Study on Small-Scale Laminated Type Base Isolation Device Using Urethane Elastomer for Practical Application

2016 ◽  
Author(s):  
Kenta Ishihana ◽  
Osamu Furuya ◽  
Kengo Goda ◽  
Shohei Omata
Keyword(s):  
Seismic Isolation ◽  
Mechanical Characteristics ◽  
Base Isolation ◽  
Small Scale ◽  
Loading Test ◽  
Isolation System ◽  
Seismic Safety ◽  
Base Isolation System ◽  
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 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. The mechanical characteristics based on the loading test up to 500% shear strain using experimental specimen with 100 × 100 mm cross-sectional shape. 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. 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.

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.

Study on Laminated Type Base Isolation Device Using Urethane Erastomer for Practical Application

2015 ◽  
Author(s):  
Kenta Ishihana ◽  
Osamu Furuya ◽  
Kengo Goda ◽  
Shohei Omata
Keyword(s):  
Mechanical Characteristics ◽  
Base Isolation ◽  
Approximate Expression ◽  
Response Analysis ◽  
Loading Test ◽  
Cross Sectional ◽  
Isolation System ◽  
Seismic Safety ◽  
Isolation Device ◽  
Urethane Elastomer

Base isolation system 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 this study, the research and development of laminated type base isolation device using urethane elastomer has been carried out to upgrade a seismic safety for various structures. The fundamental characteristics have been 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. Moreover, the experimental examination for aged deterioration in the urethane material has been continuously carried out. This paper summarizes the mechanical characteristics based on the loading test up to 500% shear strain using experimental specimen with 100×100 mm cross-sectional shape, base isolation effect from time response analysis using nonlinear element model of urethane elastomer and the accelerated aging test for verifying the aging of practical use.

Three Dimensional Seismic Isolation System for Next-Generation Nuclear Power Plant With Rolling Seal Type Air Spring and Hydraulic Rocking Suppression System

2005 ◽  
Author(s):  
Takahiro Shimada ◽  
Junji Suhara ◽  
Kazuhiko Inoue
Keyword(s):  
Dynamic Loading ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Three Dimensional ◽  
Loading Test ◽  
Isolation System ◽  
Ability Test ◽  
Base Isolation System ◽  
Suppression System

Three dimensional (3D) seismic isolation devices have been developed to use for the base isolation system of the heavy building like a nuclear reactor building. The developed seismic isolation system is composed of rolling seal type air springs and the hydraulic type springs with rocking suppression system for vertical base isolation device. In horizontal direction, the same laminated rubber bearings are used as horizontal isolation device for these systems. The performances and the applicability have already been evaluated by the technical feasibility tests and performance tests for each system. In this study, it was evaluated that the performance of the 3D base isolation system with rolling seal type air springs combined with hydraulic rocking suppression devices. A 1/7 scaled model of the 3D base isolation devices were manufactured and some performance test were executed for each device. For the rolling seal type air springs, dynamic loading test was executed with a vibration table, and pressure resistant ability test was executed for reinforced air springs. In the dynamic loading test, it is confirmed that the natural period and damping performance were verified. In the pressure resistant ability test, it is confirmed that the air springs had sufficient strength. For the hydraulic rocking suppression system, forced dynamic loading test was carried out in order to measure the frictional and oil flow resistance force on each cylinder. And the vibration table tests were carried out with supported weight of 228 MN in order to evaluate and to confirm the horizontal and vertical isolation performance, rocking suppression performance, and the applicability of the this seismic isolation system as the combined system. 4 rolling seal type air springs and 4 hydraulic load-carrying cylinders with rocking suppression devices supported the weight. As a result, the proposed system was verified that it could be applied to the actual nuclear power plant building to be target.

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.

Research and Development of Damping Device for Light Weight Mechanical Structure Using Damping Effect Caused by Eddy Current

2009 ◽  
Author(s):  
Osamu Furuya ◽  
Keiji Ogata ◽  
Toyohiko Tanaka ◽  
Hiroshi Kurabayashi
Keyword(s):  
Eddy Current ◽  
Base Isolation ◽  
Low Cost ◽  
Control Technique ◽  
Small Scale ◽  
Light Weight ◽  
Isolation System ◽  
Seismic Safety ◽  
Damping Effect ◽  
Kobe Earthquake

A base-isolation and vibration control technique has been applied positively to architectural and civil structures after Kobe earthquake, and now the techniques are adopted as general vibration reduction technique for many structures. In such situation, an application of the vibration attenuation device to the small-scale structure has been carried out actively in recent years. Especially, in the important institution of the cities such as a refuge place, a hospital, a school, an information and a communication institution where function maintenance is needed, it is important to maintain its performance of the machinery and equipment in the facility with an upgrade of structural seismic safety. Moreover, in the future, upgrading of seismic safety of the particular equipments is urgent business. This study has been examined a low cost and compact damping device for base-isolation system of light weight mechanical structures like a computer server rack. In this paper, the experimental and analytical results on the basic performances of the damping device using damping effect by Eddy-Current.

