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Active structural control by fuzzy logic rules: An introduction

Description: A zeroth level introduction to fuzzy logic control applied to the active structural control to reduce the dynamic response of structures subjected to earthquake excitations is presented. It is hoped that this presentation will increase the attractiveness of the methodology to structural engineers in research as well as in practice. The basic concept of the fuzzy logic control are explained by examples and by diagrams with a minimum of mathematics. The effectiveness and simplicity of the fuzzy l… more
Date: December 1996
Creator: Tang, Yu & Wu, Kung C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Active vibration control of civil structures

Description: This is a final report of a one year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Active vibration control (AVC) of structural and mechanical systems is one of the rapidly advancing areas of engineering research. The multifaceted nature of AVC covers many disciplines, such as sensors and instrumentation, numerical modeling, experimental mechanics, and advanced power systems. This work encompassed a review of the literature on active … more
Date: November 1, 1996
Creator: Farrar, C.; Baker, W.; Fales, J. & Shevitz, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Character and origins of ground rupturing and ground deformation during the 28 June 1992 Landers, California earthquake (as well as the 1989 Loma Prieta and 1994 Northridge earthquakes). Final report

Description: The overall objective of the research has been to understand the form and significance of surface rupture produced by earthquakes. Specific objectives are to describe fracturing and other manifestations of broad belts of ground rupture during the Landers earthquake and to mechanically analyze the structures that form along the belts. The author has learned much about ground rupture during earthquakes, even though he has studied only three earthquakes to date: Loma Prieta, Landers and Northridge. more
Date: September 17, 1996
Creator: Johnson, A.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Damage from the impacts of small asteroids

Description: The fragmentation of a small asteroid in the atmosphere greatly increases its aerodynamic drag and rate of energy dissipation. The differential atmospheric pressure across it disperses its fragments at a velocity that increases with atmospheric density and impact velocity and decreases with asteroid density. Extending our previous work, we use a spherical atmosphere and a fitted curve to its density profile to find the damage done by an asteroid entering the atmosphere at various zenith angles.… more
Date: August 15, 1996
Creator: Hills, J.G. & Goda, M.P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Design and utilization of a portable seismic/acoustic calibration system

Description: Empirical results from the current GSETT-3 illustrate the need for source specific information for the purpose of calibrating the monitoring system. With the specified location design goal of 1,000 km{sup 2}, preliminary analysis indicates the importance of regional calibration of travel times. This calibration information can be obtained in a passive manner utilizing locations derived from local seismic array arrival times and assumes the resulting locations are accurate. Alternatively, an act… more
Date: October 1, 1996
Creator: Stump, B.W. & Pearson, D.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The development of enhanced ripple-fire identification methods using high frequency data from Pinedale

Description: A technique called ripple fire used in quarry blasts produces modulations in the spectra of these events. The Deployable Seismic Verification System (DSVS) was installed at the Pinedale Seismic Research Facility in Wyoming, an area with a lot of mining activity. DSVS records at frequencies up to 50 Hz and these data provides us with a unique opportunity to determine how well we can discriminate quarry blasts and if there are operational benefits from using high frequency (>20 Hz) data. We have … more
Date: January 1, 1996
Creator: Carr, D. & Garbin, H.D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Discriminating ripple-fire explosions with high frequency (>20 Hz) data

Description: With a Comprehensive Test Ban (CTB), discriminating ripple-fired explosions from mining operations becomes important. Different methods have been proposed to discriminate these explosions, most of which use the modulations seen in the spectra of ripple-fired blasts. The Deployable Seismic Verification System (DSVS) in Wyoming records data at frequencies up to 50 Hz, and provides an opportunity to determine if there are any operational benefits to discriminate ripple-fired explosions from using … more
Date: April 1, 1996
Creator: Carr, D. B. & Garbin, H.D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Earthquake early warning system using real-time signal processing

Description: An earthquake warning system has been developed to provide a time series profile from which vital parameters such as the time until strong shaking begins, the intensity of the shaking, and the duration of the shaking, can be derived. Interaction of different types of ground motion and changes in the elastic properties of geological media throughout the propagation path result in a highly nonlinear function. We use neural networks to model these nonlinearities and develop learning techniques for… more
Date: February 1, 1996
Creator: Leach, Jr., R. R. & Dowla, F. U.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Evaluation and analysis of the performance of masonary infills during the Northridge earthquake

