A novel viscous-damping rubber bearing for dual control of operational vibration and seismic response of electrical equipment

Electrical equipment is vulnerable to seismic excitation and operational vibration, which compromises its safety and operational stability. This study proposes a novel viscous-damping rubber bearing (VDRB) that integrates laminated thick-rubber layers with a viscous damping component for multidimensional seismic isolation and operational vibration mitigation of electrical equipment. A novel compression correction method (CCM) is developed to predict the vertical stiffness of VDRBs with ultra-low shape factors. The vertical and horizontal mechanical properties and damping performance of the VDRBs are experimentally evaluated, while the effects of the first and second shape factors (S 1 and S 2 ) on vertical stiffness are investigated in Abaqus. A case study is conducted to assess the effectiveness of the VDRB for vibration control. Results show that the CCM predicted the measured vertical stiffness with errors within 2.2%. The VDRB exhibits nonlinear stiffening under vertical compression, whereas its equivalent shear stiffness decreases with increasing compressive pressure. Within the investigated test range, higher fluid viscosity and larger displacement amplitudes increased the equivalent horizontal stiffness of the VDRB. At a fixed fluid viscosity, displacement amplitude, and vertical preload, increasing the loading frequency from 0.05 Hz to 0.20 Hz increases both the equivalent horizontal stiffness and the energy dissipated per cycle. The reactor case study demonstrates reductions in peak horizontal acceleration of 61.6%-79.8% under the selected ground motions and a reduction in peak vertical acceleration of up to 92.2% under the investigated harmonic loads.