bluuebunny/crossref_metadata_2025 huggingface dataset:
Insurance as an Integrating Policy Tool for Disaster Management: The Role of Public-Private Partnerships
Authors: Kunreuther Howard
Published: July 2003

Insurance can play a key role in facilitating public-private partnerships for dealing with the losses from future natural disasters. This paper proposes a hazard management program, which links insurance with other policy tools and brings together key interested parties concerned with earthquakes. It stresses the importance of identifying and assessing the risk, understanding both the decision processes of individuals in hazard-prone areas and the insurability issues associated with the earthquake risk. A series of policy-related questions raise issues for future research.
Seismic Retrofit and Repair of Circular Bridge Columns with Advanced Composite Materials
Authors: Ma R. , Xiao Yan
Published: July 2003

Experimental studies on seismic retrofit and repair of typical circular bridge columns with poor lap splice details utilizing prefabricated glass fiber reinforced polymer (FRP) composite jackets and epoxy are presented in this paper. A total of seven tests on three 1/2-scale model columns were conducted. One column was tested under “as-built” condition and the other two columns were retrofitted with prefabricated composite individual and continuous jackets respectively. The jackets were applied in the potential plastic hinge region of the column to increase its lateral confinement. Brittle failure was observed in the “as-built” model column due to the bond deterioration of lap spliced longitudinal reinforcement. This brittle failure was prevented in the retrofitted columns. The repairing of failed “as-built” column by injecting epoxy into damaged plastic region resulted in significant stiffening of the portion and increase of capacity and ductility. The second repair of the specimen using both epoxy injection and prefabricated composite jacketing effectively improved its behavior further. The results of this study indicated that dramatic improvement in ductility and energy absorption capacity of columns can be achieved using these retrofit and repair methods.
How Safe Are Pre-Northridge WSMFs? A Case Study of the SAC Los Angeles Nine-Story Building
Authors: Maison Bruce F. , Bonowitz David
Published: July 2003

This paper demonstrates a procedure for modeling, analysis, and evaluation of existing steel frame buildings of the type damaged in the 1994 Northridge earthquake. The procedure accounts for Northridge data and incorporates post-Northridge research. It is distinguished from more conventional procedures by the use of fracturing connection elements with randomly assigned rotation capacities. The study confirms and quantifies a number of observations from Northridge. Damage patterns are highly variable, but their global effects are predictable. Many steel frame buildings can sustain substantial damage and still satisfy criteria for “safe” response. Expected performance, however, is measurably less reliable than intended performance, and this has important implications for public policy and performance-based engineering.
Analysis and Design of Concrete Columns for Confinement
Authors: Razvi Salim R. , Saatcioglu Murat
Published: July 2003

An analytical procedure was developed to model formation and progression of flexural hinging in reinforced concrete columns. The procedure was employed to demonstrate second order inelastic analysis of concrete columns under monotonically increasing lateral loads. Other relevant features of inelastic column analysis were also incorporated, including concrete confinement, reinforcement strain hardening, bar buckling and anchorage slip. The analysis procedure has been verified extensively against experimental data, and used to illustrate a displacement-based design procedure for column confinement. Furthermore, a set of column analyses was conducted to develop design aids for column confinement. The amount, grade, spacing and arrangement of confinement reinforcement can be selected from these design aids for expected levels of lateral drift and axial compression.
Meeting the Challenges of Reducing Earthquake Losses: Engineering Accomplishments and Frontiers
Authors: Abrams Daniel P.
Published: July 2003

Accomplishments in earthquake engineering under the National Earthquake Hazards Reduction Program (NEHRP) have been numerous since the inception of the federal program in 1977 and are noted herein with a series of examples of former and present work done by NSF, FEMA, NIST and their investigators. These examples illustrate the implementation of research and development towards reducing earthquake losses, and include projects done to (a) better understand response of constructed facilities to earthquakes, (b) develop improved national standards and practices for planning, design and construction of earthquake resistant facilities, (c) develop methods for assessment of vulnerability of existing facilities to earthquake effects, and (d) develop methods for strengthening or repair of vulnerable facilities. Future frontiers in earthquake engineering research are also discussed including cross-disciplinary approaches of newly established national earthquake engineering research centers that are directed at minimizing losses to communities and national networks.
The Earthquake Industry
Authors: Reitherman Robert
Published: July 2003

A recent study of the ethical implications of working in the earthquake field featured three dozen ethical scenarios, most of which posed the issue of failing to disclose earthquake risks or inadequately promoting seismic risk reduction. In that study, a common ethical issue was never mentioned, namely that “the earthquake community” is also “the earthquake industry.” Most of us who work in the earthquake field have public interest and self-interest motives, and a full discussion of ethical issues requires that we talk about both.
USGS National Seismic Hazard Maps
Authors: Frankel A. D. , Mueller C. S. , Barnhard T. P. , Leyendecker E. V. , Wesson R. L. , Harmsen S. C. , Klein F. W. , Perkins D. M. , Dickman N. C. , Hanson S. L. , Hopper M. G.
Published: July 2003

