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Gewählte Master / Diploma Thesis:

Verena Christine Schabus (2011): Stochastische dynamische Materialeigenschaften von Beton.
Master / Diploma Thesis - Institut für Konstruktiver Ingenieurbau (IKI), BOKU-Universität für Bodenkultur, pp 116. UB BOKU obvsg

Data Source: ZID Abstracts
The Thesis is dealing with changes in material parameters of concrete under dynamic loading, so called fatigue. It is commonly known that concrete endures higher compressive static loads than dynamic compressive loads, e.g. dynamic compressive strength of concrete is set 45% of its static strength and it is depending on the dynamic load number described in the S-N curve (in German: Wöhler line). Up to now the behaviour of the material components is not fully revealed. In this study cyclic loading was applied on small specimen using Ultrasonic frequencies to cause fatigue damages. This method has not been used for concrete yet. The advantages lie within the short testing time. In fact the aim is to find fatigue parameters that shall be measurable by non-destructive methods. As a result deterioration in the material can be described. The application of ultrasonic fatigue testing equipment has to be tested during a pre-study. Additionally to ultrasonic fatigue tests low-frequency tests (according to international research tests) were conducted to establish comparability. The results confirm studies that criticise the currently used formulation of S-N-Curves as too conservative. It is found that ultrasonic fatigue testing equipment can be used for concrete tests. The compared parameters (resonance frequency and remaining compressive strength) show comparable results of both methods. Besides indicators for damages (resonance frequency and stress-strain relation) are described. The results of this study can be seen as a contribution for a research project in concrete fatigue assessment. The project aims on developing a system for integration of monitoring data into design codes in order to estimate the remaining lifetime of concrete foundations of Offshore Wind Parks.

Beurteilende(r): Strauss Alfred

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