DBPapers
DOI: 10.5593/SGEM2014/B62/S27.079

SHEAR STRESSES TRANSFER AT THE STEEL-CONCRETE INTERFACE IN CIRCULAR CONCRETE FILLED STEEL TUBES

C. Moga, S. I. Gutiu, A. D. Danciu
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-21-6 / ISSN 1314-2704, June 19-25, 2014, Book 6, Vol. 2, 613-620 pp

ABSTRACT
The concrete filled steel tubes, also known as CFT, have, as a main advantage over the reinforced concrete system, the fact that the interaction between the steel tube and the concrete improves the buckling behaviour of the steel tube and increases the strength of the concrete. This paper presents the research done by the authors in understanding the mechanism of the shear transfer over the interface between the circular steel tube and the concrete core. Shear stresses appear due to the action of the shear forces over the element crosssection. According to the shear stresses duality, longitudinal shear arises along the length of the element (column), that tend to produce the relative slipping between the concrete and the steel tube. While the tangential tensile stresses do not exceed a certain size, the adhesion, the friction and the surface irregularities are sufficient. If the tensile stresses grow, it becomes necessary to use mechanical connectors. The paper presents a methodology for finding the bond-slip at the interface of the steelconcrete for CFT, followed by a proposed design methodology. Using the proposed methodology the authors investigated the longitudinal shear stress over the interface between a circular steel tube and the concrete core for different values of the crosssection of the circular steel tube.

Keywords: Concrete filled steel tubes (CFT), steel-concrete composite structures,
bond-slip behaviour.