The U.S. Geological Survey (USGS) recently completed new probabilistic seismic hazard maps for the United States, including Alaska and Hawaii. These hazard maps form the basis of the probabilistic component of the design maps used in the 1997 edition of the NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures, prepared by the Building Seismic Safety Council and published by FEMA. The hazard maps depict peak horizontal ground acceleration and spectral response at 0.2, 0.3, and 1.0 sec periods, with 10%, 5%, and 2% probabilities of exceedance in 50 years, corresponding to return times of about 500, 1000, and 2500 years, respectively. In this paper we outline the methodology used to construct the hazard maps. There are three basic components to the maps. First, we use spatially smoothed historic seismicity as one portion of the hazard calculation. In this model, we apply the general observation that moderate and large earthquakes tend to occur near areas of previous small or moderate events, with some notable exceptions. Second, we consider large background source zones based on broad geologic criteria to quantify hazard in areas with little or no historic seismicity, but with the potential for generating large events. Third, we include the hazard from specific fault sources. We use about 450 faults in the western United States (WUS) and derive recurrence times from either geologic slip rates or the dating of pre-historic earthquakes from trenching of faults or other paleoseismic methods. Recurrence estimates for large earthquakes in New Madrid and Charleston, South Carolina, were taken from recent paleoliquefaction studies. We used logic trees to incorporate different seismicity models, fault recurrence models, Cascadia great earthquake scenarios, and ground-motion attenuation relations. We present disaggregation plots showing the contribution to hazard at four cities from potential earthquakes with various magnitudes and distances.
Active Fault Near-Source Zones within and Bordering the State of California for the 1997 Uniform Building Code
Authors: Petersen Mark D. , Toppozada Tousson R. , Cao Tianqing , Cramer Chris H. , Reichle Michael S. , Bryant William A.
Published: July 2003

The fault sources in the Project 97 probabilistic seismic hazard maps for the state of California were used to construct maps for defining near-source seismic coefficients, Na and Nv, incorporated in the 1997 Uniform Building Code (ICBO 1997). The near-source factors are based on the distance from a known active fault that is classified as either Type A or Type B. To determine the near-source factor, four pieces of geologic information are required: (1) recognizing a fault and determining whether or not the fault has been active during the Holocene, (2) identifying the location of the fault at or beneath the ground surface, (3) estimating the slip rate of the fault, and (4) estimating the maximum earthquake magnitude for each fault segment. This paper describes the information used to produce the fault classifications and distances.
The Seismic Provisions of the 1997 Uniform Building Code
Authors: Bachman Robert E. , Bonneville David R.
Published: July 2003

Currently the most widely accepted code regulations in the United States for seismic design of structures and nonstructural components are those found in the Uniform Building Code ( UBC). The UBC seismic requirements were significantly revised in the 1997 edition. Among the issues addressed in the UBC revisions are near-source effects and ground acceleration dependent soil site amplification factors for both short- and long-period structures. Also, the design force levels in the 1997 UBC are based on strength design rather than allowable stress design, as had been used previously. Other significant changes include introduction of a redundancy/reliability factor, a more realistic consideration of story drift and deformation compatibility, and new equations for equivalent static forces for both structural and nonstructural components. This paper traces the recent history of the code development and describes the major elements of the 1997 UBC seismic provisions.
The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures
Authors: Holmes William T.
Published: July 2003

This paper follows the evolution of the NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures from the development of ATC 3-06 to the 1997 edition of the document. The features of the 1997 NEHRP Provisions are described in detail. Complementary information about the NEHRP Provisions is found in several other papers in this volume of Earthquake Spectra. Subject areas covered elsewhere are specifically referenced in this paper.
Nonbuilding Structures Seismic Design Code Developments
Authors: Sprague Harold O. , Legatos Nicholas A.
Published: July 2003

The building code development process has traditionally given little effort to developing the seismic design process of nonbuilding structures. This has created some unique problems and challenges for the structural engineers that design these types of structures. The intended seismic performance requirements for “building” design are based on life safety and collapse prevention. Structural elements in buildings are allowed to yield as a method of seismic energy dissipation. The seismic performance of nonbuilding structures varies depending on the specific type of nonbuilding structure. Nonlinear behavior in some nonbuilding structures is unacceptable while other nonbuilding structures may be allowed to yield during an earthquake. Nonbuilding structures comprise a vast myriad of structures constructed of all types of materials, with markedly different dynamic characteristics, and with a wide range of performance requirements. This paper discusses the development of codes, design practices, and future of the seismic design criteria for nonbuilding structures.
Major Changes in Concrete-Related Provisions-1997 UBC and Beyond
Authors: Ghosh S. K.
Published: July 2003

