scholarly journals Design Method of Vertical Component Isolation System

2002 ◽  
Author(s):  
S. Kitamura ◽  
M. Morishita
Keyword(s):  
Base Isolation ◽  
Design Method ◽  
Vertical Component ◽  
Reactor Vessel ◽  
Isolation System ◽  
Structural Concept ◽  
Base Isolation System ◽  
Series Of Experiments ◽  
Isolation Device

A structural concept of a vertical component isolation system for fast reactors, assuming a building adopting a horizontal base isolation system, has been studied. In this concept, a reactor vessel and major primary components are suspended from a large common deck supported by isolation devices consisting of large coned disk springs. A series of experiments using a simple model for the confirmation of the isolation effect, and a case study of vertical isolation device and plant layout are shown in this paper.

Study on Vertical Component Seismic Isolation System With Coned Disk Spring

2004 ◽  
Author(s):  
S. Kitamura ◽  
M. Morishita ◽  
S. Moro
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Vertical Component ◽  
Reactor Vessel ◽  
Full Scale ◽  
Fast Reactors ◽  
Isolation System ◽  
Disk Spring ◽  
Structural Concept ◽  
Base Isolation System

A structural concept of a vertical component isolation system for fast reactors, assuming a building adopting a horizontal base isolation system, has been studied. In this concept, a reactor vessel and major primary components are suspended from a large common deck supported by isolation devices consisting of large coned disk springs. The outline of the vertical component seismic isolation system and a series of model tests with full scale coned disk spring and damper are shown in this paper.

scholarly journals Influence of Elastomeric Bearings in Tension on the Seismic Performance of Base-Isolated r.c. Buildings

2020 ◽  
Vol 11 (1) ◽  
pp. 82
Author(s):  
Fabio Mazza ◽  
Mirko Mazza
Keyword(s):  
Base Isolation ◽  
Nonlinear Models ◽  
Vertical Component ◽  
Computer Code ◽  
Nonlinear Phenomena ◽  
Isolation System ◽  
Elastomeric Bearings ◽  
Near Fault ◽  
Base Isolation System ◽  
Near Fault Earthquakes

Elastomeric bearings are commonly used in base-isolation systems to protect the structures from earthquake damages. Their design is usually developed by using nonlinear models where only the effects of shear and compressive loads are considered, but uncertainties still remain about consequences of the tensile loads produced by severe earthquakes like the near-fault ones. The present work aims to highlight the relapses of tension on the response of bearings and superstructure. To this end, three-, seven- and ten-storey r.c. framed buildings are designed in line with the current Italian seismic code, with a base-isolation system constituted of High-Damping-Rubber Bearings (HDRBs) designed for three values of the ratio between the vertical and horizontal stiffnesses. Experimental and analytical results available in literature are used to propose a unified nonlinear model of the HDRBs, including cavitation and post-cavitation of the elastomer. Nonlinear incremental dynamic analyses of the test structures are carried out using a homemade computer code, where other models of HDRBs considering only some nonlinear phenomena are implemented. Near-fault earthquakes with comparable horizontal and vertical components, prevailing horizontal component and prevailing vertical component are considered as seismic input. Numerical results highlight that a precautionary estimation of response parameters of the HDRBs is attained referring to the proposed model, while its effects on the nonlinear response of the superstructure are less conservative.

Laminated Type Isolation Device for Light Weight Structure Using Urethane Elastomer

2017 ◽  
Author(s):  
Kengo Goda ◽  
Osamu Furuya ◽  
Kohei Imamura ◽  
Kenta Ishihana
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Light Weight ◽  
Loading Test ◽  
Isolation System ◽  
Seismic Safety ◽  
Base Isolation System ◽  
Weight Structure ◽  
Isolation Device ◽  
Urethane Elastomer