A study on seismic isolation of building used LRB

2020 ◽  
Vol 6 (2) ◽  
pp. 52
Author(s):  
Muhammet Yurdakul ◽  
Mehmet Burak Yıldız
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Dynamic Loads ◽  
Isolation System ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Earthquake Design ◽  
Base Isolation System ◽  
Internal Forces ◽  
Storey Building

Base isolation system with lead rubber bearing (LRB) is commonly used to prevent structure against to damage of earthquake. Design of LRB system is detailed in this study. The isolated building with LRB design according to Uniform Building Code (UBC-97) and fixed building were examined. The six-storey building with LRB and fixed building were modelled in SAP2000 with the same dynamic loads. The relative floor displacement and internal forces of the seismic isolated and fixed building are compared. In addition, transverse and longitudinal reinforcement of any axis of seismic isolated and fixed building are compared. Analyse results showed that effectiveness of using seismic isolation system on building. The weight of longitudinal and transverse reinforcement of isolated building is smaller than fixed building about 36%, 40% respectively.

scholarly journals Seismic Base Isolation System using Scrap Old Tyres

2020 ◽  
Vol 5 (3) ◽  
pp. 85-90
Keyword(s):  
Seismic Isolation ◽  
Structural Engineering ◽  
Base Isolation ◽  
Shock Propagation ◽  
Analysis Tool ◽  
Element Analysis ◽  
Isolation System ◽  
Isolation Technique ◽  
Base Isolation System ◽  
Seismic Vibrations

Enfeebling the effects of vibration caused by the movement of tectonic plates has been the major topic of research in the field of Structural Engineering. Base isolation is a technique used to counteract the effects of seismic vibration and ensuring the safety of the superstructure. Even though, the strategy of base isolation has been used in interminable number of structures, there is a need for economized, effective base isolation technique. India has been recycling and reusing waste tyres for four decades, it is estimated that 60% are disposed of through illegal dumping. India, being the second largest manufacturer of rubber after China, there is a menace of rubber disposal in the country. Despite the numerous efforts of technologists of recycling and utilizing the scrap rubber tyres, 17% of the scrap rubber tyres are diverted to landfill creating disposal problem. Therefore, there is a need for utilizing the used scrap rubber tyres in an innovative way instead of dumping it. Scrap Rubber tyres, being elastic in nature serve to be a potential shock absorber of seismic vibrations. In the present study, an attempt is made to utilize the recycled scrap rubber tyre in seismic isolation of structure. This technique proves to be a low- cost earthquake mitigation technique which can potentially reduce the damage caused by seismic shock propagation into the structure and hence ensure overall safety of the structure. An experimental analysis is done to evaluate the properties of assembly of rubber tyres and utilization of the same for isolating base of structures to check for the effectiveness in enfeebling the shocks produced by seismic vibrations. Furthermore, using the properties of scrap rubber tyres obtained from the experimental results, performance of the scrap tyres as a base isolation system for a multistoried building and stability of the structure was studied using Finite element analysis tool.

Development of a Seismic Isolation System for Commercial Storage Racks

2012 ◽  
Author(s):  
David H. Johnson ◽  
Robert J. Michael ◽  
Michael C. Pollino ◽  
Joseph D. Redovan ◽  
Eric E. Moser ◽  
...  
Keyword(s):  
Structural Damage ◽  
Seismic Isolation ◽  
Structural Engineering ◽  
Base Isolation ◽  
Earthquake Simulation ◽  
Element Analysis ◽  
Isolation System ◽  
Finite Element Analysis Simulation ◽  
Base Isolation System ◽  
Storage Racks

This paper provides an overview of an analysis performed on a new base isolation system developed for seismic isolation of steel pallet storage racks. Pallet storage racks are often found in warehousing for material storage and are designed to store materials on pallets in horizontal rows with multiple levels which are accessed by forklift trucks. The new isolation system provides seismic isolation in the cross-aisle direction by incorporating heavily damped elastomeric bearings (referred to here as seismic mounts) and low-friction bearing plates. The objective of the base isolation system is to reduce horizontal accelerations of the rack to eliminate product shedding and structural damage during a major earthquake without interfering with normal, day-to-day material handling operations. The paper presents a summary of numerical results (transient structural, finite element analysis simulation) comparing storage rack response against actual tests performed on a triaxial shake table in the Structural Engineering and Earthquake Simulation Laboratory (SEESL) at the University at Buffalo (see Filiatrault[1] et al. 2008 for comprehensive test details). The simulation model was then used to determine a set of optimal seismic isolation parameters that satisfy the practical range of rack shelf loads and configurations that can be expected in typical warehouse and store installations.

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