Probabilistic analysis of seismic mitigation of base‐isolated structure with sliding hydromagnetic bearings based on finite element simulations

Abstract

Base isolation is one of the most efficient methods for seismic mitigation of building and bridge structures in high‐intensity areas. However, the base‐isolated structure designed according to current codes based on the local seismic hazard and a few station records might not guarantee the performance of the base isolation system and ensure the safety of the structure. Carrying out a probabilistic analysis of seismic mitigation of base‐isolated structures, considering the randomness associated with earthquake ground motions, is thus necessary. To this end, the stochastic seismic response and reliability analysis of base‐isolated structures subjected to stochastic ground motions are conducted in this study, in conjunction with the probability density evolution method and the principle of equivalent extreme value event. The recently developed sliding hydromagnetic bearing is employed to constitute the base isolation layer of the base‐isolated structure. A refined finite element analysis is carried out to accurately reveal the dynamic characteristics of the base‐isolated structure. It is shown that the base‐isolated structure can be well simulated by the finite element model, which is verified through a comparative study with the results of shaking‐table tests. The base‐isolated structure gains a sound seismic mitigation compared to the base‐fixed structure in a probabilistic sense, and can ensure the safety of the structure by deploying a moderately designed base isolation system.

Reliability-based design optimization for seismic structures considering randomness associated with ground motions

“…The above definition of reliability holds when there is involvement of a single limit state function only, i.e., when a single mode of failure is considered or when only one member or element of the structure fails. However, when assessing the reliability of a structure, we typically need to consider multiple modes of failure or multiple failures of elements, as represented by the following equation [7,10,37] :…”

“…The foundational model of the physically motivated stochastic ground motion was initially introduced by Professors Wang and Li in their work [26] . Building upon this model, Peng et al [8,37] have applied it in various studies, employing it for generating stochastic ground motions and conducting RBDO and probabilistic analyses for adaptive sliding base isolation systems and base-isolated structures with sliding hydro-magnetic bearings. Additionally, this ground motion model has been used alongside the absorbing boundary condition of PDEM to facilitate the probabilistic optimization of TMDI (Tuned Mass Damper-Inerter) systems, as demonstrated by Sun et al [38] .…”