Mechanical properties of superelastic Cu-Al-Be wires at cold temperatures for the seismic protection of bridges

This paper examines the suitability of superelastic copper-aluminum- beryllium (Cu-Al-Be) alloy wires for the seismic protection of bridges in cold regions. Experimental results for the mechanical properties of superelastic Cu-Al-Be alloy wires at a variety of temperatures and loading rates are presented. This research is motivated by the recent use of shape memory alloys for bridge restrainers subject to harsh winter conditions, especially in cold regions. Bridge restrainers made of superelastic Cu-Al-Be wire strands are expected to be used for protecting bridge decks from excessive displacement when subjected to strong earthquakes. Using a temperature chamber, superelastic Cu-Al-Be wires with a diameter of 1.4 mm were tested under uniaxial cyclic loading at various loading rates and cold temperatures. The test results from 23 to -50°C demonstrate that Cu-Al-Be exhibits superelastic behavior at cold temperatures down to -85°C. It is also found that with decreasing temperature the transformation plateau stress is reduced while its fatigue life increases under cyclic testing.