The Influence of Isolator Hysteresis on Equipment Performance in Seismic Isolated Buildings

2010 ◽  
Vol 26 (1) ◽  
pp. 275-293 ◽  
Author(s):  
T. Y. Yang ◽  
Dimitrios Konstantinidis ◽  
James M. Kelly
Keyword(s):  
United States ◽  
Seismic Isolation ◽  
The United States ◽  
Large Displacements ◽  
Isolation System ◽  
Seismic Input ◽  
Alternative Approach ◽  
Moderate Earthquake ◽  
Time Histories ◽  
Isolation Systems

The seismic isolation code which must be used for all seismic isolated buildings in the United States is conservative in many of its provisions. While seismic isolation is flourishing in other countries, it is underused in the United States. For static analysis and for the selection of time histories, the spectrum is constant-velocity for periods of one second and longer, leading to large displacements for long period systems and forcing the designer to use added damping to reduce these displacements. The damping systems used are hysteretic with the characteristic that damping decreases with increasing displacement. To achieve the damping needed to reduce these large displacements, expected from very rare seismic input, means that at smaller displacements, caused by realistic levels of seismic input, the damping will be very much higher, and there may be stiffening of the isolation system, meaning that the building may not act as isolated and there may be an impact on sensitive internal equipment. This paper shows how highly damped isolation systems are counterproductive to isolation and suggests an alternative approach that will conform to code requirements but ensure that, at moderate earthquake inputs, the equipment remains protected, and the large code-mandated displacements are kept to acceptable levels.

Engineered Components for Spent Fuel Radioactive Waste Isolation Systems—are They Technically Justified?

1981 ◽  
Vol 11 ◽  
Author(s):  
H. C. Burkholder
Keyword(s):  
United States ◽  
Radioactive Waste ◽  
Release Rate ◽  
The United States ◽  
Radioactive Waste Disposal ◽  
Radionuclide Transport ◽  
Spent Fuel ◽  
Isolation System ◽  
Waste Forms ◽  
Isolation Systems

In response to draft radioactive waste disposal standards, R&D programs have been initiated in the United States which are aimed at developing and ultimately using radionuclide transport-delaying (e.g., long-lived waste containers) and radionuclide transport-controlling (e.g., very low release rate waste forms) engineered components as part of the isolation system. Before these programs proceed significantly, it seems prudent to evaluate the technical justification for development and use of sophisticated engineered components in radioactive waste isolation.

Seismic Isolation: History, Application, and Performance—A World View

1990 ◽  
Vol 6 (2) ◽  
pp. 161-201 ◽  
Author(s):  
Ian G. Buckle ◽  
Ronald L. Mayes
Keyword(s):  
United States ◽  
New Zealand ◽  
Soviet Union ◽  
Seismic Isolation ◽  
Base Isolation ◽  
World View ◽  
The United States ◽  
Isolation System ◽  
Fixed Base ◽  
Practical Reality

The concept of seismic or base isolation as a means of earthquake protection seems to be more than 100 years old. However, until very recently, few structures were built using this principle. Today the concept has matured into a practical reality and is taking its place as a viable alternate to conventional (fixed base) seismic resistant construction. This paper reviews some of the history of isolation and restates the basic elements of a modern isolation system. It then proceeds to review current activity, worldwide. Progress in the United States is discussed first followed by that in China, France, Greece, Italy, Japan, New Zealand and the Soviet Union. Directories of isolated structures in the United States, New Zealand and Japan are also included. Finally the performance of a selection of these structures during actual earthquakes is given.

scholarly journals RECENT DEVELOPMENT IN SEISMIC ISOLATION IN THE UNITED STATES*

1999 ◽  
pp. 57 ◽  
Author(s):  
J.M. Kelly
Keyword(s):  
United States ◽  
Seismic Isolation ◽  
Large Earthquake ◽  
Highway Bridges ◽  
The United States ◽  
Test Facility ◽  
Test Machine ◽  
Isolation Systems ◽  
The Cost ◽  
Year 2000

