Taking into account the earthquake-resistant design standards in effect when the building was designed, new earthquake-resistant design criteria were established for the retrofit, to check the earthquake-resistant safety of the retrofit design. Structural and functional considerations led to a choice of laminated rubber for the isolator material. The results of vibration analysis using a mass system model demonstrated that the earthquake motion input into the building would be reduced substantially by the retrofitwork. It was also shown that the work would substantially meet the earthquake-resistant design criteria. Three-dimensional vibration analysis was also carried out using a solid frame model to calculate the margin of safety of each structural member would be earthquake-resistant.
