It is well known that if concrete members are confined by transverse steel and longitudinal bars, increases in the bearing capacity and in the corresponding strain are observed experimentally and confirmed theoretically by reduced lateral expansion of the concrete core. A number of stress-strain models and simplified formulae to predict maximum compressive strength and ultimate strain capacities of compressed concrete members confined by transverse steel have been presented in the past few decades. Moreover, in the past 15 years interest has also been addressed to the effect of confinement induced by transverse steel on concrete members made of high performance concretes, such as high strength of normal and lightweight type. These studies have focused attention on the principal parameters governing confinement in the concrete core highlighting the importance of: - concrete grade; - shape of the transverse cross-section of the members to be reinforced in relation to the type and grade of transverse and longitudinal steel (hoops, spirals, ties, jackets, etc.); - size of the specimens; - rate of loading; etc. Attention is here addressed to the case of high strength compressed concrete members having circular cross-section and confined by single hoops or steel spirals and longitudinal bars. An analytical model is given for calculation of the stress-strain curves of compressed members. The model is able to evaluate the confining pressure due to the steel hoops or steel spirals and to the longitudinal bars. The analytical results are then compared with experimental values given in the literature showing good agreement.

Simplified Analytical Model for Compressed High-Strength Columns Confined by Transverse Steel and Longitudinal Bars

FOSSETTI, MARINELLA;
2006

Abstract

It is well known that if concrete members are confined by transverse steel and longitudinal bars, increases in the bearing capacity and in the corresponding strain are observed experimentally and confirmed theoretically by reduced lateral expansion of the concrete core. A number of stress-strain models and simplified formulae to predict maximum compressive strength and ultimate strain capacities of compressed concrete members confined by transverse steel have been presented in the past few decades. Moreover, in the past 15 years interest has also been addressed to the effect of confinement induced by transverse steel on concrete members made of high performance concretes, such as high strength of normal and lightweight type. These studies have focused attention on the principal parameters governing confinement in the concrete core highlighting the importance of: - concrete grade; - shape of the transverse cross-section of the members to be reinforced in relation to the type and grade of transverse and longitudinal steel (hoops, spirals, ties, jackets, etc.); - size of the specimens; - rate of loading; etc. Attention is here addressed to the case of high strength compressed concrete members having circular cross-section and confined by single hoops or steel spirals and longitudinal bars. An analytical model is given for calculation of the stress-strain curves of compressed members. The model is able to evaluate the confining pressure due to the steel hoops or steel spirals and to the longitudinal bars. The analytical results are then compared with experimental values given in the literature showing good agreement.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11387/19546
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