Experimental Seismic Response of Base Isolated Pallet-Type Steel Storage Racks

2008 ◽  
Vol 24 (3) ◽  
pp. 617-639 ◽  
Author(s):  
Andre Filiatrault ◽  
Peter S. Higgins ◽  
Assawin Wanitkorkul ◽  
James A. Courtwright ◽  
Robert Michael
Keyword(s):  
Structural Damage ◽  
Seismic Isolation ◽  
Material Handling ◽  
Base Isolation ◽  
Shake Table Tests ◽  
Isolation System ◽  
Base Isolation System ◽  
The Cross ◽  
Design Earthquake ◽  
Storage Racks

This paper presents the results of uniaxial and triaxial shake table tests performed on directly anchored and base isolated steel pallet storage racks loaded with simulated and real merchandise. The new base isolation system provides seismic isolation in the cross-aisle direction of a rack only, while providing similar restraints as conventional bolted base plates in the down-aisle direction. The objective of the isolation in the cross-aisle direction is to reduce the horizontal accelerations of the rack in order to reduce content spillage and structural damage during a major seismic event, without interfering with normal material handling operations. Base isolation is not provided in the down-aisle direction since the range of down-aisle natural periods of typical rack structures is already similar to that of typical base isolated structures. The results of the seismic tests clearly demonstrated the improved structural performance of rack structures incorporating the new cross-aisle base isolation system. Cross-aisle absolute accelerations and interstory drifts of the base isolated rack structure were reduced considerably compared to the values measured in the same rack conventionally anchored at its base. The base isolation system also had an effect in reducing the down-aisle accelerations. The base isolated racks met the performance objectives recommended in the FEMA 460 document “Seismic Considerations for Steel Storage Racks Located in Areas Accessible to the Public” both for life safety under the Design Earthquake (DE) and for collapse prevention under the Maximum Considered Earthquake (MCE).

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.

Hysteresis Loops of Base Isolation System - An Overview

2021 ◽  
Vol 879 ◽  
pp. 189-201
Author(s):  
M.A. Amir ◽  
N.H. Hamid
Keyword(s):  
Earthquake Engineering ◽  
Structural Damage ◽  
Base Isolation ◽  
Numerical Models ◽  
Hysteresis Loops ◽  
Human Beings ◽  
Rc Buildings ◽  
Isolation System ◽  
Base Isolation System ◽  
Isolation Systems

Recently, there are a lot of technological developments in the earthquake engineering field to reduce structural damage and one of them is a base isolation system. The base isolation system is one of the best technologies for the safety of human beings and properties under earthquake excitations. The aim of this paper is to review previous research works on simulation of base isolation systems for RC buildings and their efficiency in the safety of these buildings. Base isolation decouples superstructure from substructure to avoid transmission of seismic energy to the superstructure of RC buildings. The most effective way to assess the base isolation system for RC building under different earthquake excitations is by conducting experiment work that consumes more time and money. Many researchers had studied the behavior of base isolation system for structure through modeling the behavior of the base isolation in which base isolator is modeled through numerical models and validated through experimental works. Previous researches on the modeling of base isolation systems of structures had shown similar outcomes as the experimental work. These studies indicate that base isolation is an effective technology in immunization of structures against earthquakes.

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.

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.

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 Innovative Structural Solutions for Prefab Reinforced Concrete Hall-Type Buildings

2019 ◽  
Vol 13 (1) ◽  
pp. 149-163 ◽  
Author(s):  
Stefano Sorace ◽  
Gloria Terenzi
Keyword(s):  
Reinforced Concrete ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Seismic Protection ◽  
Isolation System ◽  
Fluid Viscous Dampers ◽  
Protection Strategies ◽  
Additional Costs ◽  
Design Earthquake ◽  
Bracing System

Background:The anti-seismic design of prefab reinforced concrete buildings is usually carried out with a conventional ductility-based approach. This implies a remarkable plastic demand on columns, as well as damages to the connections of structural and non-structural members, for seismic events with comparable intensity to the basic design earthquake normative level.Objective:In view of this, a study was developed and aimed at extending to the field of new prefab reinforced concrete structures the application of advanced seismic protection strategies, capable of guaranteeing undamaged response up to the maximum considered earthquake normative level.Method:A benchmark building was designed as demonstrative case study for this purpose, in the three following hypotheses: (a) according to a traditional ductility-based approach; (b) by incorporating dissipative bracings, equipped with fluid viscous dampers; (c) by placing a seismic isolation system at the base, composed of a set of double curved surface sliders.Results:The results of the verification analyses show that the targeted performance for the design solutions b) and c) is obtained with sizes of columns and plinths notably smaller than those for the conventional design. This allows compensating the additional cost related to the incorporation of the protective devices, for the dissipative bracing system, and limiting additional costs below 25%, for the base isolation solution. At the same time, a supplemental benefit of the latter is represented by greater protection of contents and plants, as they are fully supported by the seismically isolated ground floor.Conclusion:The study highlights the advantages offered by the two advanced seismic protection technologies in an unusual field of application, guaranteeing an enhanced performance of structural and non-structural elements, as well as reduced member sizes, as compared to the traditional ductility-based design.

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.

scholarly journals Evaluating Collapse Fragility Curves for Existing Buildings Retrofitted Using Seismic Isolation

2020 ◽  
Vol 10 (8) ◽  
pp. 2844
Author(s):  
Amedeo Flora ◽  
Giuseppe Perrone ◽  
Donatello Cardone
Keyword(s):  
Seismic Isolation ◽  
Failure Modes ◽  
Base Isolation ◽  
Fragility Curves ◽  
Limit State ◽  
Spectral Acceleration ◽  
Existing Buildings ◽  
Isolation System ◽  
Isolation Technique ◽  
Design Earthquake

Few studies have investigated so far the collapse capacity of buildings with base-isolation. In such studies, preliminary considerations have been drawn based on a number of assumptions regarding: (i) the methodology used for assessing the collapse capacity, (ii) the collapse conditions and failure modes assumed for both superstructure and isolation system, and (iii) the numerical modeling assumptions. The main results pointed out that the collapse conditions of base-isolated buildings may occur for intensity levels slightly higher than those associated with the design earthquake. In this paper, further developments are made through the use of enhanced models for the description of the behavior of a rubber-based isolation system and the assumption of more rational collapse conditions. Collapse fragility functions, in terms of mean and dispersion values, are proposed for two archetypes representative of existing buildings retrofitted using the seismic isolation technique. The collapse margin ratio (median collapse capacity Sa,C, namely the spectral acceleration associated to a probability of exceedance equal to 50%, divided by the design spectral acceleration at the collapse prevention limit state) has been evaluated for each examined case-study. Values ranging from 1.10 to 1.45 were found.

Sign in / Sign up

Export Citation Format

Share Document