bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct and Indirect Economic Losses from Earthquake Damage
Authors: Brookshire David S. , Chang Stephanie E. , Cochrane Hal , Olson Robert A. , Rose Adam , Steenson Jerry
Published: July 2003

Earthquakes generate a variety of economic impacts. To obtain a consistent measure, the actual damage state must be linked to the dollar losses of the capital stock, and then translated into direct business interruption losses and the ensuing ripple effects that occur throughout the economy. The Earthquake Loss Estimation Methodology (HAZUS) facilitates a consistent set of loss estimations. The direct loss module of HAZUS calculates loss estimates for repair and replacement of building stock (structural and nonstructural), building contents and inventory, and business interruption losses. The direct losses information provides the inputs to the indirect loss module. The indirect loss module estimates the impacts by economic sectors over time and accounts for both earthquake-induced supply shortages and demand reductions. The results of a case study are presented that focus on the economic impacts of various scenario earthquakes that might occur in the Boston metropolitan area.
Earthquake Loss Estimation for Europe's Historic Town Centres
Authors: D'Ayala Dina , Spence Robin , Oliveira Carlos , Pomonis Antonios
Published: July 2003

To support decision-making on upgrading strategies of historic city centres, loss estimation techniques are needed, suitable for application to masonry buildings. This paper describes the development and application of such techniques to a case study in the Alfama District of Lisbon. The project involved a survey of 200 buildings to investigate structural features and condition, mapped using a GIS system, followed by analysis of key collapse mechanisms to define static collapse loads under horizontal forces for each building. The results, obtained in terms of earthquake ground motions likely to produce equivalent damage, led to the development of vulnerability functions for the case study, verified by comparison with functions derived from statistical analysis of world-wide damage reports and with damage reports of the 1755 Lisbon earthquake. The method is used to predict the reduction in losses achieved by the introduction of low-cost unobtrusive strengthening techniques, such as tie-rods connecting facade walls to floors and cross-walls. Cost benefit analysis, considering only structural costs, indicates that the return on the investment would be considerable.
Real-Time Loss Estimation as an Emergency Response Decision Support System: The Early Post-Earthquake Damage Assessment Tool (EPEDAT)
Authors: Eguchi Ronald T. , Goltz James D. , Seligson Hope A. , Flores Paul J. , Blais Neil C. , Heaton Thomas H. , Bortugno Edward
Published: July 2003

At the time of the Northridge earthquake, a number of new technologies, including real-time availability of earthquake source data, improved loss estimation techniques, Geographic Information Systems and various satellite-based monitoring systems, were either available or under consideration as emergency management resources. The potential benefits from these technologies for earthquake hazard mitigation, response and recovery, however, were largely conceptual. One of the major lessons learned from the January 17, 1994 earthquake was that these technologies could confer significant advantages in understanding and managing a major disaster, and that their integration would contribute a significant additional increment of utility. In the two and half years since the Northridge earthquake, important strides have been taken toward the integration of relatively discrete technologies in a system which provides real-time estimates of regional damage, losses and population impacts. This paper will describe the development, operation and application of the first real-time loss estimation system to be utilized by an emergency services organization.
The Treatment of Earthquake Portfolio Uncertainty: A Focus on Issues of Asset Distribution
Authors: Woo Gordon
Published: July 2003

In estimating the earthquake loss at a given site, procedures have been developed by earthquake engineers for treating the uncertainty arising from lack of knowledge and intrinsic stochastic variability in the local seismic hazard, and in the vulnerability of the property occupying the site. However, in estimating the earthquake loss, not just for a single site, but for a town or county, or for a group of regionally dispersed properties, or for a collection of mobile or portable assets, the treatment of portfolio uncertainty presents an additional statistical challenge to current methodology and practice. Spatial statistical methods are here applied to address portfolio uncertainty; an issue which is particularly important for insurance catastrophe management.
Equivalent Static Eccentricities in the Simplified Methods of Seismic Analysis of Buildings
Authors: Anastassiadis K. , Athanatopoulou A. , Makarios T.
Published: July 2003

