Deterioration of cracks in onshore wind turbine foundations

Research output: Contribution to journalArticle

Abstract

Cracks can occur in reinforced-concrete onshore wind turbine foundations due to factors such as the use of substandard concrete mix, mistakes in foundation design or multi-stage concrete pouring under challenging weather conditions. Cracks are routinely identified via above ground inspections and follow-on examination of excavated underground surfaces and are repaired, for example with resin injection and grouting. Their impact on the structure or the efficacy of the repair are often unknown as crack degradation during normal operating conditions is unexplored. In this work, sub-surface cracks in an onshore wind turbine foundation have been instrumented with fibre-optic based strain sensors in an attempt to determine severity and magnitude of deterioration over time. Here we determine cracks monitored show a small magnitude of deterioration over the initial 9-month period after sensor installation, suggesting that repair is not required. We propose a novel methodology for the classification of the types of deterioration evident in cracks as “reactive”, “permanent” and “behavioural”, and demonstrate methods to extract these types of deterioration. Such methods will continually be developed over time as further knowledge of crack behaviour is gained to determine appropriate limits and identify the optimal time to repair.
LanguageEnglish
Pages121-131
Number of pages11
JournalEngineering Structures
Volume167
Early online date12 May 2018
DOIs
StatePublished - 15 Jul 2018

Fingerprint

Wind turbines
Deterioration
Cracks
Repair
Grouting
Concrete mixtures
Sensors
Fiber optics
Reinforced concrete
Resins
Inspection
Concretes
Degradation

Keywords

  • cracks
  • foundations
  • degradation
  • fibre optic
  • strain
  • deterioration

Cite this

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title = "Deterioration of cracks in onshore wind turbine foundations",
abstract = "Cracks can occur in reinforced-concrete onshore wind turbine foundations due to factors such as the use of substandard concrete mix, mistakes in foundation design or multi-stage concrete pouring under challenging weather conditions. Cracks are routinely identified via above ground inspections and follow-on examination of excavated underground surfaces and are repaired, for example with resin injection and grouting. Their impact on the structure or the efficacy of the repair are often unknown as crack degradation during normal operating conditions is unexplored. In this work, sub-surface cracks in an onshore wind turbine foundation have been instrumented with fibre-optic based strain sensors in an attempt to determine severity and magnitude of deterioration over time. Here we determine cracks monitored show a small magnitude of deterioration over the initial 9-month period after sensor installation, suggesting that repair is not required. We propose a novel methodology for the classification of the types of deterioration evident in cracks as “reactive”, “permanent” and “behavioural”, and demonstrate methods to extract these types of deterioration. Such methods will continually be developed over time as further knowledge of crack behaviour is gained to determine appropriate limits and identify the optimal time to repair.",
keywords = "cracks, foundations, degradation, fibre optic, strain, deterioration",
author = "Jack McAlorum and Marcus Perry and Grzegorz Fusiek and Pawel Niewczas and Mckeeman, {Iain James} and Tim Rubert",
year = "2018",
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doi = "10.1016/j.engstruct.2018.04.003",
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AU - McAlorum,Jack

AU - Perry,Marcus

AU - Fusiek,Grzegorz

AU - Niewczas,Pawel

AU - Mckeeman,Iain James

AU - Rubert,Tim

PY - 2018/7/15

Y1 - 2018/7/15

N2 - Cracks can occur in reinforced-concrete onshore wind turbine foundations due to factors such as the use of substandard concrete mix, mistakes in foundation design or multi-stage concrete pouring under challenging weather conditions. Cracks are routinely identified via above ground inspections and follow-on examination of excavated underground surfaces and are repaired, for example with resin injection and grouting. Their impact on the structure or the efficacy of the repair are often unknown as crack degradation during normal operating conditions is unexplored. In this work, sub-surface cracks in an onshore wind turbine foundation have been instrumented with fibre-optic based strain sensors in an attempt to determine severity and magnitude of deterioration over time. Here we determine cracks monitored show a small magnitude of deterioration over the initial 9-month period after sensor installation, suggesting that repair is not required. We propose a novel methodology for the classification of the types of deterioration evident in cracks as “reactive”, “permanent” and “behavioural”, and demonstrate methods to extract these types of deterioration. Such methods will continually be developed over time as further knowledge of crack behaviour is gained to determine appropriate limits and identify the optimal time to repair.

AB - Cracks can occur in reinforced-concrete onshore wind turbine foundations due to factors such as the use of substandard concrete mix, mistakes in foundation design or multi-stage concrete pouring under challenging weather conditions. Cracks are routinely identified via above ground inspections and follow-on examination of excavated underground surfaces and are repaired, for example with resin injection and grouting. Their impact on the structure or the efficacy of the repair are often unknown as crack degradation during normal operating conditions is unexplored. In this work, sub-surface cracks in an onshore wind turbine foundation have been instrumented with fibre-optic based strain sensors in an attempt to determine severity and magnitude of deterioration over time. Here we determine cracks monitored show a small magnitude of deterioration over the initial 9-month period after sensor installation, suggesting that repair is not required. We propose a novel methodology for the classification of the types of deterioration evident in cracks as “reactive”, “permanent” and “behavioural”, and demonstrate methods to extract these types of deterioration. Such methods will continually be developed over time as further knowledge of crack behaviour is gained to determine appropriate limits and identify the optimal time to repair.

KW - cracks

KW - foundations

KW - degradation

KW - fibre optic

KW - strain

KW - deterioration

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