BIAXIAL BEHAVIOUR OF RC COLUMNS BUILT WITH PLAIN REBARS

Abstract

A considerable number of existing reinforced concrete (RC) buildings structures were designed before 80s, when the reinforcing bars had plain surface and prior to the enforcement of the modern seismic-oriented design codes. This paper presents the results of a recent experimental campaign performed on four full-scale RC columns representative of existing structures with plain reinforcing bars. The columns were tested under constant axial load and uniaxial or biaxial lateral cyclic loading until failure. An additional column, built with deformed reinforcing bars, was also tested. All specimens have square cross-section (30x30cm) and represent a cantilever with 1.5m of span. The main experimental results are presented and discussed. The influence of bond properties on the column behaviour is evidenced by differences observed between the cyclic response of similar specimens with plain and deformed bars. The effect of the lateral loading path on RC columns built with plain bars is also presented. (c) 2024, International Association for Earthquake Engineering. All rights reserved.