The equivalent static eccentricities of seismic forces are usually defined by codes with simple expressions of the static eccentricity. This paper presents certain formulae for the exact calculation of these eccentricities on the basis of the dynamic response of a simplified model. From the parametric analysis of such formulae the determinative role of the torsional and lateral stiffness of the system becomes obvious for the correct evaluation of the equivalent static eccentricities. Finally, a proposal is made for the improvement of the static torsional provisions of the current codes.
Plans, Code Enforcement, and Damage Reduction: Evidence from the Northridge Earthquake
Authors: Burby Raymond J. , French Steven P. , Nelson Arthur C.
Published: July 2003

The State of California requires local governments to pay attention to seismic safety in formulating general plans for urban development and in permitting and inspecting new construction and remodeled existing structures. The Northridge earthquake provided an opportunity to determine whether these provisions, which have been mandatory for more than two decades, actually result in lower property damages. Using data on the number of structures damaged in the Northridge event, we show that, for suburban jurisdictions, damages were lower when local governments formulated broader goals for seismic safety, developed policies to make the public more aware of seismic risks, and expended more resources on enforcing the seismic provisions of building codes. Thus, seismic safety mandates on local governments can lead to lower property damages, and these benefits are enhanced when local governments expend more effort on their implementation.
Site Effects and Microzonation in Acapulco
Authors: Chávez-García Francisco J. , Cuenca Julio
Published: July 2003

The region around Acapulco, on the Pacific coast of Mexico, is subjected to large seismic risk. This paper presents a contribution to improve microzonation of this region. We investigated site effects using three basic sources of data: strong-motion records from all of the instruments that have operated within the area; weak-motion records obtained from the installation and operation of a temporal, digital, seismograph network; and measurements of microtremors at 35 sites. We compared and evaluated different techniques of data analysis. We show that very coherent results are obtained from different kinds of measurement, and that microtremor records are very useful to interpolate sparse earthquake data. We propose two maps that reflect the fundamental characteristics of site effects in the area: dominant period and maximum relative amplification. These maps may be used to improve current microzonation of Acapulco.
Stiffness Design for Specified Nonexceedance Probability of Seismic Response
Authors: Nakamura Yutaka , Nakamura Tsuneyoshi
Published: July 2003

A direct procedure is presented for generating a response spectrum for an arbitrary nonexceedance probability from a prescribed design mean response spectrum. An amplification factor is derived to estimate the maximum response values of an MDOF system for a nonexceedance probability from the mean maximum ones. An efficient stiffness design method for a shear building is developed with the use of its fundamental frequency and translational eigenvector as parameters for adjusting the nonexceedance probability of the seismic drifts to the specified value. The validity and accuracy of the proposed method are demonstrated by a Monte Carlo simulation together with time-history analyses.
Data Analysis of the Euroseistest Strong Motion Array in Volvi (Greece): Standard and Horizontal-to-Vertical Spectral Ratio Techniques
Authors: Raptakis D. , Theodulidis N. , Pitilakis K.
Published: July 2003

In this study, the standard spectral ratio and the horizontal-to-vertical spectral ratio techniques are applied in order to study their effectiveness in investigating and quantifying the influence of geological conditions on strong ground motion. For this purpose, an accelerogram data set recorded at the Euroseistest array in the Mygdonia graben (lake Volvi area) near Thessaloniki, Greece, during the period April 1994 to June 1996 is used. Both experimental techniques show similar spectral ratio shapes with comparable fundamental resonant frequencies, which are well correlated with the well known geotechnical-geological conditions. Namely, the resonant frequency at the center of the valley is shifted to lower values, less than 1 Hz, while at the edge it is shifted to higher values, greater than 2 Hz. The horizontal-to-vertical spectral ratio technique is an effective method to estimate some basic characteristics of local site effects using a single accelerograph station. It reveals the fundamental resonant frequency of alluvial deposits by using only a single strong motion station, while the absolute level of the horizontal-to-vertical spectral ratio method tends to underestimate the amplification level compared to the standard spectral ratio technique.
Direct Economic Losses in the Northridge Earthquake: A Three-Year Post-Event Perspective
Authors: Eguchi Ronald T. , Goltz James D. , Taylor Craig E. , Chang Stephanie E. , Flores Paul J. , Johnson Laurie A. , Seligson Hope A. , Blais Neil C.
Published: July 2003

