Elastomeric bearings designed for aseismic base isolation typically have a low shear rigidity in order to achieve a low isolation frequency and are thus modeled by a flexural-shear column on the basis of Haringx’s theory. The buckling load of a flexural-shear column is considerably reduced by the shear effect. It is therefore essential to account for the stability effect due to a compressive load on the dynamic performance of these bearings. In this paper, an exact viscoelastic model consistent with Haringx’s theory is first reviewed. A simplified symmetric model consisting of springs and rigid plates is then discussed. Experimental results for four different sets of natural rubber bearings are presented. It is shown that both models can describe with good accuracy the stability effects on the dynamic stiffness, damping factor and height reduction of bearings. In spite of its simplicity, the simplified model is found to agree very well with the exact model. Lastly, using the simplified model, the applicability of the Southwell plot to predict the buckling load of elastomeric isolation bearings is examined.

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