Jörn Remitz, M.Sc.
Fatigue of prestressed tendons
Prestressed concrete members with pre-tensioned tendons are used e.g. in crane runway beams, slabs in industrial constructions, towers of wind turbines, poles or bridges which are subjected to severe dynamic loads with high load cycles. These concrete members need to be designed against fatigue failure, while the fatigue of the prestressing steel is often the decisive failure mode.
Within previous research projects at the iBMB, Division of Concrete Construction a significant difference between fatigue tests with embedded pre-tensioned tendons in prestressed concrete members and tests with singular prestressing steel can be noticed especially at small stress ranges in the prestressing steel and high numbers of load cycles.
Within this research project the fundamentals of the fatigue behaviour of pre-tensioned tendons will be investigated experimentally, theoretically and numerically. Based on these investigations the different structural and systematical parameters and damage mechanisms are to be examined. These parameters are caused by the complex fatigue processes and stresses due to built-in conditions of pre-tensioned tendons and can lead to a significant reduction in the fatigue strength compared to fatigue tests on prestressing steel samples.
The aim of this project is to develop a model which describes the fatigue behaviour of prestressing steel including the effects of the various relevant parameters and damage mechanisms.
Bild1:
Comparison of test results of prestressed concrete girders with the fatigue strength curves according to EC2 and MC10 (left) as well as corrosion and wire break of a strand (right) (Source: see publications below)
Publications within the framework of the RTG:
Publications in peer-reviewed scientific journals:
J. Remitz and M. Empelmann. Ermüdungsfestigkeit von eingebauten Spanngliedern - Versuche an Spannbetonträgern. Bauingenieur 90 (2015), Heft 12, S. 553-561.
J. Remitz and M. Empelmann. Einfluss von Umlenkbelastungen auf die Ermüdung von Spanngliedern im nachträglichen Verbund. Beton- und Stahlbetonbau 113 (2018), Heft 8, S. 579-588.
Conference contribution with publication in conference proceedings:
J. Remitz and M. Empelmann. Ermüdungsnachweis der Bewehrung bei Spannbetonbauteilen. Seminarband zum VSVI-Seminar Nr. 10 "Brücken- und Ingenieurbau", S. 55-60, Braunschweig, 8. März 2016.
J. Remitz. Fatigue of Post-Tensioned Steel. Report of 4th IABSE Young Engineers Colloquium 2017, S.48-49, Bochum, 31.03.2017.
J. Remitz and M. Empelmann. Specific Influences on Fatigue Life of Prestressing Steel. In: Hiller, E. (Ed.): 12th Japanese German Bridge Symposium - Volume of Abstracts and Full Papers, München, 04.-07.09.2018.
J. Remitz and M. Empelmann. Fatigue Life of Curved Tendons in Post-Tensioned Concrete Structures. In: Foster, S. (Ed.): Proceedings of fib Congress 2018, 07.-11.10.2018 in Melbourne (Australien), S. 342-343 (abstract, full paper digital).
M. Empelmann and J. Remitz. Neue Ergebnisse zum Ermüdungsverhalten von Betonfertigteilen - Verhalten von vorgespannten Betonfertigteilträgern. Kongressunterlagen 63. BetonTage, 19.-21.02.2019 in Neu-Ulm, Betonwerk + Fertigteil-Technik (BFT) International (2019), Heft 2, S. 64.
Additional literature:
M. Empelmann and J. Remitz. Ermüdungsverhalten von Spanngliedern mit nachträglichem Verbund. Beton- und Stahlbetonbau 109, Heft 11, S. 760-770, 2014.
J. Remitz and M. Empelmann. Ermüdungsverhalten von eingebauten Spanngliedern. Seminarband zum VSVI-Seminar Nr. 12 "Brücken- und Ingenieurbau", Braunschweig, 2015.