The Northridge earthquake will long be remembered for the unprecedented losses incurred as a result of a moderate-size event in a suburban area of Los Angeles. Current documented costs indicate that this event is the costliest disaster in U.S. history. Although it is difficult to estimate the full cost of this event, it is quite possible that total losses, excluding indirect effects, could reach as much as $40 billion. This would make the Northridge earthquake less severe than the Kobe event, which occurred exactly one year after the Northridge earthquake, but adds a bit of realism that a Kobe-type disaster is possible in the U.S. This paper attempts to put into perspective the direct capital losses associated with the Northridge earthquake. In doing so, we introduce the concept of hidden and/or undocumented costs that could double current estimates. In addition, we present the notion that a final estimate of loss may be impossible to achieve, although costs do begin to level off two years after the earthquake. Finally, we attempt to reconcile apparent differences between loss totals for two databases tracking similar information.
Nonlinear Analyses of an Instrumented Structure Damaged in the 1994 Northridge Earthquake
Authors: Li Y. Roger , Jirsa James O.
Published: July 2003

The extensive damage and economic losses that occurred during the 1994 Northridge and other recent moderate earthquakes have stimulated structural engineers to consider how to protect economic investment besides meeting life safety requirements of buildings. The equivalent lateral force procedure for seismic design is based on implicit consideration of inelastic response of structures in earthquakes. Experience with past earthquakes has indicated that this procedure is inadequate in controlling damage in buildings. The objective of this study is to demonstrate the capability of nonlinear dynamic analyses to predict performance of reinforced concrete structures subjected to earthquake ground motions. An instrumented building damaged during the 1994 Northridge earthquake was analyzed using DRAIN-2D, and the results were compared with recorded response data. Both nonlinear dynamic time history and nonlinear static push-over analyses were performed, and correlations between these two nonlinear analysis methods were studied. A simplified shear failure model was proposed in the study.
Earthquake Impacts and Hazard Adjustment by Acutely Hazardous Materials Facilities following the Northridge Earthquake
Authors: Lindell Michael K. , Perry Ronald W.
Published: July 2003

Hazardous materials pose a problem of great significance for earthquake hazard reduction because severe earthquakes can simultaneously fail independent systems for on-site release mitigation and off-site emergency response. Unfortunately, the potential for major earthquake-initiated hazmat releases (EIHRs) has received little attention from earthquake researchers and planners. This study assessed the extent of on-site and off-site damage to fixed-site hazmat facilities and the hazard adjustments (i.e., hazard assessment, hazard mitigation, and emergency preparedness actions) that these facilities implemented before and after the Northridge earthquake. Data on the occurrence of chemical containment and infrastructure systems impacts confirms that hazmat facility infrastructure is vulnerable to seismic impacts. Hazard adjustments were undertaken after the earthquake, but were unrelated to the level of earthquake impact. These results suggest that comprehensive EIHR loss estimation studies should be conducted for seismic zones throughout the country, especially for clusters of hazmat facilities subject to the threat of damaging earthquakes.
A Stochastic Approach in Estimating the Pseudo-Relative Spectral Velocity
Authors: Liu Li Jun , Pezeshk Shahram
Published: July 2003

In the prediction of ground motion from seismological model by random vibration theory, the basic assumption as that the ground motion process is a bandlimited Gaussian white noise (BGWN). For pseudo-response spectral values, the estimation is based on the response of a single-degree-of-freedom (SDOF) system due to the input of BGWN. The function of an SDOF is a narrowband filter. Therefore, the response of an SDOF is a narrowband process that no longer satisfies the assumption of bandlimited random process. The property of a narrowband process is significantly different from that of a bandlimited process and should be incorporated into the estimation of pseudo-spectral values. A stochastic methodology is proposed to estimate the spectral values on the basis of narrowband Gaussian stationary process. A key feature of the method is the use of envelope crossings in lieu of press crossings of the ground motion amplitude level. This substitution makes the estimation of spectral values more accurate. Comparing our results with those of previous research studies, we will illustrate that our proposed approach is in a good agreement with that of the simulation of time domain.
Seismic Behavior and Deterministic Design Procedures for Steel V-Braced Frames
Authors: Remennikov Alexander M. , Walpole Warren R.
Published: July 2003

