Behaviour of concrete beams reinforced with SMA and steel bars under cyclic and monotonic load

Abstract

This paper presents cyclic and monotonic load test results of concrete flexural members reinforced with shape memory alloy (SMA) and conventional steel bars. The ability of the SMA bars to recover and reduce permanent deformations of concrete flexural members subjected to cyclic load was investigated using reinforced concrete (RC) beam models. Half were control beams, reinforced with conventional steel bars, and the remainder were treated beams, reinforced with both conventional steel and SMA bars. The cyclic load test results showed that there were negligible increments in deflection and the ratio of residual deflection to maximum deflection was almost zero in beams with SMA bars over the whole span. Initially, under lower values of load, the stiffness of the treated beams was slightly higher than that of the control beams, but reduced with an increase in imposed load. The load–deflection behaviours of the treated and control beams were verified using published codes and standards. The results indicate that RC flexural members with SMA and steel provide a better choice for structures subjected to cyclic loads and/or earthquakes.