In this paper the behaviour in compression and in flexure of RC members externally strengthened with concrete jacketing is analysed. A fibre model was utilized to predict the moment-curvature diagrams of the strengthened members on the basis of stress-strain curves of the constituent materials (confined concrete, steel bars). The stress-strain curves in compression for concrete were able to take into account the confinement effects induced by pre-existing internal stirrups and additional steel reinforcements of concrete jacketing. The stress-strain laws in compression of the longitudinal bars adopted include the second-order effects. A preliminary validation of the model adopted was made referring to the experimental data available in the literature on the compressive behaviour of RC columns strengthened with concrete jacketing. Then cases of members under axial force and bending moment were analysed. Good agreement was obtained with the available data in terms of moment-axial force domains and moment-curvature diagrams. The analysis showed the effectiveness of this reinforcing technique in improving both the strength and the ductility of RC columns, highlighting the importance of an accurate choice of strengthened materials (concrete grade, thickness of jacket, space and diameter of stirrups, etc).

Comportamento in pressoflessione di pilastri in c.a. rinforzati con la tecnica dell’incamiciatura leggera

FOSSETTI, MARINELLA;
2012

Abstract

In this paper the behaviour in compression and in flexure of RC members externally strengthened with concrete jacketing is analysed. A fibre model was utilized to predict the moment-curvature diagrams of the strengthened members on the basis of stress-strain curves of the constituent materials (confined concrete, steel bars). The stress-strain curves in compression for concrete were able to take into account the confinement effects induced by pre-existing internal stirrups and additional steel reinforcements of concrete jacketing. The stress-strain laws in compression of the longitudinal bars adopted include the second-order effects. A preliminary validation of the model adopted was made referring to the experimental data available in the literature on the compressive behaviour of RC columns strengthened with concrete jacketing. Then cases of members under axial force and bending moment were analysed. Good agreement was obtained with the available data in terms of moment-axial force domains and moment-curvature diagrams. The analysis showed the effectiveness of this reinforcing technique in improving both the strength and the ductility of RC columns, highlighting the importance of an accurate choice of strengthened materials (concrete grade, thickness of jacket, space and diameter of stirrups, etc).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11387/18725
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