At the present, base isolation system has been recognized by general earthquake resistant technique since the Great Hanshin Earthquake 1995. The seismic isolation will be aggressively applied to not only architectural and civil structures but also various structures, because the effectiveness on seismic safety had been demonstrated again in the Great East Japan Earthquake. In generally, although the base isolation system is divided into laminated rubber bearing type and friction sliding bearing type. In the case of former type, shape factor, maximum or minimum outer shapes and so on are restricted by the material characteristics in visco-elastic material. In general, the isolation structure is used in high damping rubber. However, we pay attention to base isolation using urethane elastomer. Urethane elastomer has excellent elasticity, mechanical strength, abrasion resistance, weather resistance, oil resistance, impact resistance the absorbent, anti-vibration and excellent low-temperature properties. Furthermore, it is possible to impart various characteristics by a combination of isocyanate and polyol and chain extender, requires no large-scale apparatus, it has the advantage molecular design is easy. In previous study, the research and development of laminated type base isolation device using urethane elastomer was carried out to upgrade a seismic safety for various structures. The fundamental characteristics was investigated from several loading test by using various experimental devices, and the design formula for the stiffness and equivalent damping coefficient is formulated as an approximate expression of mechanical characteristics until now. It was confirmed that urethane elastomer is not hardening up to 500% shear strain. Moreover, the experimental examination for aged deterioration in the urethane material has been continuously carried out. As the results, it was confirmed that the laminated type seismic isolation device using urethane elastomer is possible to develop as a practicable device from the stable mechanical properties as considering in design step. In this study, the small-scale laminated type base isolation device using urethane elastomer is advanced to the direction of further technical upgrading and of scale down for light-weight structure as a sever rack. The first stage, basic properties of the urethane elastomer has been investigated by loading test. Furthermore, the design equation is created by loading test using urethane elastomer. The validity of the design equation has been confirmed. The second stage, the compression creep test with laminated type base isolation device has been investigated to confirm an effect on light-weight mechanical devices.

Improvement of the polyurethane spring isolation device for HV post insulators and its evaluation by fragility curves

2021 ◽  
pp. 875529302098196
Author(s):  
Tansu Gökçe ◽  
Engin Orakdöğen ◽  
Ercan Yüksel
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Numerical Models ◽  
Fragility Curves ◽  
Low Cost ◽  
Steel Plates ◽  
Isolation System ◽  
Base Isolation System ◽  
Isolation Device ◽  
Seismic Base Isolation

A novel seismic base isolation system has been developed for high-voltage (HV) porcelain post insulators. The seismic isolation device consists of two steel plates, four polyurethane springs, and a steel rod, which are low-cost components compared to the post insulators. Two alternative designs of the device are experimentally and numerically assessed in this article. A simple and robust numerical model consisting of linear line elements and nonlinear springs was generated, and subsequently validated using the experimental results. Incremental dynamic analyses (IDAs) were then performed to obtain fragility curves. Ten historical earthquake profiles, scaled to intensities between 0.1 and 2.0 g, were then applied to the numerical models. The fragility curves, generated according to the latest version of IEEE-693, demonstrate that the seismic isolation devices are highly effective in diminishing the base moment of the porcelain insulator. It should be noted that relatively large displacements at the top of the pole must be accounted for by ensuring adequate slackness in the flexible conductors.

The Isolation Effect Analysis of Base and Story Isolation System in Vertical Seismic Action

2010 ◽  
Vol 163-167 ◽  
pp. 3893-3898
Author(s):  
Shao Wei Duan ◽  
Xiao Wei Tao ◽  
Hai Kuan Liu
Keyword(s):  
Base Isolation ◽  
Material Point ◽  
Isolation Effect ◽  
Seismic Action ◽  
Isolation System ◽  
Effect Analysis ◽  
Base Isolation System ◽  
Isolation Systems ◽  
Material Points ◽  
Isolation Device

