Variable Stiffness Protection Device of Rubber Bearings in Seismic Isolated System

This article deduced the equation of motion for non-affixation of spring, right affixation of spring and left affixation of spring on the basis of the multi-particle structural analytic model, and developed the computer program to prevent the failure of rubber bearing under low-frequency excitation. A shaking table test of a five-floor steel-frame model was completed successfully in Beijing University of Technology. The results showed that the variable stiffness isolated protection device can effectively reduce the horizontal deformation to prescribed limits, and can prevent the rubber bearings from failure because the dynamic character of the structure has been changed, and can make the interlayer shear forces in the super-structure increase slightly.