U.S. seismic codes are undergoing profound changes as of this writing. Changes from the 1994 to the 1997 edition of the Uniform Building Code (UBC) (ICBO 1994, 1997) are many and far-reaching in their impact. The 1997 edition of the National Earthquake Hazards Reduction Program (NEHRP) Recommended Provisions for Seismic Regulations for New Buildings (BSSC 1998) contains further evolutionary changes in seismic design requirements beyond those of the 1997 UBC. The latter document will form the basis of the seismic design provisions of the first edition of the International Building Code (IBC), to be published in the spring of 2000. This paper first discusses the major changes that have been made in the concrete-related provisions from the 1994 to the 1997 edition of the UBC. The paper gives background to these changes, provides essential details on them, and indicates how they have been or how they are going to be incorporated (at times with significant modifications) into the 1997 NEHRP Provisions and the 2000 IBC. The newly published ACI 318-99, Building Code Requirements for Structural Concrete (ACI 1999), is going to be adopted by reference into the 2000 IBC. This entails further changes in concrete-related provisions beyond the 1997 UBC. Some of the more important of these changes are discussed here. A small number of amendments and additions to the ACI 318-99 provisions are going to be included in the 2000 IBC. The more important of these are also outlined in this paper.
Seismic Design Guidelines and Provisions for Steel-Framed Buildings: FEMA 267/267A and 1997 AISC Seismic Provisions
Authors: Malley James O. , Carter Charles J. , Saunders C. Mark
Published: July 2003

One of the important surprises of the Northridge earthquake of January 17, 1994, was the widespread and unanticipated brittle fracture of welded steel beam-to-column connections. Although no casualties or collapses occurred during the Northridge earthquake as a result of these connection failures, and many WSMF buildings were not damaged at all, a wide spectrum of brittle connection damage did occur, ranging from minor cracking to completely severed columns. This paper summarizes two of the most important documents that have been developed in response to the damage suffered to steel moment frame buildings in the Northridge earthquake. The first, FEMA 267, Interim Guidelines: Evaluation, Repair, Modification and Design of Welded Steel Moment Frame Structures, was generated from studies undertaken as part of a project initiated by the U.S. Federal Emergency Management Agency (FEMA) to reduce the earthquake hazards posed by steel moment-resisting frame buildings. The second document addressed in this paper is the 1997 edition of the American Institute of Steel Construction (AISC) Seismic Provisions for Structural Steel Buildings (commonly referred to as the AISC Seismic Provisions) that incorporates the new information generated by the FEMA-sponsored project and other investigations on the seismic performance of steel structures, and has been adopted by reference into the 2000 International Building Code (IBC).
Seismic Design Requirements for Regions of Moderate Seismicity
Authors: Nordenson Guy J. P. , Bell Glenn R.
Published: July 2003

The need for earthquake-resistant construction in areas of low-to-moderate seismicity has been recognized through the adoption of code requirements in the United States and other countries only in the past quarter century. This is largely a result of improved assessment of seismic hazard and examples of recent moderate earthquakes in regions of both moderate and high seismicity, including the San Fernando (1971), Mexico City (1985), Loma Prieta (1989), and Northridge (1994) earthquakes. In addition, improved understanding and estimates of older earthquakes in the eastern United States such as Cape Ann (1755), La Malbaie, Quebec (1925), and Ossippe, New Hampshire (1940), as well as monitoring of micro-activity in source areas such as La Malbaie, have increased awareness of the earthquake potential in areas of low-to-moderate seismicity. Both the hazard and the risk in moderate seismic zones (MSZs) differ in scale and kind from those of the zones of high seismicity. Earthquake hazards mitigation measures for new and existing construction need to be adapted from those prevailing in regions of high seismicity in recognition of these differences. Site effects are likely to dominate the damage patterns from earthquakes, with some sites suffering no damage not far from others, on soft soil, suffering near collapse. A number of new seismic codes have been developed in the past quarter century in response to these differences, including the New York City (1995) and the Massachusetts State (1975) seismic codes. Over the same period, the national model building codes that apply to most areas of low-to-moderate seismicity in the United States, the Building Officials and Code Administrators (BOCA) Code and the Southern Standard Building Code (SSBC), have incorporated up-to-date seismic provisions. The seismic provisions of these codes have been largely inspired by the National Earthquake Hazard Reduction Program (NEHRP) recommendations. Through adoption of these national codes, many state and local authorities in areas of low-to-moderate seismicity now have reasonably comprehensive seismic design provisions. This paper will review the background and history leading up to the MSZ codes, discuss their content, and propose directions for future development.
Caltrans' New Seismic Design Criteria for Bridges
Authors: Yashinsky Mark , Ostrom Thomas
Published: July 2003

