Jonas Cramer

Jonas Cramer, M.Sc.

Fachgebiet Massivbau

Beethovenstraße 52

38106 Braunschweig

Telephone: 0531/391-5416

Research project:

Local investigations of crack width development under service loads

The prevention of cracks in reinforced concrete construction is usually neither possible nor reasonable. In order to ensure corrosion protection of the reinforcement, tightness and good appearance in reinforced concrete (RC) members, however, crack widths must be limited to a certain extent. For a realistic calculation of the crack widths a multitude of influencing parameters has to be considered. In particular, long-term effects such as changing loading conditions during the service life of a RC member and the nonlinear material behaviour (e.g. bond creep, concrete creep and concrete shrinkage) should be considered.

Within the research project, crack width is to be investigated theoretically, experimentally and numerically, taking into account long-term effects. In particular, the load path dependent slip between the reinforcement and the surrounding concrete, the internal crack formation in the area of the reinforcement (secondary cracks or Goto cracks) and the crack width profile of primary cracks from the reinforcement bar to the RC member surface should be considered. The aim of the planned investigations is the quantification and consideration of local damage effects for determination of crack widths. The results are expected to provide important findings on effects that are considered globally or merely in a simplified way, as well as on the influence of changing loading conditions during the service life (load path dependency) in the calculation of crack widths.

Jonas Cramer
Photo credit: Jonas Cramer/Alle Rechte bei der TU Braunschweig

Publications within the framework of the RTG:

Publications in peer-reviewed scientific journals:

M. Empelmann and J. Cramer. Modell zur Beschreibung der zeitabhängigen Rissbreitenentwicklung in Stahlbetonbauteilen. Beton- und Stahlbetonbau 114, Heft 5, S. 327-336, 2019.

Conference contribution with publication in conference proceedings:

M. Empelmann and J. Cramer. Besondere Aspekte bei der Rissbreitenberechnung - Empfehlungen für die Praxis. Betonwerk + Fertigteil-Technik (BFT) International (2019), Heft 2, S. 87.

M. Empelmann, V. Oettel and J. Cramer. Crack widths in steel fibre concrete members with conventional reinforcement. Derkowski, W. et al. (Ed.): Proceedings of the fib Symposium 2019, S. 335-342, Krakau (Polen), 27.-29.05.2019.

M. Empelmann and J. Cramer. Time-dependent development of crack widths in reinforced concrete structures. Derkowski, W. et al. (Ed.): Proceedings of the fib Symposium 2019, S. 621-628, , Krakau (Polen), 27.-29.05.2019.

Additional literature:

M. Empelmann and J. Cramer. Rissbreiten an biegebeanspruchten Bauteilen. Beton- und Stahlbetonbau 113, Heft 4, S. 291-297, 2018.

M. Empelmann, O. Fischer, J. Cramer and M. Henke. Bauteile unter Normalkraft nach Theorie II. Ordnung. DAfStb-Heft 630 - Bemessung nach DIN EN 1992 in den Grenzzuständen der Tragfähigkeit und der Gebrauchstauglichkeit, S. 61-86, Beuth Verlag, Berlin, 2018.

M. Empelmann and J. Cramer. Begrenzung der Rissbreiten. DAfStb-Heft 630 - Bemessung nach DIN EN 1992 in den Grenzzuständen der Tragfähigkeit und der Gebrauchstauglichkeit, S. 87-103, Beuth Verlag, Berlin, 2018.

J. Schnell, M. Empelmann, V. Oettel and J. Cramer. Praxisgerechtes Konstruieren und Bewehren am Beispiel. Stahlbetonbau - Beispiele aus Bemessung, Konstruktion, Planung und Ausführung, Berlin: Beuth Verlag, 2016.

M. Empelmann and W. Krakowski. Erweitertes Modell zur Berechnung der Rissbreite. Beton- und Stahlbetonbau 110, Heft 7, S. 458-467, 2015.

M. Empelmann. Zum nichtlinearen Trag- und Verformungsverhalten von Stabtragwerken aus Konstruktionsbeton unter besonderer Berücksichtigung von Betriebsbeanspruchungen. Institut für Massivbau, RWTH Aachen, Heft 2, 1995.