The Earthquake Engineering Online Archive

Analytical and numerical study on buckling of elastomeric bearings with various shape factors

Kelly, James M.; Takhirov, Shakhzod

UCB/EERC-2004/03, Earthquake Engineering Research Center, University of California, Berkeley, 2004, 72 pages (400/E177/2004-03)

The study presents the major findings of the theory for the buckling of elastomeric bearings based on the assumption of a linear relationship between the strain and stress in the rubber material. The theory also predicts that the vertical stiffness of the bearing is strongly dependent on the shear deformation. The theoretical results are compared with a finite element analysis conducted on numerical models with various shape factors. The rubber material in the numerical models is assumed incompressible or almost incompressible and can undergo large deformations when the stress-strain relationship becomes significantly nonlinear. The buckling theory of elastomeric bearings predicts that buckling can occur in compression and in tension as well. The numerical part of the study not only confirms this theoretical result but also shows adequate correlation between the theoretical and numerical buckling loads. The theoretical modes of the tension and compression buckling have an excellent correlation with the results of the numerical study. The theoretical vertical stiffness significantly decreases as the shear deformation of the bearing increases. This theoretical finding is also confirmed by the numerical analysis conducted on the finite element models of bearings with various shape factors.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-04-03.pdf (1 MB)