Immediate and time-dependant behavior of RC columns strengthened by high-performance concrete jackets / Comportamento resistente imediato e ao longo do tempo de pilares reforçados por meio de encamisamento com concreto de alto desempenho

AUTOR(ES)

Adilson Roberto Takeuti

DATA DE PUBLICAÇÃO

2003

RESUMO

The thesis presents an experimental investigation on the behavior of RC columns strengthened by high-performance concrete jackets. The main objectives are to analyze the immediate and time-dependant behavior of the elements and the preloading effect in its load capacity and deformability. Twenty columns were tested varying the transversal section shape (circular and square), transversal reinforcement ratio of the jacket and the preloading condition. Also complimentary tests were made on short circular section columns to observe confinement effects. A set of long-term tests was made to characterize the concrete immediate and time-dependant properties. To analyze the influence of time-dependant deformations, original columns were submitted to preloading forces and they were kept in a weather-controlled chamber during a certain period. The high-performance concrete jackets were applied to the original columns without removing the preloading forces. Every column was subjected to a monotonic axial compression test in a servohydraulic universal machine, in the displacement-controlled mode. In the analysis of the results theoretical models of concrete confinement, Finite Element Method simulations and other formulations were applied to examine the experimental results. The main conclusions are that, if adequate confinement conditions are maintained in the strengthened columns: the load capacity of the original column can be totally considered in strength evaluation; the preloading effect does not affect the ultimate load of the rehabilitated member, but it may affect the column deformability. Moreover, in the long-term behavior analysis, load transfer between the original column and jacket was observed. However, its effect was not significant in the load capacity of the strengthened member

ASSUNTO(S)

high-performance concrete columns pilares retração strengthening fluência creep reforço concreto de alto desempenho shrinkage

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