This paper presents an approach for designing low-rise steel framed buildings with inverted-V-bracing for severe earthquakes. A deterministic design philosophy is used with respect to earthquake-resisting ductile steel braced frames. Seismic behavior of steel frames with inverted-V-bracing is discussed. A series of dynamic analyses was performed on a two-story inverted-V-Braced frame, subjected to near-field ground motions. Ground shaking of this type may be expected in New Zealand, within 10 to 15 km from the Wellington fault, or in the United States in Seismic Zone 4. Post-elastic behavior of braces, beams, and columns is discussed. From the results of dynamic analyses, the interrelations between the seismic forces in frame members are identified. The expressions for the maximum expected seismic design actions in those elements are derived, following the capacity design method. It is believed that this approach will result in stronger and more ductile frames that are capable of resisting the near-field ground motions.
Nonlinear Seismic Soil-Pile Structure Interaction
Authors: Wang Shaomin , Kutter Bruce L. , Chacko M. Jacob , Wilson Daniel W. , Boulanger Ross W. , Abghari Abbas
Published: July 2003

Analytical design tools for evaluation of soil-pile-structure interaction during seismic events are evaluated and modified. Several implementations of the “Beam on Nonlinear Winkler Foundation” (BNWF) method were used to predict results of centrifuge model tests of single piles in a soft clay soil profile. This paper shows that calculations from these computer codes can be sensitive to the details of the arrangement of nonlinear springs and linear viscous dashpots. Placing the linear viscous dashpots (representing radiation damping in the far field) in series with the hysteretic component of the p-y elements (representing the nonlinear soil-pile response in the near field) is shown to be technically preferable to a parallel arrangement of the viscous and hysteretic damping components. Preliminary centrifuge data is reasonably modeled by the numerical calculations using this implementation of damping, but additional field or physical model data are needed to fully evaluate the reliability of BNWF procedures.
How Reliable Are Global Computer Models? Correlation with Large-Scale Tests
Authors: Negro Paolo , Colombo Antonella
Published: July 2003

The pseudodynamic tests recently performed at the European Laboratory for Structural Assessment provide an unprecedented wealth of experimental results against which computer models can be assessed. The paper focuses on the simplest nonlinear models for R/C structures. These are the most widely used, therefore calibration guidelines are badly needed. Moreover, since their use does not require particular mastery of numerical techniques, they may be used by professional engineers as an alternative to the linear models that have almost exclusively adopted so far. In this paper the experimental results for a number of R/C structures (a full-scale four-story building, the same building with masonry infills, and four large-scale four-span regular and irregular bridges) are compared with the results that can be obtained by means of nonlinear analyses with simple global models. They proved to be simple and reliable. Some derived calibration guidelines for these models are presented, which may be used as a source of reference for studying similar ductile structures.
Earthquakes, Records, and Nonlinear Responses
Authors: Shome Nilesh , Cornell C. Allin , Bazzurro Paolo , Carballo J. Eduardo
Published: July 2003

The estimation of MDOF nonlinear structural response given an earth-quake of magnitude M at distance R is studied with respect to issues such as the benefits and harms of (1) first scaling the records, (2) selecting records from the “wrong” magnitude, (3) alternative choices for how to scale the records, and (4) scaling records to a significantly higher or lower intensity, etc. We find that properly chosen scaling can reduce the necessity of the number of nonlinear analyses by a factor of about four, and that proper scaling does not introduce any bias. Several global and local nonlinear damage measures are considered. A five-DOF model of a steel structure is used; other cases are under study. The paper finishes with a demonstration of the use of such results in the estimation of the annual probability of exceeding a specified interstory ductility (drift) or other damage measures.
Seismic Performance of Moment-Resisting Steel Frame Structures Designed for Different Levels of Seismic Hazard
Authors: Biddah Aiman , Heidebrecht Arthur C.
Published: July 2003

A large number of low and medium-rise buildings have moment-resisting steel frames as the primary lateral load resisting system. This type of structural system has been considered to be one of the most effective means for resisting strong seismic ground motions. This paper presents the results of an investigation into the performance which can be expected when code designed ductile moment-resisting steel frame buildings having ductile connections, designed for different seismic hazard levels, are subjected to excitation by strong seismic ground motions. Design variations at different seismic hazard levels include three design philosophies, namely strong-column weak-beam, weak-column strong-beam and strong-column weak panel zone. The analytical model used in the study takes into account both connection flexibility and panel zone shear deformation. Results show that the performance arising from a specific design philosophy may be acceptable in one seismic hazard region, while being unacceptable in a region having a different seismic hazard level.
Policy Design for Earthquake Hazard Mitigation: Lessons from Energy Conservation, Radon Reduction, and Termite Control
Authors: May Peter J. , Burby Raymond J. , Kunreuther Howard
Published: July 2003