Description: Observations were made of the behavior of masonry infills in structural frames during the Northridge earthquake, and an analytical technique was developed for analyzing infilled frame structures. Infills near the epicenter suffered significant damage, but in several cases contributed to the seismic resistance and life safety performance. Older infill buildings in downtown Los Angeles experienced intensity of shaking similar to that expected in central/eastern United States earthquakes. The infi… more
Date: February 1, 1996
Creator: Bennett, R. M.; Fischer, W. L.; Flanagan, R. D. & Tenbus, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

An evaluation of generalized likelihood Ratio Outlier Detection to identification of seismic events in Western China

Description: The Generalized Likelihood Ratio Outlier Detection Technique for seismic event identification is evaluated using synthetic test data and frequency-dependent P{sub g}/L{sub g} measurements from western China. For most seismic stations that are to be part of the proposed International Monitoring System for the Comprehensive Test Ban Treaty, there will be few or no nuclear explosions in the magnitude range of interest (e.g. M{sub b} < 4) on which to base an event-identification system using tradit… more
Date: September 24, 1996
Creator: Taylor, S. R. & Hartse, H. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ground motion input in seismic evaluation studies

Description: This report documents research pertaining to conservatism and variability in seismic risk estimates. Specifically, it examines whether or not artificial motions produce unrealistic evaluation demands, i.e., demands significantly inconsistent with those expected from real earthquake motions. To study these issues, two types of artificial motions are considered: (a) motions with smooth response spectra, and (b) motions with realistic variations in spectral amplitude across vibration frequency. Fo… more
Date: July 1, 1996
Creator: Sewell, R. T. & Wu, S. C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ground motion input in seismic evaluation studies: impacts on risk assessment of uniform hazard spectra

Description: Conservatism and variability in seismic risk estimates are studied: effects of uniform hazard spectrum (UHS) are examined for deriving probabilistic estimates of risk and in-structure demand levels, as compared to the more-exact use of realistic time history inputs (of given probability) that depend explicitly on magnitude and distance. This approach differs from the conventional in its exhaustive treatment of the ground-motion threat and in its more detailed assessment of component responses t… more
Date: July 1, 1996
Creator: Wu, S. C. & Sewell, R. T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Impact of ground motion characterization on conservatism and variability in seismic risk estimates

Description: This study evaluates the impact, on estimates of seismic risk and its uncertainty, of alternative methods in treatment and characterization of earthquake ground motions. The objective of this study is to delineate specific procedures and characterizations that may lead to less biased and more precise seismic risk results. This report focuses on sources of conservatism and variability in risk that may be introduced through the analytical processes and ground-motion descriptions which are commonl… more
Date: July 1, 1996
Creator: Sewell, R. T.; Toro, G. R. & McGuire, R. K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Impact of structural aging on seismic risk assessment of reinforced concrete structures in nuclear power plants

Description: The Structural Aging Program is addressing the potential for degradation of concrete structural components and systems in nuclear power plants over time due to aging and aggressive environmental stressors. Structures are passive under normal operating conditions but play a key role in mitigating design-basis events, particularly those arising from external challenges such as earthquakes, extreme winds, fires and floods. Structures are plant-specific and unique, often are difficult to inspect, a… more
Date: March 1996
Creator: Ellingwood, B. & Song, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Independent seismic evaluation of the 24-580-980 south connector ramps response to the south connector ramps to a magnitude 7.25 Hayward Fault earthquake. Volume 3

Description: The 24/580/980 interchange is located near Oakland California on the Eastern perimeter of the San Francisco Bay (Fig. 1 and Fig. 2). This interchange is a major artery in the Eastern San Francisco Bay area and provides a critical link between major bay area highways. The main Concord line of the Bay Area Rapid Transit System (BART), with ridership of approximately 270,000 per day, runs underneath the interchange. The interchange site is approximately 4 Km from the Hayward fault and 16 Km from t… more
Date: November 1996
Creator: McAllen, David B.; Gerhard, Michael A.; Trummer, David J. & Murray, Robert C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Mitigation of earthquake hazards using seismic isolation systems

