N-M AND M-K RELATIONSHIPS OF REINFORCED CONCRETE COLUMNS IN TEC2018

Year 2018, Volume: 19 Issue: 2, 499 - 513, 30.06.2018

Ayten Günaydın Hande Gökdemir

https://doi.org/10.18038/aubtda.402180

Abstract

Reinforced concrete
elements subject to moment, shear and axial force due to different level of
static and dynamic loads based on their location and material characteristics.
These elements disseminate the loads based on their connections with other
elements. In particular, each column in the structure exhibits "combined
bending" behavior together with the resulting moment of the eccentric
axial force exerted. In the case of the axial load acting on one of the
symmetry axes (x or y axis) the uniaxial bending, and the axial load acting out
of the symmetry axis, biaxial bending occurs. Also, since the structures are
composed of two directional frames and slabs, the reinforced concrete columns
are subject to combined bending effects in both directions. Therefore, the
determination of the ultimate strength and behavior of the reinforced concrete
columns depends on the interaction of axial force (N) and moment (M). In this
study, the N-M diagram of reinforced concrete columns is given considering the
section geometry, concrete and steel reinforcement strength and placement of
the longitudinal reinforcements. The given N-M diagrams are prepared based on
the axial force limits in codes. In addition, the N-e diagram showing the axial
force and eccentricity relation of reinforced concrete column sections is
given. Ductility ratios are given by plotting the moment curvature diagrams of
the column sections at various axial force levels of the N-M diagram.

Keywords

N-M interaction diagram, axial force, eccentricity, bending moment-curvature diagram

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