ABSTRACT
Seismic events and fatigue loading can both have catastrophic consequences for bridge struc- tures. While an earthquake can induce a significant force through its waves, leading to immediate collapse, fatigue loading creates a smaller force, initiating and propagating cracking in a steel element due to high stress concentration. Multiple methods have been proposed to lower the seismic amplitude applied to structures, in- cluding base isolation and energy dissipation devices. A number of strengthening methods have also been intro- duced to resolve fatigue cracks, including hole drilling, stitching, welding and cold expansion. However, these methods have disadvantages, including insufficient performance, making the steel brittle, non-economical and requiring long installation times. Furthermore, numerous case studies of failed structures have been described as being due to these two causes. Some studies have proposed using shape memory alloy (SMA), which can significantly increase damping ratios, self-center bridges, enhance the fatigue life of steel structures due to its superior properties such as its super-elasticity, and initiate recovery stress. This paper presents a state-of-the-art review of the use of SMA for the seismic strengthening and enhancement of the fatigue life of steel structures.