Caltrans' Seismic Design Criteria (SDC) has been adopted as the minimum seismic standard for ordinary bridges on California's highways. The SDC is a compilation of new and existing seismic criteria that had been previously documented in a variety of Caltrans documents. The SDC extends the capacity design philosophy introduced in the 1980 Caltrans Bridge Design Specifications. The most significant departure from the previous procedure is that ductile members are now designed by comparing the displacement demand to the displacement capacity. The demands are generated by a linear elastic analysis, and the capacities are determined from a curvature analysis that incorporates the nonlinear behavior of the structural elements. The demand/capacity methodology supplants the previous method based on reducing the elastic dynamic forces by a force reduction factor. In this paper, the significant features of Caltrans' SDC are described.
Seismic Behavior of Blocky Masonry Structures
Authors: Azevedo Joa~o , Sincraian Gabriela , Lemos J. V.
Published: July 2003

The seismic behavior of structures composed by masonry blocks is analyzed using the discrete element method. Some features of the method are described including the representation of the block deformation, contacts and block interaction. The suitability of the method for the analysis of masonry structures is examined. The seismic behavior of some simple structural systems as well as that of some real structures is studied. It is shown that the method is able to reproduce important phenomena such as crack opening and joint sliding, which are responsible for the occurrence of structural damage and collapse. The collapse patterns of the analyzed structures are examined, reinforcing schemes using steel cables are considered and seismic vulnerability functions are obtained.
Development of a Performance Evaluation Database for Concrete Bridge Components and Systems under Simulated Seismic Loads
Authors: Hose Yael , Silva Pedro , Seible Frieder
Published: July 2003

Through lessons learned in recent earthquakes, the need for new seismic bridge design methodologies that consider structural performance explicitly and address the inelastic response of bridge structures more directly is recognized. Efforts are in progress to define and quantify limit states and associated performance goals to develop a multi-level bridge design methodology. A multi-level design approach can only be implemented, however, when structural behavior or limit states can accurately be characterized and assessed for the wide range of probable input or demands. The outlined capacity assessment database addresses the response determination and parameterization of bridge components, sub-assemblages, and systems in direct support of the development of multi-level performance design and evaluation procedures for bridges. Through the use of a standardized template, a performance library for bridge structures, which is open for access and expansion to the entire practicing bridge engineering community, has been initiated.
Evaluation and Reduction of Liquefaction Potential at a Site in St. Louis, Missouri
Authors: Kumar Sanjeev
Published: July 2003

This paper presents results of seismic ground response and liquefaction analyses performed for a site located in the floodplain of the Missouri River in St. Louis, Missouri. Synthetic earthquake time histories and recorded ground motions from two earthquakes in Canada were used to perform the analyses. Synthetic time histories were generated using attenuation relationships for Central United States. The ground response analyses indicated that the ground motions at the site are likely to amplify by a factor between 1.4 and 2.25. From the liquefaction analysis it was concluded that the site had significant liquefaction potential. The site was remediated to reduce liquefaction potential using deep dynamic compaction. Modifications, in the form of construction of stone columns, were made to the conventional method of deep dynamic compaction to densify the soils to required depths. Results presented show that site remediation procedure used at the site successfully densified the site soils to desired densities. Construction of stone columns not only densified the in-place soils to deeper depths, but also helped to support relatively heavily loaded columns on spread footings. The project was completed on schedule with significant cost savings.
Practical Nonlinear Seismic Analysis of Tanks
Authors: Malhotra Praveen
Published: July 2003

Liquid-storage tanks, designed as per the minimum requirements of API Standard 650 (1996), AWWA Standard D100 (1996), or any other design standard, should not be expected to remain fully elastic, or undamaged, when subjected to design ground shaking. Forces prescribed in design standards are only a fraction of those obtained from a linear elastic (no damage) response analysis. Force reductions are based on the expected overstrength and ductility of the system. However, there are no practical methods to quantify the effects of these reductions on potential damage to tanks. Some type of nonlinear analysis is needed to assess the tank's desired performance objectives. This paper presents a simplified nonlinear analysis for performance-based seismic design of tanks. It also presents a method of strengthening tanks by energy-dissipating base anchors. The simplified nonlinear analysis is illustrated for an unanchored tank, a tank anchored with traditional anchors, and a tank anchored with energy-dissipating anchors.
Lessons of the 25 January 1999 Earthquake in Central Colombia
Authors: Sánchez-Silva Mauricio , Yamín Luis E. , Caicedo Bernardo
Published: July 2003

On January 25, 1999, an earthquake of magnitude ML = 6.1 occurred in central Colombia, which caused 1,200 deaths, 5,000 injuries, more than 250,000 people affected and economic losses estimated at US$1.2 billion. The earthquake left some important lessons that must be taken into account for the management of similar situations in the future. With respect to the behavior of buildings, the soundness and importance of the code of practice for buildings was demonstrated as a tool for the prevention of seismic disasters. The management of the emergency in cities such as Pereira and Armenia showed the need for planning, continued preparedness and mitigation awareness. The importance of the Colombian Prevention and Disaster Attention System (SNPAD) was demonstrated although the need to enhance organizational aspects, citizen awareness and participation was made evident. The characteristics of the disaster reflect a typical situation that can occur in many Latin American cities located in areas of high seismic risk. This article presents the main lessons learned from this event in the light of work performed by the research team for natural disasters from the Department of Civil and Environmental Engineering of the Universidad de Los Andes.
A Nonlinear Analysis Method for Performance-Based Seismic Design
Authors: Fajfar Peter
Published: July 2003

