited penalty on installation time

Introducing HiLo

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HiLo experiments

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HiLo project – goal

‘Develop a fatigue model, based on the experimental data, that can estimate the fatigue damage at the PDA location, using only the calendar data as an input.’

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HiLo project – model approach

Hammer Calendar- Energy/blow- Penetration

Plan penetration(driveability study)

Transferred- Energy- Force

Stresses in pile- Travelling wave

Fatigue- Stress cycle- Damage

Model

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Data available

Hammer Calendar- Energy/blow- Penetration- and many more...

Plan penetration(driveability study)

Transferred- velocity- Force

Stresses in pile- Travelling wave

Fatigue- Stress cycle- Damage

PDA: time series per blow

Calendar: per 0.25 m penetration

17 mei 2013 Titel 8

Results

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Results

Calendar energy [kJ]

Blow count [bl/25 cm]

Number of blows

Description Fatigue damage D

VP01 200-250 40 373 IHC recommended 0.0723 %

VP04 480-550 22 179 Industry standard 0.17 %

VP05 150-180 95 883 HiLo 0.0188 %

0

0,05

0,1

0,15

0,2

Fatigue damage [%]

IHC recommended Industry standard HiLo

-89 %

-74%

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Correlation methodology • i.e. model not directly applicable to other sites

• Calendar resolution is main source of error

Fatigue damage during installation was much smaller than expected• 0.17 % for conventional driving

• Stress concentration factor of 3.3 16 % damage (conventional driving)

Comparison piling strategies• Up to 89% reduction fatigue damage (‘HiLo’ vs ‘Conventional driving’)

Conclusion HiLo pile driving significantly lowers fatigue damage

Project results

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• Offshorewind.biz

• Cobouw

• Piledrivers magazine

• Deep Foundations magazine

News item

Koen HermansResearcher Support Structures, ECN

hermans@ecn.nl +31 625714364

Thanks for your attention

Questions?

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Concerning the low fatigue damage

Backup slide

• Stress concentrations cause a much higher damage• Up to 40 fold the fatigue damage for SCF = 3.3