The Effect of Temperature on Seismic Response of Cu–Al–Mn SMA Braced Frame

Abstract

Cu–Al–Mn is a type of shape memory alloy that has been evaluated for seismic applications in recent years. However, the rate-independent behavior of this new material has been proved in seismic applications in previous studies, but dependency on the temperature has been rarely studied. In this paper, seismic response dependency in a steel braced frame was evaluated under five different temperatures: − 40, − 25, 0, 25 and 50 °C. For this purpose, a one-bay one-story Cu–Al–Mn X braced frame was selected. At first, the response of frame was provided under a record scaled with various PGA and then five scaled records were selected for more evaluation. From the results, the axial force and top acceleration of frame increased with enhancing temperature. The difference of top acceleration in the lowest and highest temperature was 30%. In contrast, there was a drop in the maximum drift and maximum strain of brace with increasing temperature. The percentage changes of maximum drift and maximum strain were in the average values of 44 and 47%, respectively. Changes in all cases were almost linear. Results of the frame under seven different scaled records almost showed similar tendency. However, change in environmental temperature affected time history drift angle, especially at a temperature less than 0 °C, but in most earthquakes, maximum drift angle and strain increased with decreasing temperature and there was decline in top acceleration. The percentage of changes varied from 32 to 72% for drift angle and 20–42% for top acceleration.