The first seismically isolated building in the United States was completed in 1985. In the fourteen years since then, a total of not more that twenty-five new buildings and twenty-two retrofits of existing buildings hass been completed. In constrast, the number of base-isolated building in Japan completed over the same time period is of the order of a few hundred, and in China, where the first isloated building was completed in 1995, there are now over seventy base-isolated building.Currently there are several building codes that govern the desing of base-isolated buildings in the United States. New regulations have been prepared for the year 2000 and beyond, which are both complex and conservative, discouraging the use of seismic isolation. These codes require the engineer to desing isolators for very large displacements and mandate extensive prototype and production testing, thereby restricting isolation's application to special structures such as hospitals and emergency service centers where a requirement for operational functionality following large earthquake events justifies the cost premium and time delays associated with the use of seismic isolation.Conversely, seismic isolation is widely used throughout the United States for highway bridges and is governed by a single desing code that is simple tob use and not overly conservative. Isolation systems are being used for the retrofit of several very large bridges in California. The isolators to be used for this projects are very large, and a test machine at the University of California, San Diego (UCSD), has just been completed to test these Isolators at full-scale, real-time rates.This paper will describe the current regulatory evironment for seismic isolation and the testing requirements for isolators. A description of the new test facility at UCSD will be included. 

Seismic Isolation Analysis on Long-Span Platform Bridge Connecting Twin-Tower Structures

2011 ◽  
Vol 255-260 ◽  
pp. 1225-1229
Author(s):  
Huang Sheng Sun ◽  
Li Nuo Cheng ◽  
Shi Hai Chen
Keyword(s):  
Seismic Isolation ◽  
Seismic Responses ◽  
One Pot ◽  
Isolation System ◽  
High Position ◽  
Long Span ◽  
Steel Truss ◽  
Story Drift ◽  
Isolation Systems ◽  
Rubber Bearings

In order to mitigate the seismic response of twin-tower structure linked by a steel truss platform bridge, as well as to reduce temperature force in the steel truss, eight groups of combined isolation system, each consisting of one pot-type bearing and four rubber bearings, were designed to connect the upper platform bridge to the lower supporting reinforced concrete towers. The features and working principles of the high-position isolation system were described. Then the seismic responses, including displacement, story drift and floor acceleration, of the structure with the isolation systems were calculated and compared with those of the structure with hinge joints in lieu of isolation. It is found that both the structural seismic responses and the temperature forces in the large-span mega-truss structure can be reduced by the high-position isolation system.

Book Reviews

2016 ◽  
Vol 54 (1) ◽  
pp. 243-246
Keyword(s):  
United States ◽  
Real World ◽  
Value Added ◽  
The United States ◽  
University Of California ◽  
Value Added Tax ◽  
Alternative Approach ◽  
Different Types ◽  
The Many

Roger H. Gordon of University of California, San Diego reviews “The Rise of the Value-Added Tax”, by Kathryn James. The Econlit abstract of this book begins: “Explores the evolution of the value-added tax (VAT) from relative obscurity to one of the world's most dominant revenue systems, why countries have adopted the VAT, and why different countries adopt different types of VAT. Discusses the rise of the value-added tax; an introduction to the good VAT; an introduction to the many real VATs in existence; the conventional approach to explaining the rise of the VAT; moving toward an alternative approach to explaining the rise of the VAT; case studies on the real-world challenges of VAT reform in Australia and the United States; and conclusions on the rise of the value-added tax.”

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 3 — Seismic Response of Crossover Piping for Seismic Isolation System

2014 ◽  
Author(s):  
Akihito Otani ◽  
Teruyoshi Otoyo ◽  
Hideo Hirai ◽  
Hirohide Iiizumi ◽  
Hiroshi Shimizu ◽  
...  
Keyword(s):  
Seismic Response ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Response Spectrum ◽  
Time History ◽  
Response Analysis ◽  
Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper, which is part of the series entitled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”, shows the linear seismic response of crossover piping installed in a seismically isolated plant. The crossover piping, supported by both isolated and non-isolated buildings, deforms with large relative displacement between the two buildings and the seismic response of the crossover piping is caused by two different seismic excitations from the buildings. A flexible and robust structure is needed for the high-pressure crossover piping. In this study, shaking tests on a 1/10 scale piping model and FEM analyses were performed to investigate the seismic response of the crossover piping which was excited and deformed by two different seismic motions under isolated and non-isolated conditions. Specifically, as linear response analysis of the crossover piping, modal time-history analysis and response spectrum analysis with multiple excitations were carried out and the applicability of the analyses was confirmed. Moreover, the seismic response of actual crossover piping was estimated and the feasibility was evaluated.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 4 — Failure Behavior of Crossover Piping for Seismic Isolation System

