A simple procedure is proposed for the assessment of reinforced rectangular concrete columns under combined biaxial bending and axial loads and for the design of a correct amount of FRP-strengthening for underdesigned concrete sections. Approximate closed-form equations are developed based on the load contour method originally proposed by Bresler for reinforced concrete sections. The 3D failure surface is approximated along its contours, at a constant axial load, by means of equations given as the sum of the acting/resisting moment ratio in the directions of principal axes of the sections, raised to a power depending on the axial load, the steel reinforcement ratio, and the section shape. The method is extended to FRP-strengthened sections. Moreover, to make it possible to apply the load contour method in a more practical way, simple closed-form equations are developed for rectangular reinforced concrete sections with a two-way steel reinforcement and FRP strengthenings on each side. A comparison between the approach proposed and the fiber method (which is considered exact) shows that the simplified equations correctly represent the section interaction diagram.

Alessandri, S., G., M. (2008). Design Equations for Assessment and FRP– Strengthening of Reinforced Concrete Rectangular Columns Under Combined Biaxial Bending and Axial Load. MECHANICS OF COMPOSITE MATERIALS, 3, 309-322 [10.1007/s11029-008-9022-0].

Design Equations for Assessment and FRP– Strengthening of Reinforced Concrete Rectangular Columns Under Combined Biaxial Bending and Axial Load

ALESSANDRI, SILVIA
;
2008-01-01

Abstract

A simple procedure is proposed for the assessment of reinforced rectangular concrete columns under combined biaxial bending and axial loads and for the design of a correct amount of FRP-strengthening for underdesigned concrete sections. Approximate closed-form equations are developed based on the load contour method originally proposed by Bresler for reinforced concrete sections. The 3D failure surface is approximated along its contours, at a constant axial load, by means of equations given as the sum of the acting/resisting moment ratio in the directions of principal axes of the sections, raised to a power depending on the axial load, the steel reinforcement ratio, and the section shape. The method is extended to FRP-strengthened sections. Moreover, to make it possible to apply the load contour method in a more practical way, simple closed-form equations are developed for rectangular reinforced concrete sections with a two-way steel reinforcement and FRP strengthenings on each side. A comparison between the approach proposed and the fiber method (which is considered exact) shows that the simplified equations correctly represent the section interaction diagram.
2008
Alessandri, S., G., M. (2008). Design Equations for Assessment and FRP– Strengthening of Reinforced Concrete Rectangular Columns Under Combined Biaxial Bending and Axial Load. MECHANICS OF COMPOSITE MATERIALS, 3, 309-322 [10.1007/s11029-008-9022-0].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/186844
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