Description: This paper describes mitigation of earthquake hazards using seismic base isolation systems. A numerical algorithm for analyzing system response of base-isolated structures with laminated elastomer bearings is briefly described. Seismic response analyses of both base- isolated and unisolated buildings under earthquakes {number_sign}42 and {number_sign}44 are performed and the results are compared to illustrate the mitigating effect of base-isolated systems.
Date: June 1, 1996
Creator: Wang, C. Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Natural phenomena hazards design and evaluation criteria for Department of Energy Facilities

Description: The Department of Energy (DOE) has issued an Order 420.1 which establishes policy for its facilities in the event of natural phenomena hazards (NPH) along with associated NPH mitigation requirements. This DOE Standard gives design and evaluation criteria for NPH effects as guidance for implementing the NPH mitigation requirements of DOE Order 420.1 and the associated implementation Guides. These are intended to be consistent design and evaluation criteria for protection against natural phenomen… more
Date: January 1, 1996
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Natural phenomena hazards, Hanford Site, south central Washington

Description: This document presents the natural phenomena hazard (NPH) loads for use in implementing DOE Order 5480.28, Natural Phenomena Hazards Mitigation, at the Hanford Site in south-central Washington State. The purpose of this document is twofold: (1) summarize the NPH that are important to the design and evaluation of structures, systems, and components at the Hanford Site; (2) develop the appropriate natural phenomena loads for use in the implementation of DOE Order 5480.28. The supporting standards… more
Date: April 16, 1996
Creator: Tallman, A. M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Natural phenomena hazards performance categorization guidelines for structures, systems, and components

Description: The purpose of this standard is as follows: (a) To provide, for the purpose of Natural Phenomena Hazard (NPH) design and evaluation, criteria for selecting performance categories (PCs) of structures, systems, and components (SSCs) in accordance with the requirements specified in DOE Order 420.1 and the NPH Implementation Guide to DOE Order 420.1. (b) To recommend general procedures for consistent application of the above performance categorization criteria so that the Department of Energy (DOE)… more
Date: January 1, 1996
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Near-surface velocity modeling at Yucca Mountain using borehole and surface records from underground nuclear explosions

Description: The Department of Energy is investigating Yucca Mountain, Nevada as a potential site for commercial radioactive waste disposal in a mined geologic repository. One critical aspect of site suitability is the tectonic stability of the repository site. The levels of risk from both actual fault displacements in the repository block and ground shaking from nearby earthquakes are being examined. In particular, it is necessary to determine the expected level of ground shaking at the repository depth fo… more
Date: September 1, 1996
Creator: Durrani, B.A. & Walck, M.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Neotectonics and seismicity of the Clearlake region in northern California

Description: Geological, topographic, and seismic methods were used to locate faults in the vicinity of Clearlake in northern California. The geological method, which seeks faults as discontinuities in the lithotope, found faults in the Tertiary-Cretaceous rocks east of Burns Valley. The topographic method, which is used to produce Fault Evaluation Reports, found a very active fault zone, the Konocti Bay fault zone, south of Highlands arm. It also found some active faults north of Highlands arm, in the east… more
Date: April 1, 1996
Creator: Burns, K.L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Quantification of seismic liquefaction risk

Description: Explicit goals of acceptable risk for natural phenomena hazards (earthquake, extreme wind, and flood) have been established by the Department of Energy (DOE) 1994. Closely associated to the earthquake risk is the issue of seismically-induced liquefaction. Because deterministic methods currently available to answer the question to whether a site is liquefiable or not are incapable of providing a clue as to the likelihood or risk of liquefaction, the application of the criteria to a given facilit… more
Date: February 29, 1996
Creator: Arango, I.; Ostadan, F.; Lewis, M. R. & Gutierrez, B. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Quarterly seismic monitoring report 96B

Description: This report summarizes the location, magnitude, and other pertinent information on earthquakes recorded on and near the Hanford Site by Westinghouse Seismic Monitoring during the period encompassing January 1, 1996 to March 31, 1996.
Date: June 12, 1996
Creator: Reidel, S. P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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