Fatigue behavior of RC beams strengthened with iron-based shape memory alloy rebars

This paper presents the experimental research results on the fatigue behavior of reinforced concrete (RC) beams integrated with prestress using iron-based shape memory alloys (Fe-SMAs). Four RC beams reinforced with Fe-SMA rebars as tensile members were fabricated for the fatigue experiments. The experimental variables included the type of load (static and fatigue) and the size of the fatigue load (40 %, 50 %, and 60 % of the maximum load). Before the experiments, prestress was introduced into the Fe-SMA rebars through electric resistance heating. The minimum load for the fatigue test was set at 20 % of the maximum load of the control beam, and the tests were conducted at a frequency of 2 Hz. As the number of fatigue load cycles increased, all specimens exhibited an increasing trend in deflection and strain. The specimens subjected to fatigue loads of 50 % and 60 % of the maximum load failed due to the crushing of the compression concrete and the fracture of the Fe-SMA rebars, respectively. In contrast, the specimen subjected to 40 % of the maximum load showed a similar load resistance capacity to the control beam even after enduring 2 million cycles of fatigue load. •The fatigue behavior of RC beams with self-prestress using Fe-SMA rebars was investigated experimentally.•The fatigue performance of Fe-SMA rebar under various loading conditions was investigated.•Fe-SMA exhibited a high-cycle fatigue response at stress levels exceeding its yield strength.•RC beams reinforced with Fe-SMA showed great fatigue performance under load conditions below the crack load.