NDT parameters for fatigue damage identification in structural elements

The service duration of structures like reinforced concrete bridges and wind turbines depends on the fatigue of structural components due to respectively traffic loading and wind action. In order to realistically evaluate fatigue damage, Non-Destructive Testing methods would be a real asset. In this project, ultrasonic sensor networks shall be used to detect and monitor fatigue damage in reinforced concrete of bridges subjected to traffic induced fatigue loading. Fatigue damage may be identified and analysed from microcracking in the bulk concrete material due to fatigue cracking in steel reinforcing bars that are usually the determinant fatigue vulnerable element in reinforced concrete. Fatigue damage determined from NDT shall be related to fatigue action effects.

Keywords: Non-Destructive Testing, ultrasonic methods, monitoring, reinforced concrete, fatigue.
Research fields: Non-Destructive Testing, wave methods, fatigue of reinforced concrete, structural health monitoring.

EPFL (Lausanne, Switzerland)
Swiss Federal Institute of Technology

EPFL - ENAC, School of Architecture, Civil and Environmental Engineering (Lausanne, Swizterland)

PhD director: Prof. Eugen Brühwiler (EPFL)

36 months
From 01.02.2017 to 31.01.2020

The general objective is to correlate NDT parameters (e.g. ultrasonic velocity, attenuation, fibre optic) to fatigue related phenomena and parameters to identify any fatigue damaging process (i.e. the formation of microcracks in concrete, slow microcrack propagation in steel elements) in structural elements and components at the earliest possible stage.

Novel ways to analyse ultrasonic data in terms of damage shall be developed and imaging techniques shall be extended to structural field applications. This includes lab investigations using ultrasonic, acoustic emission methods and fibre optic in the laboratory to measure microcrack formation in materials due to fatigue, numerical simulation of observed phenomena on the micro level of material behaviour to investigate the existence of a fatigue endurance limit and application of the developed technology on an existing wind turbine tower and bridge deck slab at the most fatigue prone zones.

  • Laboratory testing using ultrasonic, acoustic emission and fibre optic methods to measure microcrack formation in materials (concrete, steel rebars) due to fatigue.
  • Numerical simulation of observed phenomena on the micro level of material behaviour to investigate the existence of a fatigue endurance limit.
  • Application of the developed technology on an existing wind turbine tower and bridge deck slab at the most fatigue prone zones.
  • Novel NDT methodology validated and applicable for the fatigue damage monitoring on structural elements and components of bridges and wind turbine towers.
  • Implementation at a real structure.
  • 3 accepted peer-reviewed papers.
  • Successfully defended PhD thesis.
  • BAM (Berlin, Germany)
    August & September 2017
    NDT: ultrasound and acoustic emission methods
  • AAU (Aalborg, Denmark)
    April to June 2018
    Reliability analysis
  • NeoStrain (Krakow, Poland)
    April to May 2019
    Structural Health Monitoring

There are a series of easy to access papers on:

  • The fatigue behaviour of concrete and steel rebars.
  • Ultrasonic testing methods to detect microcracking.

Publications

  • Bayane I., Mankar A., Brühwiler E., Sørensen J.D.
    Quantification of traffic and temperature effects on the fatigue safety of a reinforced-concrete bridge deck based on monitoring data
    Submitted to Engineering Structures
  • Mankar A., Bayane I., Sørensen J.D., Brühwiler E.
    Probabilistic reliability framework for assessment of concrete fatigue of existing RC bridge deck slabs using data from monitoring
    Submitted to Engineering Structures Journal, 2019

Outreach activities

ESR4 Imane Bayane:

Contact

Contact

ESR4: Imane Bayane (EPFL)

imane.bayane@epfl.ch

Contact

Local academic supervisor: Prof. Eugen Brühwiler (EPFL)

eugen.bruehwiler@epfl.ch

Contact

Industrial co-supervisor: Dr Piotr Klikowicz (NeoStrain)

piotr.klikowicz@neostrain.pl