A relatively simple nonlinear method for the seismic analysis of structures (the N2 method) is presented. It combines the pushover analysis of a multi-degree-of-freedom (MDOF) model with the response spectrum analysis of an equivalent single-degree-of-freedom (SDOF) system. The method is formulated in the acceleration-displacement format, which enables the visual interpretation of the procedure and of the relations between the basic quantities controlling the seismic response. Inelastic spectra, rather than elastic spectra with equivalent damping and period, are applied. This feature represents the major difference with respect to the capacity spectrum method. Moreover, demand quantities can be obtained without iteration. Generally, the results of the N2 method are reasonably accurate, provided that the structure oscillates predominantly in the first mode. Some additional limitations apply. In the paper, the method is described and discussed, and it basic derivations are given. The similarities and differences between the proposed method and the FEMA 273 and ATC 40 nonlinear static analysis procedures are discussed. Application of the method is illustrated by means of an example.
Selective Control of Base-Isolated Structures with CS Dampers
Authors: Gluck J. , Ribakov Y. , Dancygier A. N.
Published: July 2003

Addition of dampers to a base isolator reduces base displacements but may increase floor accelerations and interstory drifts. This paper presents a “selective control approach” for the design of base-isolated active controlled structures with Controlled Stiffness Dampers (CSD). According to this approach the dampers are activated only within a given range of the base displacement. The optimal damping forces are calculated according to structure's displacements and velocities. However, because of the CS dampers' structure the actual application of the forces is independent of the displacement and the velocity that are transferred to the device. These forces depend only on the geometry and on the mechanical properties of the devices' springs. The efficiency of the proposed method is demonstrated in a numerical example.
Performance of Elevator Systems in the 22 November 1995 Gulf of Eilat-Aqaba Earthquake
Authors: Levy R. , Rutenberg A. , Magnus P. , Marianchik E. , Segal F.
Published: July 2003

The paper consists of two parts. The first part describes the results of a limited survey of damage to elevator systems during the 1995 Gulf of Eilat earthquake. The second part summarizes an analytical study on the seismic response of counterweight guide rails. The analytical part utilizes a mathematical model that the authors developed earlier, showing its effectiveness in guide rail design with reference to the damage revealed by the survey. Results clearly indicate that the rails that are commonly used in Israel cannot withstand earthquakes in the Eilat area (PGA = 0.2g). Facts observed in the field are verified analytically. The observation that very few rails were bent despite derailment of counterweight at weight levels of 1000 kg is noted. Practical recommendations and design charts for the commonly used rails in Israel are provided as well.
Assessment of Seismic Site Effects in 2-D Alluvial Valleys Using Neural Networks
Authors: Paolucci Roberto , Colli Pietro , Giacinto Giorgio
Published: July 2003

There is an increasing need to fill the gap between research and engineering practice as far as consideration of complex seismic site effects is concerned. To address this problem in an innovative way, we have developed a pattern recognition approach based on neural networks as a discriminant tool. The classification algorithm has been trained with the results of a large number of numerical simulations of the seismic response of 2-D layered valleys with both symmetric and asymmetric shape, using as excitation several real accelerograms. The different phases of the classification analysis are explored, namely: a) definition of the set of features (i.e., pattern attributes); b) definition of appropriate classes for discrimination of hazard levels; c) training of the neural network; d) interpretation of results using a structured neural network architecture and evaluation of the most critical features that govern the classification; e) validation of the trained network on real case histories. Among the most interesting conclusions of this study, is that the most relevant information for predicting the site-related hazard in a 2-D valley configuration is condensed in the local 1-D resonance frequency and the global 2-D resonance of the valley ( f01D and f02D). If one considers as features only f01D and f02D the performance of the classification tool is only slightly lower than that obtained using a larger set of features.
Analysis of Seismic Damage Patterns in Old Masonry Church Facades
Authors: Casolo Siro , Neumair Siegfried , Parisi Maria A. , Petrini Vincenzo
Published: July 2003

The semi-empirical assessment of seismic vulnerability of ancient church buildings is possible only if sufficient knowledge of the expected seismic behavior is available for a wide variety of typologies. For this reason, the information inferred from seismic damage observation may need to be complemented by numerical analysis. A simplified material model is proposed here for predicting the damage from out-of-plane behavior of large walls in old masonry churches subjected to seismic loading. For a specific substructure, the church façade, the effects of geometry, strength and post-elastic behavior of the material, as well as excitation characteristics are then analyzed with reference to the formation of a collapse mechanism. Comparison with observed damage thoroughly confirms the crack patterns developed numerically. Thence, the material model proposed may be considered satisfactory and suitable for use in seismic vulnerability studies.
Behavior and Design of Reinforced Concrete, Steel, and Steel-Concrete Coupling Beams
Authors: Harries Kent A. , Gong Bingnian , Shahrooz Bahram M.
Published: July 2003

