Duration : 07.04.2010 – 06.04.2014
Supervisor : Professor Eugen Brühwiler
PhD student : Marina Rocha
In the last decades, with the occurrence of higher and more frequent axle loads, bridges are more significantly solicited by fatigue loading. In order to avoid costly interventions, there is a need to improve the methods for investigation of the fatigue safety of bridges. A reinforced concrete bridge deck can experience very high number of stress cycles, i.e. in the domain of more than 100 million cycles. Since the reinforcing steel dominates the fatigue behaviour of the reinforced concrete bridge elements, the S-N curves for rebars can be apply to assess the fatigue life. However, knowledge of the fatigue limit domain, i.e. very high number of cycles at relatively low stress ranges, is scarce and consequently, S-N curves in that domain are most likely conservative. This project has the objective to improve knowledge on the fatigue behaviour of steel reinforcing bars under very high cycle fatigue. For that purpose, fatigue testing will performed in the fatigue limit domain at very high number of cycles and the influence of the microstructure of steel on the fatigue behaviour of the rebars will be analysed.