Reliability of base isolation for the protection of critical equipment from earthquake hazards

Alhan, Cenk; Gavin, Henri P.

doi:10.1016/j.engstruct.2005.04.007

Cited by 93 publications

(50 citation statements)

References 23 publications

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“…They found that the isolation systems can reduce the high-frequency micro vibrations of protected structures; however, some studies have revealed that friction-type isolators can generate high-frequency acceleration responses during earthquakes [3,4]. Alhan and Gavin [5,6] performed a parametric study on isolation systems, further verifying the isolation system's reliability in protecting equipment. They found that the reliability is higher for far-field earthquake motion than it is for the near-fault kind because the pulse-like seismic motions of the near-fault region could impede the performance of the isolation system at the desired level.…”

Section: Introductionmentioning

confidence: 97%

Performance of a guideway seismic isolator with magnetic springs for precision machinery

Yao

Huang

2008

Earthq Engng Struct Dyn

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SUMMARYThis paper proposes the use of the nonlinear restoring force in an isolation system to improve the performance of a seismic isolator. Nonlinear magnetic springs applied to guideway sliding isolators (GSI) that protect precision machinery against seismic motion were studied. The magnetic springs use a noncontact magnetic repulsion force to achieve a nonlinear property. A numerical simulation model of the GSI system using step-by-step integration in the time domain was developed. A full-scale shaking table test was performed to verify the accuracy of the numerical model. Simulation and experimental results show that the GSI system with magnetic springs has good performance when subjected to floor vibrations during earthquakes. A parametric analysis of the magnetic springs in the GSI system under seismic motion was theoretically investigated. It was found that sufficient magnetic forces can diminish the system relative displacements.

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Section: Introductionmentioning

confidence: 97%

Performance of a guideway seismic isolator with magnetic springs for precision machinery

Yao

Huang

2008

Earthq Engng Struct Dyn

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“…the facility floor acceleration A f 2. the relative story displacement X r 3. the isolation (or first-floor) displacement X I Accelerations of magnitude 100 − 300 × 10 −3 g are specified by computer manufacturers [37] as the limit range at which these sensitive computers fail. [13] Here, A f is taken to be 100 × 10 −3 g. For the relative-story displacement, commonly used building codes take the allowable drift ratio to be 0.004. This value guarantees the elastic behavior of the superstructure.…”

Section: Superstructurementioning

confidence: 99%

“…Simulation-based methods for reliability analysis are effective tools for calculating the probability of failure (P f ) or reliability index (β) of an isolated structure subjected to random earthquake excitations. [13] An important issue in such methods is the computation cost. For complex systems where the derivation of joint probability-distribution functions is difficult, the probability of failure is evaluated by MCSs.…”

Section: Introductionmentioning

confidence: 99%

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Novel procedure for reliability-based cost optimization of seismically isolated structures for the protection of critical equipment: A case study using single curved surface sliders

Moeindarbari

Taghikhany

2017

Struct Control Health Monit

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SummaryThe optimized reliability-based design of seismic isolated structures requires a consideration of the failure probability of the system, in addition to the optimization objectives. The stochastic nature of a given system (e.g., the probable input ground motion) must therefore be properly included in the analysis model. To address this challenge, a novel procedure is developed and examined on a 3-story isolated concrete building model, to minimize the total construction cost of the system with regards to protecting sensitive equipment located within the structure.In this procedure, the structure performance and reliability were first evaluated using time-consuming Monte Carlo simulations. We then employed artificial neural networks as a response surface to facilitate the prediction of the failure probability for the supposed structure. To simulate seismic excitations, we generated artificial ground motion combining random high-frequency and long-period components.Also, a newly developed sensitivity analysis method was used to identify the critical uncertain parameters of the system. Finally, by using a simulated annealing algorithm, we determined the optimal design variables of the structure and isolation system for a range of desired probabilities of failure.The optimal results indicate that, for different target failure probability ranges, some design variables are more significant than others. KEYWORDS base isolation, critical equipment protection, neural network, reliability based cost optimization, sensitivity analysis, spectral non-stationarity

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“…The base isolation technology, [3], is in construction one of the most advanced protections against earthquakes that contain critical devices such as computer servers [4], electronic equipments [5,6], precision machinery [7], etc. According to [8], the two main challenges in the design of structures with seismic isolation are the consideration of the variability of ground motions, see [9], and the non-linear response of the isolators.…”

Section: Introductionmentioning

confidence: 99%

Reliability-based dynamical design of a singular structure for high energy physics experiments

Palma

Torrent

Pérez-Aparicio

et al. 2018

Archives of Civil and Mechanical Engineering

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The present work presents a comprehensive design and dynamic calculation of singular metallic structures, part of the Neutrino Experiment NEXT. The experiment uses an electroluminescent TPC chamber, a high-pressure 136Xe gas vessel enclosing the detector. A lead-block "castle" or containing box shields this vessel against external γ-rays from all directions; in spite of its heavy weight, the castle must be regularly open for the detector maintenance. Since the structures will be constructed at a middle-level seismic localization (Laboratorio Subterráneo Canfranc, Spain), the earthquake hazard must be taken into account. Vessel and castle are supported by a rigid frame, which must satisfy two requirements: i) the Spanish seismic standard, ii) for equipment protection, the detector maximum horizontal acceleration must be < 1 [m/s 2 ]. This frame rests on special base isolators to decrease horizontal accelerations in case of an earthquake. Three dynamical calculations are conducted: i) a response spectrum analysis to comply with the standard, ii) five time-history analyses to calculate tolerances and, iii) a reliability-based approach using 1,000 timehistory responses to ensure satisfaction of the operating requirements. The final outcome is the design of a singular structure optimized for the NEXT experiment with a probability of failure against any standard earthquake of only 0.125%.

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Reliability of base isolation for the protection of critical equipment from earthquake hazards

Cited by 93 publications

References 23 publications

Performance of a guideway seismic isolator with magnetic springs for precision machinery

Performance of a guideway seismic isolator with magnetic springs for precision machinery

Novel procedure for reliability-based cost optimization of seismically isolated structures for the protection of critical equipment: A case study using single curved surface sliders

Reliability-based dynamical design of a singular structure for high energy physics experiments

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