The efficiency of coupled wall systems to resist lateral loads is well known. In order for the desired behavior of the coupled wall system to be attained, the coupling beams must be sufficiently strong and stiff. The coupling beams, however, must also yield before the wall piers, behave in a ductile manner, and exhibit significant energy-absorbing characteristics. This paper reviews the current state of the art for the design of conventional reinforced concrete, diagonally reinforced concrete, steel, and composite steel-concrete coupling beams. Although not exhaustive, critical aspects of the design of these systems are presented.
Review of Earthquake Performance, Seismic Codes, and Dynamic Analysis of Elevators
Authors: Suarez Luis E. , Singh Mahendra P.
Published: July 2003

Elevators are among the most important mechanical systems in building structures that are quite susceptible to earthquake-induced damages. This survey paper is written primarily for the earthquake engineers who have not been directly involved in the design and maintenance of elevator systems but who are professionally interested in their functioning and performance. It describes the important components of an elevator system and highlights those that are most susceptible to earthquake-induced ground motions. A comprehensive review of the observed performance of elevators in past earthquakes reported by many investigators in the open literature is also presented. The evolution of code provisions for seismic design of these systems, measures adopted by the industry to mitigate the seismic effects and enhance seismic performance, and rationale of simple formula used for the current designs of counterweight guide rails and their supports are reviewed. A comprehensive review of the technical studies conducted to examine the dynamic behavior of these studies is also presented.
Earthquake Damage Assessment Based on Fuzzy Logic and Neural Networks
Authors: Sánchez-Silva Mauricio , García Libardo
Published: July 2003

Potential damage assessment is fundamental for defining mitigation procedures and risk management strategies. Damage assessment involves the difficulties of defining, assessing, and modeling the variables involved, as well as handling uncertainty. Seismic damage estimation of structures does not only depend on the behavior of the structural system, but it involves other factors, which differ in nature. The paper presents a methodology for damage assessment of structures that combines systems theory, fuzzy logic, and neural networks. A feed-forward neural network supported on the systemic organization of information is used to assess the expected structural damage for a given earthquake. The methodology provides a very useful environment to consider the context of the building structure. The network has been trained using the damage observed in the recent earthquake that occurred in central Colombia. Several sets of structures were evaluated and the results compared to the damage observed. The model showed to be highly reliable and a good representation of experts' opinions. Computer software ERS-99 was developed and is currently being used for teaching and consulting purposes.
Probabilistic Seismic Hazard Analyses for Ground Motions and Fault Displacement at Yucca Mountain, Nevada
Authors:   Yucca Mountain PSHA Project Members, Stepp J. Carl , Wong Ivan , Whitney John , Quittmeyer Richard , Abrahamson Norman , Toro Gabriel , Youngs Robert , Coppersmith Kevin , Savy Jean , Sullivan Tim
Published: July 2003

Probabilistic seismic hazard analyses were conducted to estimate both ground motion and fault displacement hazards at the potential geologic repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada. The study is believed to be the largest and most comprehensive analyses ever conducted for ground-shaking hazard and is a first-of-a-kind assessment of probabilistic fault displacement hazard. The major emphasis of the study was on the quantification of epistemic uncertainty. Six teams of three experts performed seismic source and fault displacement evaluations, and seven individual experts provided ground motion evaluations. State-of-the-practice expert elicitation processes involving structured workshops, consensus identification of parameters and issues to be evaluated, common sharing of data and information, and open exchanges about the basis for preliminary interpretations were implemented. Ground-shaking hazard was computed for a hypothetical rock outcrop at -300 m, the depth of the potential waste emplacement drifts, at the designated design annual exceedance probabilities of 10-3 and 10-4. The fault displacement hazard was calculated at the design annual exceedance probabilities of 10-4 and 10-5.
Nonstructural Seismic Preparedness of Southern California Hospitals
Authors: Whitney David J. , Dickerson Andra , Lindell Michael K.
Published: July 2003

This study was conducted to assess the level of adoption of nonstructural seismic hazard adjustments by hospitals in Southern California, and to identify the factors that lead to adoption of these adjustments. Results provide evidence that hospitals in Southern California have partially implemented a variety of earthquake preparedness and mitigation activities. However, many adjustments specific only to earthquake hazard were not commonly implemented, and this is cause for concern. Successful implementation of nonstructural measures is most likely to occur in large hospitals having government or not-for-profit ownership, high levels of perceived support for seismic risk reduction from upper administrators, and frequent interaction of the hospital disaster coordinator with those in similar roles at other organizations.
Energy Balance Equation for Estimating Overturning Potential of an Unanchored Rocking Body Subjected to Earthquake Excitation
Authors: Aydin Kamil , Tung C. C.
Published: July 2003

