Influence of freeze–thaw cycles and aging on the horizontal mechanical properties of high damping rubber bearings

Freeze–thaw cycles, aging, and freeze–thaw cycles superimposed aging test on high-damping rubber bearings (HDR) were performed to study the durability of HDR for sea-crossing bridges in northern coastal areas. The change laws of horizontal mechanical properties of HDR under different tests were revealed. After freeze–thaw cycles, the equivalent damping ratio and yield force of HDR decreased, the post-yield stiffness increased slightly, but the horizontal equivalent stiffness wasn’t change; The ultimate shear force and displacement of HDR abated. Under aging test, horizontal equivalent stiffness and post-yield stiffness increased significantly, and the change of its yield force could be ignored, while the equivalent damping ratio decreased. The horizontal equivalent stiffness and post-yield stiffness of HDR increased; however, the equivalent damping ratio and yield force decreased after the freeze–thaw cycles superimposed aging test. Besides, experimental results indicated considering freeze–thaw cycles or aging alone cannot accurately estimate the change of HDR’s performances in the actual environment. This study is likely to provide a whole life cycle design and evaluation basis for coastal seismically isolated bridges with HDR in the cold regions of northern China.