A NEW ANALYTICAL MODEL FOR SEISMIC ISOLATION BEARINGS SUBJECT TO ECCENTRIC BENDING MOMENTS AND SHEAR DEFORMATION

This paper presents a new analytical model for predicting the behavior of elastomeric seismic isolation bearings subject to combined eccentric bending moments and shear deformation. The mechanical model consists of a series of axial springs at the top, mid-height and bottom of the isolator. The model can account for end rotations of the isolator, and the overall isolator rotational stiffness can include the influence of the variation of vertical load on the isolator and the imposed shear deformation. To identify the mechanical characteristics of isolators, static bending tests under various combinations of vertical load and shear deformation were performed. The results of analyses using the new model show very good agreement with experimental observations.