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Optimal design of friction pendulum system properties for isolated structures considering different soil conditions
No full textThis studyaimsatevaluatingtheoptimalpropertiesoffrictionpendulumbearingstobeemployedfor
the seismicprotectionofelasticisolatedstructuralsystemsunderearthquakeexcitationswithdifferent
characteristicsintermsoffrequencycontent.Atwo-degree-of-freedommodelisconsideredtodescribe
the isolatedsystembehaviorwhileaccountingforthesuperstructure flexibilityandanon-dimensional
formulation ofthegoverningequationsofmotionisemployedtorelatethecharacteristicparameters
describing theisolatorandstructurepropertiestotheresponseparametersofinterestfortheperfor-
mance assessment.Seismicexcitationsaremodeledastime-modulated filteredGaussianwhitenoise
random processesofdifferentintensitywithinthepowerspectraldensitymethod.The filter parameters
control thefrequencycontentoftherandomexcitationsandarecalibratedtodescribestiff,mediumand
soft soilconditions,respectively.Finally,multi-variateregressionexpressionsareobtainedfortheopti-
mum valuesofthefrictioncoefficient thatminimizethesuperstructuredisplacementsrelativetothe
base massasafunctionofthestructuralsystemproperties,oftheseismicinputintensityandofthesoil
condition.This study aims at evaluating the optimal properties of friction pendulum bearings to be employed for the seismic protection of elastic isolated structural systems under earthquake excitations with different characteristics in terms of frequency content. A two-degree-of-freedom model is considered to describe the isolated system behavior while accounting for the superstructure flexibility and a non-dimensional formulation of the governing equations of motion is employed to relate the characteristic parameters describing the isolator and structure properties to the response parameters of interest for the performance assessment. Seismic excitations are modeled as time-modulated filtered Gaussian white noise random processes of different intensity within the power spectral density method. The filter parameters control the frequency content of the random excitations and are calibrated to describe stiff, medium and soft soil conditions, respectively. Finally, multi-variate regression expressions are obtained for the optimum values of the friction coefficient that minimize the superstructure displacements relative to the base mass as a function of the structural system properties, of the seismic input intensity and of the soil condition
Edizione Italiana riveduta ed ampliata del volume: Thibodeau/Anthony, Structure and Function of the Human Body IX Edition, Mosby - Year Book Inc.
No full textOptimal design of friction pendulum system properties for isolated structures considering different soil conditions
No full textThis study aims at evaluating the optimal properties of friction pendulum bearings to be employed for the seismic protection of elastic isolated structural systems under earthquake excitations with different characteristics in terms of frequency content. A two-degree-of-freedom model is considered to describe the isolated system behavior while accounting for the superstructure flexibility and a non-dimensional formulation of the governing equations of motion is employed to relate the characteristic parameters describing the isolator and structure properties to the response parameters of interest for the performance assessment. Seismic excitations are modeled as time-modulated filtered Gaussian white noise random processes of different intensity within the power spectral density method. The filter parameters control the frequency content of the random excitations and are calibrated to describe stiff, medium and soft soil conditions, respectively. Finally, multi-variate regression expressions are obtained for the optimum values of the friction coefficient that minimize the superstructure displacements relative to the base mass as a function of the structural system properties, of the seismic input intensity and of the soil condition
Seismic fragility of structures isolated by single concave sliding devices for different soil conditions
No full textThis study deals with the seismic fragility of elastic structural systems equipped with single concave sliding (friction pendulum system (FPS)) isolators considering different soil conditions. The behavior of these systems is analyzed by employing a two-degree-of-freedom model, whereas the FPS response is described by means of a velocity-dependent model. The uncertainty in the seismic inputs is taken into account by considering artificial seismic excitations modelled as timemodulated filtered Gaussian white noise random processes of different intensity within the power spectral density method. In particular, the filter parameters, which control the frequency content of the random excitations, are calibrated to describe stiff, medium and soft soil conditions. The sliding friction coefficient at large velocity is also considered as a random variable modelled through a uniform probability density function. Incremental dynamic analyses are developed in order to evaluate the probabilities of exceeding different limit states related to both the reinforced concrete (RC) superstructure and isolation level, defining the seismic fragility curves within an extensive parametric study carried out for different structural system properties and soil conditions. The abovementioned seismic fragility curves are useful to evaluate the seismic reliability of base-isolated elastic systems equipped with FPS and located in any site for any soil condition
Arterial microvasculature and blood flow regulation in rat retina. A comparative analysis of corrosion casts and digested tissue specimens by S.E.M.
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Constitutive modeling for failure properties analysis of concrete with recycled aggregates
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