Response of a seismically isolated structure exposed to various low temperatures and exposure times

The aim of this study is to examine the behavior of seismically isolated structure with lead rubber bearings (LRB) exposed to different low ambient temperatures and different exposure times. For this purpose, the results of dynamically tested large-size LRB, performed within the scope of another study, were used. The tests were performed at 0ºC, -10ºC and -20ºC temperatures at 3, 6, 24 hours exposure times. The amplitude of the motion during the tests were 50%, 100% and 134% shear strains and subjected with a frequency of 0.5 Hz. Within the scope of this study, the mechanical properties of the LRB obtained from these tests carried out for different situations were transferred to analytical models, and nonlinear time history analyzes were carried out with a typical bridge model, and maximum isolator displacement, maximum isolator force and maximum accelerations were calculated. It has been observed that the changes in the isolator mechanical properties also lead to significant changes in these structural responses. The results obtained were compared with the results of bounding analyses using the property modification factors stipulated by various codes, and the success of the bounding analyses to determine the isolator responses was examined.