Fatigue of R-UHPFRC members and monitoring of fatigue actions effects

The service duration of structures like reinforced concrete bridges and wind turbines depends on the fatigue behaviour and fatigue strength of structural components. In order to realistically evaluate the fatigue safety of these structures by engineering methods, precise data regarding the fatigue action effect (characteristics, amplitude) due to traffic loading and wind respectively are needed. Those data can be obtained by long-term monitoring of existing structures. In addition, knowledge about the fatigue behaviour of reinforced concrete needs to be improved and novel engineering methods for realistic fatigue safety verification shall be proposed. Novel cementitious materials like Ultra-High Performance Fibre Reinforced cement-based Composites (UHPFRC) shall be investigated to explore ways to build the next generation bridges and wind turbines as well as to improve existing structures.

Keywords: monitoring, fatigue, UHPFRC, reinforced concrete, bridges and wind turbine towers.
Research fields: structural engineering, cement-based materials, fatigue of reinforced concrete and UHPFRC, 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)

48 months
From 01.01.2017 to 31.12.2021

The objective is to investigate the fatigue behaviour of structural elements in reinforced concrete of bridges and wind turbines including novel cementitious materials like Ultra-High Performance Fibre Reinforced Cementitious Composite (UHPFRC). Relevant fatigue prone structural elements usually are bridge deck slabs and short span bridge elements as well as foundations and towers of wind turbines. Novel methods for the design of new structures and for the examination of existing structures and their elements shall be developed. The research findings will provide the necessary knowledge for establishing a novel engineering approach based on monitoring by inspections or continuous measurements cross-validating fatigue damage model for concrete and UHPFRC including stochastic aspects. This will allow determining the fatigue safety in a reliable way optimising thus cost of transportation and energy production infrastructures.

The project has the following objectives:

  • Analysis and interpretation of data from long-term monitoring (continuous in-situ measurements) of multiple bridges to deduce a model describing the fatigue action effect.
  • Experimental investigation of the fatigue behaviour of reinforced UHPFRC.
  • Validation of the findings by means of case studies.
  • Thorough literature review to identify and define an experimental campaign to investigate the fatigue behaviour of reinforced concrete and/or UHPFRC (which is a novel cementitious building material having the potential to build structures with higher performance in terms of fatigue and life-cycle costs)
  • Based on the results of the experimental campaign and monitoring data, develop analytical engineering methods for the determination of fatigue strength (and possibly the fatigue endurance limit)
  • Develop a novel fatigue damage model for concrete and UHPFRC including stochastic aspects
  • Validate the concrete fatigue damage model in view of its implementation and application for the fatigue safety verification within the design and examination of fatigue relevant structural elements in reinforced concrete and UHPFRC
  • Novel and validated engineering methods for the fatigue design of new structures and for the fatigue examination of existing structures (bridges and components of wind turbines) based on data from monitoring.
  • 3 accepted peer-reviewed papers
  • Successfully defended PhD thesis
  • AAU (Aalborg, Denmark)
    August & September 2017
    Establish basis and develop a methodology for stochastic modelling of physical and model uncertainties for fatigue of concrete using a probabilistic approach.
  • EIFFAGE (Vélizy-Villacoublay, France)
    July to September 2019
    Design and construction of structures in UHPFRC.

There are a series of easy to access papers on:

  • The fatigue behaviour and fatigue strength of reinforced concrete as well as UHPFRC.
  • Structural health monitoring.
  • Fatigue and reliability of structures like bridges and wind turbines.

Publications

Outreach activities

ESR5 Bartek Sawicki:

Contact

Contact

ESR 5: Bartek Sawicki (EPFL)

bartek.sawicki@epfl.ch

Contact

Local academic supervisor: Prof. Eugen Brühwiler (EPFL)

eugen.bruehwiler@epfl.ch

Contact

Industrial co-supervisor: Christian Clergue (EIFFAGE)

christian.clergue@eiffage.com