Vertical and Three-Dimensional Seismic Isolation Tables with Bilinear Spring Force Characteristics (For Which a .LAMBDA.-Shaped Link Mechanism Is Used)

Ueda, Mari; Ohmata, Kenichiro; Yamagishi, Ryohei; Yokoo, Jyunichi

doi:10.1299/kikaic.73.2932

Cited by 7 publications

(2 citation statements)

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“…In this figure, d is total displacement (summation of static and dynamic displacement). Ueda et al (2007) proposed a vertical isolation system consisting of Λ-shaped link with softening behavior in compression. In contrast to Vshaped link springs, conical springs show hardening behavior in compression (Rodriguez et al, 2006, Wu andHsu, 1998).…”

Section: Nonlinear Spring and Linear Dampermentioning

confidence: 99%

“…Cimellaro et al (2019), Meng et al (2015) and Zhou et al (2019) studied the application of negative or quasi-zero stiffness devices proposed for vertical vibration mitigation for light, sensitive equipment. In an opposite approach, Ueda et al (2007) and Wakabayashi et al (2009) proposed vertical softening isolation systems through the use of Λ and V-shaped links, respectively, in an effort to reduce static displacement while maintaining flexibility under larger earthquakes. Asai et al (2008) used constant load springs under the equipment which also results in a softening system where the transmitted load and therefore the equipment acceleration is limited through the spring load design.…”

Section: Introductionmentioning

confidence: 99%

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Evaluating adaptive vertical seismic isolation for equipment in nuclear power plants

Najafijozani

Becker

Konstantinidis

2020

Nuclear Engineering and Design

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Seismic isolation systems are widely recognized as beneficial for protecting both acceleration-and displacement-sensitive nonstructural systems and components. So-called adaptive isolation systems exhibit nonlinear characteristics that enable engineers to achieve various performance goals at different hazard levels. These systems have been implemented to control the horizontal response, but there has been limited research on seismic isolation for controlling the vertical response. Thus, this paper seeks to evaluate the benefit of adaptive vertical isolation systems for components, specifically in nuclear power plants (NPP). To do this, three vertical isolation systems are designed to achieve multiple goals: a linear spring and a linear damper (LSLD), a linear spring and a nonlinear damper (LSND) and a nonlinear spring and a linear damper (NSLD). To investigate the effectiveness of the systems, a stiff piece of equipment is considered at an elevated floor within a NPP. A set of 30 triaxial ground motions is used to investigate the seismic performance of the equipment. The maximum isolation displacement and equipment acceleration are used to assess the effectiveness of the three isolation systems. While all systems significantly reduce the seismic accelerations on the equipment, the relatively simple LSLD and LSND systems exhibit superior performance over multiple hazard levels.

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Section: Nonlinear Spring and Linear Dampermentioning

confidence: 99%