PASSIVE VARIABLE ORIFICE DAMPER TO CONTROL EXCESSIVE DISPLACEMENT OF SEISMICALLY ISOLATED BUILDING

The developed oil damper changes the damping force passively and steplessly depended on damper displacement at low speeds of approximately 30 cm/s or less. A prototype damper with a maximum force of about 500 kN was tested and it was confirmed that the damping force changed as expected. Numerical analysis using the damper with the characteristics of the experimental results confirmed that the maximum displacement of the isolation layer was reduced by about 15% during long-period earthquakes, and that the acceleration response during moderate earthquakes was equivalent to that of a conventional seismically isolated building.