2014 ◽  
Author(s):  
Teruyoshi Otoyo ◽  
Akihito Otani ◽  
Shunsuke Fukushima ◽  
Masakazu Jimbo ◽  
Tomofumi Yamamoto ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Low Cycle Fatigue ◽  
Response Analysis ◽  
Failure Behavior ◽  
Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems ◽  
Failure Location

This paper provides a part of the series titled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”. This part shows the failure behavior of crossover piping installed in a seismic isolated plant. The considered crossover piping is supported on one side by an isolated building and by a non-isolated building on the other side. During an earthquake, the piping structure is deformed due to the large relative displacements between the two buildings and at the same time excited by the different building seismic responses. Therefore, the high-pressure crossover piping structure requires both flexibility and strength. In this study, 1/10 scaled shaking tests and FEM analyses have been performed to investigate the failure behavior of the crossover piping, where both seismic motions and excitations have been taken into account. It was confirmed that the failure occurs at the piping elbow through low cycle fatigue. Moreover, the results of the elastic-plastic response analysis, which simulates an extreme level of excitation corresponding to more than three times the design level, are in good agreement with the test results. The simulation also succeeded in predicting the experimental failure location.

The balance principle and the Reynolds transport theorem in introductory fluid mechanics

2017 ◽  
Vol 46 (3) ◽  
pp. 195-209
Author(s):  
Donald D Gray ◽  
Wade W Huebsch
Keyword(s):  
United States ◽  
Fluid Dynamics ◽  
Fluid Mechanics ◽  
Control Volume ◽  
The United States ◽  
Balance Principle ◽  
Alternative Approach ◽  
Finite Control ◽  
Transport Theorem ◽  
Volume Equations

This paper traces the evolution of the use of the Reynolds transport theorem to derive finite control volume equations for mass, momentum, and energy in introductory engineering fluid mechanics textbooks used in the United States. The paper demonstrates the superior merits of an alternative approach using the balance principle. The balance principle is easier to teach, to understand, and to apply in more complex situations. It better prepares students to understand the derivation of the partial differential equations of fluid mechanics and the finite volume equations of computational fluid dynamics. For these reasons, instructors should consider using the balance principle instead of (or at minimum in addition to) the Reynolds transport theorem in introductory fluid mechanics courses.

scholarly journals Multiclinic Observations on the Simplified Diet in PKU

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Laurie Bernstein ◽  
Casey Burns ◽  
Melissa Sailer-Hammons ◽  
Angela Kurtz ◽  
Frances Rohr
Keyword(s):  
United States ◽  
Inborn Error ◽  
Food Choices ◽  
The United States ◽  
Healthy Food ◽  
Inborn Error Of Metabolism ◽  
Neurocognitive Deficits ◽  
Restricted Diet ◽  
Blood Concentrations ◽  
Alternative Approach

Phenylketonuria is an inborn error of metabolism that historically has been treated with a strict phenylalanine-restricted diet where all foods are weighed and measured. This is cumbersome and difficult for patients and caregivers, especially patients with high phenylalanine blood concentrations who often have neurocognitive deficits. The Simplified Diet is an alternative approach that allows for increased flexibility, promotes healthy food choices, and is easier to manage than a traditional diet for PKU. This paper describes the implementation of the Simplified Diet and outlines education, counseling strategies, and challenges encountered by three metabolic clinics in the United States.

Rating Marketing Faculties on the Basis of Editorial Review Board Memberships

1988 ◽  
Vol 10 (1) ◽  
pp. 64-68 ◽  
Author(s):  
David L. Kurtz ◽  
Louis E. Boone
Keyword(s):  
United States ◽  
Traditional Approach ◽  
The United States ◽  
Colleges And Universities ◽  
Faculty Members ◽  
Alternative Approach ◽  
Academic Publications ◽  
Editorial Review

This article presents an alternative approach to evaluating marketing faculties in colleges and universities throughout the United States. The authors have made this assessment on the basis of editorial review board memberships rather than the more traditional approach of counting the number of academic publications by faculty members. This evaluative technique, originally presented in the finance literature, provides an interesting contrast to existing studies.

Sign in / Sign up

Export Citation Format

Share Document