Through establishing single material point model of base isolation system and two material points model of story isolation system in vertical earthquake, the isolation effect of base and story isolation system in vertical earthquake are studied. Results show that two kinds of isolation systems cannot effectively keep apart the vertical seismic action, and the effect is amplified on the contrary, especially the position of isolation layers in story structures affect the amplification effect. Compared with the base and story isolation structures, while using the same isolation device, the former is better than the latter in isolating vertical seismic action.

scholarly journals Effective Semiactive Base Isolation System under Multiple Earthquakes

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Mohtasham Mohebbi ◽  
Hamed Dadkhah
Keyword(s):  
Control System ◽  
Numerical Simulations ◽  
Base Isolation ◽  
Design Method ◽  
Mr Damper ◽  
Semiactive Control ◽  
Maximum Acceleration ◽  
Isolation System ◽  
Base Isolation System ◽  
Multiple Earthquakes

A method is proposed to design an effective semiactive control system composed of a linear low damping base isolation and a supplemental magnetorheological (MR) damper when the structure subjected to multiple earthquakes. In the proposed design method, the parameters of semiactive control system have been determined based on minimizing the average of maximum response of isolated structure under multiple design ground motions. To select appropriate value for force related weighting parameter, defined in performance index, a range has been suggested for each design objective. For numerical simulations, a scaled three-story base-isolated frame subjected to different scaled real earthquakes as well as filtered white noise excitations and the proposed method has been applied to design semiactive base isolation system under multiple earthquakes. The results of numerical simulations have shown the capability of the proposed method in designing an effective semiactive base isolation system, the performance of which under multiple earthquakes has been almost close to the case that it is designed optimally for each earthquake separately. Also, under multiple earthquakes, using the passive-off and passive-on forms of MR damper can be recommended, respectively, regarding to the objectives of minimizing the maximum acceleration and base drift.

scholarly journals A tenacious base isolation system using round steel bars

1978 ◽  
Vol 11 (4) ◽  
pp. 273-281
Author(s):  
R. G. Tyler
Keyword(s):  
Base Isolation ◽  
Design Method ◽  
Engineering Practice ◽  
Earthquake Loading ◽  
Reinforcing Bars ◽  
Dynamic Tests ◽  
Isolation System ◽  
Earthquake Energy ◽  
Steel Bars ◽  
Base Isolation System

The tenacity of reinforcing bars in resisting earthquake loading, after concrete had spalled away around them, suggests that round bars can be used to dissipate earthquake energy in base isolated buildings, provided a bow is introduced in the bars to allow them to extend as the building deflects on its bearings. Dynamic tests are described which enable a design method for such a system to be evolved. The method has the advantage of simplicity in that round bars available in normal engineering practice can be utilised, while a tensile capacity is introduced between the structure and the foundation which enables the system to progressively lock up under disaster conditions.

Effect of Vertical Component of Earthquake on the Response of Pure-Friction Base-Isolated Structures

2013 ◽  
Vol 743 ◽  
pp. 105-109
Author(s):  
Wei Gu ◽  
Xiao Dong Wen ◽  
Wei Cai ◽  
Bin Liu
Keyword(s):  
Base Isolation ◽  
Vertical Component ◽  
Frictional Coefficient ◽  
Equation Of Motion ◽  
Masonry Structure ◽  
Dynamic Responses ◽  
Earthquake Intensity ◽  
Maximum Displacement ◽  
Isolation System ◽  
Base Isolation System

The objective of this research is to investigate the dynamic responses of the masonry structure with base-isolation system under the vertical earthquake. Through inter-story shear model with the multi-degree of freedom, the equation of motion and the distinguishing rule between slide and joggle were established. The effects of vertical component of earthquake on the response of pure-friction base-isolated structure were analyzed. Results show that the inter-story displacement, inter-story shear force and acceleration at lower layers are increased, but the response value at topper layers and the maximum displacement at isolated layer are less affected. The maximum displacement at isolated layer is mainly affected by frictional coefficient, sort condition and earthquake intensity.

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