Experimental tests and numerical study of RC beams strengthened with external tendons / Szymon Seręga, Dariusz Henryk Faustmann // W: Concrete – innovations in materials, design and structures : proceedings ... więcej

Experimental tests and numerical study of RC beams strengthened with external tendons / Szymon Seręga, Dariusz Henryk Faustmann // W: Concrete – innovations in materials, design and structures : proceedings of the fib Symposium 2019 held in Kraków, Poland 27-29 May 2019 [Dokument elektroniczny] / eds. W. Derkowski, P. Gwoździewicz, Ł. Hojdys, P. Krajewski, M. Pańtak. – [Kraków] : International Federation for Structural Concrete, 2019. – Pamięć USB. – (fib Symposium Proceedings, ISSN 2617-4820). – S. 1555-1562 : rys., tab., wykr. – Bibliogr. s. 1562, Abstr. – Nazwa wydawcy wg cop. – ISBN 978-2-940643-00-4

The paper presents experimental tests and a parametric study of RC beams strengthened with prestressed external tendons. Three beams were tested in the experimental part of the research. All beams were ... więcej

The paper presents experimental tests and a parametric study of RC beams strengthened with prestressed external tendons. Three beams were tested in the experimental part of the research. All beams were initially preloaded before strengthening. Two different schemes of loading and prestressing force were considered. For the scheme 1 the RC beam was unloaded during prestressing whereas for the scheme 2 the external load was maintained constant during prestressing process. The experimental results show that the effect of unloading before prestressing has negligible influence on load bearing capacity of the tested specimens. A three-dimensional (3D) numerical model was worked out and presented in the paper. The numerical analyses consisted of the set of phases to reflect the loading stages performed in the experimental part of the research. The following variables were analysed in the parametric study: initial prestressing force for scheme 1 and concrete class for scheme 2.The numerical models correctly reproduced the failure modes observed in the experiments. A very good agreement between the experimental tests and numerical simulations were obtained. Numerical model correctly reflects cracks patterns, load-displacement behaviour and stress increase in tendons during the second phase of loading. The parametric study shows that for unloaded specimens the initial prestressing force has moderate influence on load bearing capacity and load - displacement behaviour. The effect of concrete class is more important as the failure mechanism is governed by concrete crushing in the compressive zone of the beam.