In this paper, the validity of the energy balance equation is verified by statistical analysis. An ensemble of two hundred artificial earthquakes are generated and used as input to a structure on whose floors unanchored bodies are placed. The equation of motion governing the rocking motion of an unanchored body is solved and the probabilities of overturning are obtained. This information is used to show that the energy balance equation proposed by Housner is indeed valid. A few examples are given to demonstrate the use of the energy balance equation.
Energy Dissipation in Soil-Structure Interaction
Authors: Crouse C. B. , McGuire Jeff
Published: July 2003

Energy dissipation as a means of reducing the seismic response of structures has become a popular topic among researchers and structural engineers who have developed and implemented devices, such as friction dampers, fluid dampers, and isolators, in the design or retrofit of structures. However, a natural source of energy dissipation is the interaction between a structure, its foundation, and the supporting soil medium. To account for this frequency-dependent energy dissipation in dynamic analysis based on modal superposition, relatively simple and practical systems-identification methods are presented to estimate the composite modal damping ratios for the significant modes of vibration. SSI experiments and analysis of simple theoretical models using this method have yielded relatively large modal damping ratios in certain situations for structures such as short to mid-rise buildings, short-span bridges, flat bottom fuel storage tanks, offshore concrete gravity platforms, nuclear power plant containments, and nuclear waste processing plants.
Assembly-Based Vulnerability of Buildings and Its Use in Performance Evaluation
Authors: Porter Keith A. , Kiremidjian Anne S. , LeGrue Jeremiah S.
Published: July 2003

Assembly-based vulnerability (ABV) is a framework for evaluating the seismic vulnerability and performance of buildings on a building-specific basis. It utilizes the damage to individual building components and accounts for the building's seismic setting, structural and nonstructural design and use. A simulation approach to implementing ABV first applies a ground motion time history to a structural model to determine structural response. The response is applied to assembly fragility functions to simulate damage to each structural and nonstructural element in the building, and to its contents. Probabilistic construction cost estimation and scheduling are used to estimate repair cost and loss-of-use duration as random variables. It also provides a framework for accumulating post-earthquake damage observations in a statistically systematic and consistent manner. The framework and simulation approach are novel in that they are fully probabilistic, address damage at a highly detailed and building-specific level, and do not rely extensively on expert opinion. ABV is illustrated using an example pre-Northridge welded-steel-moment-frame office building.
Uniform Hazard Ground Motions for Mid-America Cities
Authors: Wen Y. K. , Wu C. L.
Published: July 2003

For performance evaluation of buildings and structures, synthetic uniform hazard (10% and 2% in 50 years) ground motions are generated for Memphis, Tennessee, St. Louis, Missouri, and Carbondale, Illinois. The method of simulation is based on the latest regional seismic information and stochastic ground motion models. Both point-source model and finite-fault model are used and the effects of soil profile are considered. The emphasis is on treatment of uncertainty and efficiency in application to evaluation of structural performance in both the linear and nonlinear range. The results show that the uniform hazard response spectra calculated from the simulated motions are comparable to those corresponding to USGS hazard maps. The suites of ten ground motions selected to match the uniform hazard response spectra represent events of different magnitudes, distances, and attenuation. The median value of the structural response to the selected ground motions matches closely the uniform hazard linear and nonlinear response spectra based on nine thousand ground motions and has a coefficient of variation of less than 10%. The suites of uniform hazard ground motions therefore can be used in probabilistic performance evaluation with good accuracy and efficiency.
Probabilistic Seismic Hazard Assessment of Sudan and Its Vicinity
Authors: Abdalla Jamal A. , Mohamedzein Yahia E-A. , Wahab A. Abdel
Published: July 2003

This paper presents seismic hazard assessment and seismic zoning of Sudan and its vicinity based on probabilistic approach. The area studied lies between 22° E- 45° E and 0° - 24° N. Tectonics of Sudan and its vicinity is first reviewed. An updated NOAA catalogue, containing both historical and instrumental events and covering the period from 700 A.D. to 1993 is then used. Seismic source regions are modeled and relationships between earthquake magnitude and earthquake frequency are established. A modified attenuation relation is used. Seismic hazard assessment is then carried out for 60 km interval grid points. Seismic hazard maps of the studied area based on peak ground acceleration (PGA) for 10% probability of exceedance for time-spans of 50, 100, 200 and 250 years are presented. The results showed that the PGA ranges from 0.02g for low seismic activity regions to around 0.62g for high seismic activity regions. A seismic zone map is also shown for 475 years return period.
Performance Evaluation of Passive Damping Systems for the Seismic Retrofit of Steel Moment-Resisting Frames Subjected to Near-Field Ground Motions
Authors: Filiatrault André , Tremblay Robert , Wanitkorkul Assawin
Published: July 2003

