000018678 001__ 18678
000018678 005__ 20170118182236.0
000018678 04107 $$aeng
000018678 046__ $$k2017-01-09
000018678 100__ $$aQuaglini, Virginio
000018678 24500 $$aEffects of Permanent Offset on the Response of the Curved Surface Sliders

000018678 24630 $$n16.$$pProceedings of the 16th World Conference on Earthquake Engineering
000018678 260__ $$b
000018678 506__ $$arestricted
000018678 520__ $$2eng$$aThe large worldwide diffusion of isolation systems with Curved Surface Sliders (CSS), also known as the Friction Pendulum System®, requires detailed knowledge of their behavior and improved modelling capability under seismic conditions. Restoring capability after the earthquake is one of the fundamental functions required to seismic isolation systems. It is noted the dependency of residual displacements on ground motions characteristics and isolator mechanical properties, namely the radius of curvature and the coefficient of friction. Current standards on antiseismic devices (EN15129, AASHTO) and design codes (Eurocode 8) provide criteria to ensure good restoring capability. An analytical model has also been formulated based on numerical analysis to predict the residual displacement of the isolation system. In mainshock-aftershock sequences it is possible that at the occurrence of the aftershock the isolation system present an offset from its original configuration as a result of the main shock. The main concern is whether or not an increase in the maximum or residual displacement consequent to the displacement accrual starting from the offset position may lead, under certain conditions, to exceed the displacement capacity of CSS device and the structural integrity or compromise the serviceability of the structure. In this study, some hundreds of nonlinear time-history analyses of SDOF systems were conducted within an extensive parametric study aimed to investigate the effects of a non-centered initial position on the CSS response, in terms of maximum and residual displacements. Five different initial offsets were considered coupled with a wide range of devices and earthquakes, characterized by different values of the isolator design parameters and characteristics of the ground motion. Twenty different CCS isolators were considered varying five radii of curvature (from 2 200 mm to 5 000 mm) and four friction laws, covering the current design practice. Twenty-four natural ground motion time histories were selected from a database and classified in terms of the predominant period of the quake and the level of impulsivity (to this scope, a “Pulse Index” was formulated based on the rate of transmission of the kinetic energy). The effects of an initial offset are discussed herein in terms of maximum and residual displacements of the isolators. The displacement responses obtained in presence of the offset are eventually compared with the relevant response provided by the isolation system that moves from its centred configuration.

000018678 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000018678 653__ $$aCurved Surface Slider, re-centering, parametric study

000018678 7112_ $$a16th World Conference on Earthquake Engineering$$cSantiago (CL)$$d2017-01-09 / 2017-01-13$$gWCEE16
000018678 720__ $$aQuaglini, Virginio$$iGandelli, Emanuele$$iDubini, Paolo
000018678 8560_ $$ffischerc@itam.cas.cz
000018678 8564_ $$s524794$$uhttps://invenio.itam.cas.cz/record/18678/files/198.pdf$$yOriginal version of the author's contribution as presented on USB, paper 198.
000018678 962__ $$r16048
000018678 980__ $$aPAPER