Linear and Non-Linear Cyclic-Creep of Concrete with defined Moisture Contents
Final Report Abstract
Long-term deformations of concrete structures are described by creep models that were developed from constant exposures. In practice, constant creep loads are superimposed by cyclic exposures. Measurements on existing reinforced and prestressed concrete bridges let assume that the long-term deformations might exceed the predicted deformations due to cyclic mechanical and climatic exposures. An underestimation of deformations occurring in practice can lead to damage and safety risks. Therefore, the aim of the joint project was to investigate the effects of cyclic-mechanical and cyclic-hygric exposures on the long-term deformation of concrete. Within the framework of this sub-project, which is focusing only on the cyclic-mechanical loading, significant increases in long-term strains were measured compared to those at a constant load at mean stress level. Instead the cyclic strains are closer to and also partly exceed the creep strains due to constant maximum stress level. This is attributed to different degradation processes in the microstructure of the concrete, which leads to changes in the macroscopic concrete properties. It is therefore necessary to consider varying load scenarios and moisture contents, when predicting the long-term deformations of concrete structures. First considerations for an extended prognosis model are discussed.
Publications
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Comparative analysis of concrete behaviour under compressive creep and cyclic loading. International Journal of Fatigue, 153, 106409.
Kern, Bianca; Oneschkow, Nadja; Podhajecky, Anna-Lena; Lohaus, Ludger; Anders, Steffen & Haist, Michael
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Comparison of long-term strain development of concrete due to creep and cyclic loading, The Biot-Bazant Conference
Kern, B.; Oneschkow, N.; Haist, M. & Lohaus, L.
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Long-term strain development of concrete subjected to creep and cyclic loading, Proceedings of the 2021 session of the 13th fib International PhD Symposium in Civil Engineering, Paris, France, 21-22 July, 2021, pp. 251-257; ISBN: 978-2-940643-11-0
Kern, B.; Oneschkow, N.; Lohaus, L. & Haist, M.
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Influence of moisture content on strain development of concrete subjected to compressive creep and cyclic loading. Current Perspectives and New Directions in Mechanics, Modelling and Design of Structural Systems, 1357-1363.
Kern, B.; Oneschkow, N.; Haist, M. & Lohaus, L.
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Fatigue Damage Versus Creep Deformation – Differentiation Using The Development Of Stiffness. proceedings of the 11th International Conference on Fracture Mechanics of Concrete and Concrete Structures.
Weber, Fabian & Anders, Steffen
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Long‐term deformations of concrete under cyclic‐mechanical and cyclic‐hygric exposures. ce/papers, 6(6), 1061-1067.
Podhajecky, Anna‐Lena; Kern, Bianca; Oneschkow, Nadja; Lohaus, Ludger; Müller, Harald & Haist, Michael
