THEORETICAL ANALYSIS OF BENDING OF CONCRETE BEAMS WITH CONFINED COMPRESSION AREA

Original Title: TEORIJSKA ANALIZA SAVIJANJA BETONSKIH GREDA S OVIJENIM TLAČNIM PODRUČJEM

Author: Tvrtko Renić, Tomislav Kišiček

DOI: https://doi.org/10.5592/CO/ZT.2021.15

First Page: 91   Last Page: 96

Abstract: Concrete beams reinforced with a large amount of tension steel reinforcement or with FRP reinforcement have low ductility which can be increased by confining the compression area. In this paper a theoretical explanation of ductility increase is given and procedure for defining bending moment – curvature diagrams for beams with confined compression area is described. Based on that diagram ductility of a section is easily determined, and by integration along the beam it is also possible to determine ductility of the element. This procedure enables the quantitative assessment of beam behaviour which simplifies the design process. Bending moments and curvatures of diagram are determined by considering force equilibrium, straight sections remaining straight and deformation compatibility. Confining the compression area can significantly increase the ductility of a section which is not acknowledged in current design standards. Additional research is needed to enable the use of such beams in practice.

Keywords: confined compression area, theoretical analysis, ductility

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