Dynamic Reliability Analysis of Mega-Sub Isolation System Under Random Ground Motion

The equation of motion of the mega-sub isolation system is derived in the present study. Then, the parameter optimization of the mega-sub isolation system is studied to illustrate the effects of the damping and stiffness of the isolation devices on the reliability of the system.

Moreover, based on the first passage mechanism, the calculation procedure of the dynamic reliability of the system is presented. In this procedure, the story drift of the structure is used as the evaluation.

Numerical example shows that when the damping ratio of the isolation device is given, the overall reliability of the structure increases at first then decreases with increased frequency ratio, when the frequency ratio is constant, the overall reliability of the structure increases with increased damping ratio. In addition, compared to the aseismic system, the overall reliability of the mega-sub isolation system is significantly improved.