Behaviour of reinforced self-consolidating concrete frames

Abstract

Multi-storey reinforced concrete (RC) structural frames represent some of the most congested structural elements. Placing and consolidating concrete in such structural frames imposes substantial challenges. This offers a unique area of application for self-consolidating concrete (SCC) because of its inherent ability to flow under its own weight and fill congested sections, complicated formwork and hard-to-reach areas. Research is, however, needed to demonstrate the ability of SCC structural frames adequately to resist vertical and lateral loads. In the present study, full-scale 3 m high beam-column joints reinforced as per the Canadian Standards CSA A23·3-94 and ACI-352R-02 were made with normal concrete (NC) and SCC. They were tested under reversed cyclic loading applied at the beam tip and at a constant axial load applied on the column. The beam–column joint specimens were instrumented with linear variable displacement transducers and strain gauges to determine load–displacement traces, cumulative dissipated energy and secant stiffness. The current paper compares the performance of reinforced NC and SCC structural frames and discusses the potential use of SCC in such structural elements. Results indicate that reducing the coarse aggregate content in SCC mixtures can reduce the contribution of the aggregate interlock mechanism to total shear resistance, which leads to more rapid deterioration under cyclic loading. Further research is needed to ensure the safety of using low coarse aggregate content in SCC in highly seismic areas and assess the safety of already existing buildings cast using SCC.