000018465 001__ 18465
000018465 005__ 20170118182223.0
000018465 04107 $$aeng
000018465 046__ $$k2017-01-09
000018465 100__ $$aCesmeci, Sevki
000018465 24500 $$aFundamental Dynamics of 3-Dimensional Seismic Isolation

000018465 24630 $$n16.$$pProceedings of the 16th World Conference on Earthquake Engineering
000018465 260__ $$b
000018465 506__ $$arestricted
000018465 520__ $$2eng$$aSeismic isolation systems for buildings are generally selected to achieve higher seismic performance objectives, such as continued operation or immediate occupancy following a design earthquake event. However, recent large scale tests have suggested that these objectives may be compromised if the shaking includes large vertical acceleration components that are damaging to the nonstructural components and contents. Some research has been conducted to develop three dimensional isolation systems that can isolate the structure from both the horizontal and vertical components of ground motion. In several cases, systems have been proposed without much justification of the target design parameters. Rocking has been noted as a potential concern for structures with 3D isolation systems, and complex systems have been proposed to control the rocking. In this study, the fundamental dynamic response of structures with 3D isolation systems is explored. Target horizontal and vertical spectra for a representative strong motion site were developed based on NEHRP recommendations, and horizontal and vertical ground motions were selected that best fit the target spectra when the same amplitude scale factor was applied to all three motion components. Using a simple model of a rigid block resting on linear isolation bearings, the following aspects are evaluated for a wide range of horizontal and vertical isolation periods: response modes and severity of rocking, horizontal and vertical displacement demands in the isolation bearings, and attenuation of both horizontal and vertical accelerations in the structure relative to the ground acceleration. Preliminary results point to a number of useful observations. For example, rocking appears to be an issue only if the horizontal and vertical isolation periods are closely spaced. Helical spring isolation systems that have been applied to a few structures have this characteristic. However, if the horizontal isolation period is large relative to the vertical isolation period, troublesome rocking can be avoided. In addition, other researchers have proposed systems with vertical isolation periods on the order of 2 seconds, which require large displacement and damping capacity. However, preliminary results suggest that vertical isolation periods as low as 0.5 seconds will be effective in attenuating the vertical acceleration. Limiting the vertical isolation period will make design of a 3D isolation system more feasible with respect to vertical displacement capacity and avoiding rocking.

000018465 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000018465 653__ $$aSeismic isolation, Vertical, Structural dynamics

000018465 7112_ $$a16th World Conference on Earthquake Engineering$$cSantiago (CL)$$d2017-01-09 / 2017-01-13$$gWCEE16
000018465 720__ $$aCesmeci, Sevki$$iGordaninejad, Faramarz$$iEltahawy, Walaa$$iRyan, Keri
000018465 8560_ $$ffischerc@itam.cas.cz
000018465 8564_ $$s923002$$uhttps://invenio.itam.cas.cz/record/18465/files/1508.pdf$$yOriginal version of the author's contribution as presented on USB, paper 1508.
000018465 962__ $$r16048
000018465 980__ $$aPAPER