Secondary Effects of Prestressing at ULS on Hyperstatic Structures

Abstract:

Secondary (parasitic) effects of prestressing develop in hyperstatic structures (continuous beams) due to restraining of imposed deformation by hyperstatic restraints. These effects may, in some case, significantly influence internal forces and stresses in prestressed structures. Internal forces due to the secondary effects should be included in design combinations for verification of both ultimate and serviceability limit state. Because secondary effects are influenced by structural system, there is a question how they will change after changing of the structural system e.g. due to development of plastic hinge (s) in a critical cross-section (s) or after development of kinematic mechanismThis article describes an experimental program at Slovak University of Technology in Bratislava, Department of concrete structures and bridges and its results. Program were focused on investigation of behavior of continuous post-tensioned beams with significant secondary effects of prestressing subjected to ultimate load. Together six, two span beams were tested, with maximum load changing structural system into kinematic mechanism. Secondary effects of prestressing were detected by measurement of reactions in all supports, further there were measured displacements in the quarters of both spans and strains in critical sections of the beams.

• Periodical: Key Engineering Materials (Volume 691)
• Pages: 138-147
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.691.138
• Online since: May 2016
• Authors: Peter Pažma*, Viktor Borzovič, Jaroslav Halvonik
• Keywords: Concrete, Kinematic Mechanism, Post-Tensioning, Secondary Effects of Prestressing, Statically Indeterminate Structure

References

[1] EN 1992-1-1 (2004) (English): Eurocode 2: Design of concrete structures - Part 1-1: General rules and rules for buildings [Authority: The European Union Per Regulation 305/2011, Directive 98/34/EC, Directive 2004/18/EC].

[2] NAVRÁTIL, Jaroslav. Prestressed concrete structures. 2nd ed. Ostrava: Technical University of Ostrava, Faculty of Civil Engineering, 2014, 220 s. ISBN 978-80-248-3625-6.

[3] Moravčík, M. - Dolinajová, K. - Kucharík, J.: Some experiences from the long-term monitoring on bridges realised by free cantilever method. The Fourth International fib Congress 2014, Mumbai, Improving Performance of Concrete Structures, Proceedings (Summary Papers Vol. II), Organised by: IMC-fib of The Institution of Engineers (India), ISBN 978 81 7371 919 6, 661-664.