Passive friction and viscous damping systems for retrofitting steel moment-resisting frames located along the west coast of the United States are considered. First, preliminary design procedures are presented for friction as well as linear and nonlinear viscous damping systems. Thereafter, nonlinear dynamic analyses are performed on a six-story moment-resisting frame designed according to seismic provisions for California prior to the 1994 Northridge earthquake. A flexural strength degradation model is considered to account for the brittle behavior of pre-Northridge welded beam-to-column connections. The structure was subjected to three different earthquake ensembles including near-field records developed for major crustal earthquakes in California. The results of a parametric study indicate that, although both friction and viscous damping systems reduce significantly the response of the structure, they are unable by themselves to prevent fracture of welded beam-to-column joints. Connection retrofit measures of the types elaborated after the Northridge earthquake would still be required.
Reinforced Concrete Wide-Beam Construction vs. Conventional Construction: Resistance to Lateral Earthquake Loads
Authors: LaFave James M. , Wight James K.
Published: July 2003

Experiments and analyses were conducted to address concerns about performance of reinforced concrete connections with shallow, wide beams subjected to lateral earthquake loading and to compare behavior of wide beam connections to that of conventional connections. Two wide beam-column-slab connections and one conventional beam-column-slab connection were subjected to cycles of reversing lateral displacements up to 5% drift. The conventional beam and wide beam connections exhibited similar overall load-displacement behavior, with similar beam plastic hinge development. The wide beam connections dissipated almost as much energy as the conventional beam connection and had greater slab participation and less joint and beam shear cracking than the conventional beam connection. Experimentally determined wide beam connection stiffness was closer to the conventional beam connection stiffness than had been predicted. Refined models were developed, with features such as rigid end offsets for wide beam connections, to better represent observed behavior. Nonlinear models were also developed that accurately captured differences in energy dissipation as well as stiffness.
In-Situ Verification of Rehabilitation and Repair of Reinforced Concrete Bridge Bents under Simulated Seismic Loads
Authors: Pantelides Chris P. , Gergely Janos , Reaveley Lawrence D.
Published: July 2003

Three in-situ tests were performed on two bents of a reinforced concrete (RC) bridge under quasi-static cyclic loads. The bridge was built in 1963 and did not possess the necessary reinforcement details for ductile performance. The tests included an as-built bent, a bent rehabilitated with carbon fiber reinforced polymer (FRP) composite jackets, and a damaged bent repaired with epoxy injection and carbon FRP composite jackets. Two new concepts of strengthening bridge bents with FRP composites were implemented in this study. The first involves shear strengthening and confinement of a beam cap-column joint through an FRP composite “ankle-wrap.” The second is an FRP composite “U-strap” to improve the anchorage of column longitudinal steel reinforcement extending into the joint. FRP composite jackets were also implemented in the columns and beam cap. An additional rehabilitation measure was that of anchorage of the piles to the pile cap using epoxied high strength steel bars. The performance of the bent in the as-built condition and that of the rehabilitated and repaired bents is described in terms of strength, stiffness, displacement ductility, and energy dissipation.
Herbicide Resistant Plants, Production of
Authors: Songstad D.D.
Published: July 2003

Introduction

Resistance to Imidazolinone, Sulfonyl Urea, and Related Herbicides

Resistance to Glutamine Synthetase Inhibitor Herbicides

Resistance to Acetyl Coenzyme A Carboxylase Inhibiting Herbicides

Resistance to Photosystem II Inhibiting Herbicides

Resistance to 2,4‐D and Related Herbicides

Glyphosate‐Resistant Plants

Utilization of Herbicide Tolerance

Acknowledgments

Bibliography
Monocot Cell Culture
Authors: Brettell Richard
Published: July 2003

Introduction

Initiation of Callus Cultures and Regeneration of Plants

Protoplast Culture

Anther and Microspore Culture

Micropropagation

Embryo Culture

Concluding Remarks

Bibliography
Carbon Nanotube Composite Deposits with High Hardness and High Wear Resistance
Authors: Chen X. , Zhang G. , Chen C. , Zhou L. , Li S. , Li X.
Published: July 2003

A metal–carbon nanotube (CNT) composite has been synthesized by the authors simply by dispersing CNT's in a suitable electrolyte solution and depositing the metal in an electroless manner. The thus‐obtained CNT/Ni‐P coatings exhibit superior mechanical properties such as high hardness and excellent wear resistance. The Figure shows the intact morphology of worn CNT/Ni‐P (left) vs. the bruised surface of conventional Ni‐P.
High‐Temperature Deformation Behavior of the Bond–Coat Alloy PWA 1370
Authors: Schwarzer J. , Vöhringer O.
Published: July 2003

The high‐temperature deformation behavior of the NiCoCrAlY alloy PWA 1370, which is applied as a bond‐coat material in thermal barrier‐coating systems, was investigated at temperatures up to 950 °C by means of constant extension rate tests (CERTs) and was described with a modified Norton creep law. Furthermore, experiments to determine Young's modulus and compressive yield strength at high temperature are reported.