The failure of homeowners to invest in mitigation measures for reducing potential losses from earthquakes presents a major obstacle to stemming economic losses. The design of earthquake risk reduction policies requires an understanding of the appropriate combination of institutional and individual incentives for inducing investment in mitigation. We address the challenges of inducing protective actions by considering the experiences with energy conservation, radon reduction, and termite control. We examine the institutional design of relevant policies and programs, the role of various intermediaries, and the involvement of third parties in creating markets for services. From this, we draw lessons about the leveraging of governmental resources, fostering of markets for services, and carrying out of programs for outreach and education.
EERI Distinguished Lecture 1997 Professional Commitments to Earthquake Engineering
Authors: Paulay Thomas
Published: July 2003

Philosophical concepts, biased toward structural design in seismic regions, are offered. Certain misconceptions in the aims, planning and execution of structural design are sketched. Apparent diverging professional interests, motivating on the one hand young academics dedicated to pursuing challenges in research, and on the other hand those of experienced practitioners, are contrasted. A plea is made to use in seismic design rationality and simplicity in application. The primary aim in the art of structural design should be to impart to the system specific properties that will make the seismic response of our buildings extremely tolerant with respect to earthquake-induced demands, which presently we can predict only with considerable crudeness. A postulated rational and deterministic, yet simple, design strategy should be implemented with equal dedication to high-quality construction. This part of the creative effort is likely to result in properties of the finished product, our buildings, which earthquakes will also recognize and respect. An appeal is made to all those committed to earthquake engineering to engage in active and generous support of technology transfer in an attempt to alleviate the overwhelming and immediate needs of societies in developing countries.
Toppling Fragility of Unrestrained Equipment
Authors: Zhu Z. Y. , Soong T. T.
Published: July 2003

Block-type equipment without restraining devices and under earthquake loads can effectively be modeled as freestanding rigid blocks resting on supporting bases subjected to base excitations. Once the peak values of base excitation levels, the aspect ratio of the bock, and the static friction coefficient between the block and the supporting base are known, the motion type of the block that will be initiated under base excitation can be determined. One of the possible motion types is rocking. When rocking is initiated, the block may topple and suffer severe damage and permanent loss of function. The emphasis of this study is placed on quantifying the possibility of toppling of a rigid block during rocking motion given its geometry and design earthquake environment. Using floor response spectra to characterize excitation inputs, results are given in the form of toppling fragility curves, i.e., probability of toppling as a function of peak ground accelerations. Parametric sensitivity studies are also carried out to show the effects of several key parameters on the fragility results.
GPS Monitoring of Dynamic Behavior of Long-Period Structures
Authors: Çelebi Mehmet , Prescott Will , Stein Ross , Hudnut Ken , Behr Jeff , Wilson Steve
Published: July 2003

Global Positioning System (GPS) technology with high sampling rates (∼10 sps) allows scientifically justified and economically feasible dynamic measurements of relative displacements of long-period structures—otherwise difficult to measure directly by other means, such as the most commonly used accelerometers that require post-processing including double integration. We describe an experiment whereby the displacement responses of a simulated tall building are measured clearly and accurately in real-time. Such measurements can be used to assess average drift ratios and changes in dynamic characteristics and therefore can be used by engineers and building owners or managers to assess the building performance during extreme motions caused by earthquakes and strong winds, by establishing threshold displacements or drift ratios and identifying changing dynamic characteristics. Such information can then be used to secure public safety and/or take steps to improve the performance of the building.
FRC-Steel Joist Composite Frames for Seismic Resistance
Authors: Khuntia Madhusudan , Goel Subhash C.
Published: July 2003

The research reported in this paper is concerned with development of fiber-reinforced concrete-encased open web steel joist composite frames for seismic resistance. This new and innovative system completely eliminates the need for any shear connectors between steel joists and surrounding concrete as well as that for conventional longitudinal and transverse reinforcement, all of which are quite labor intensive. In the initial phase of the study tests were carried out on half-scale beam specimens subjected to monotonic and reversed cyclic loading. The results showed that the presence of steel fibers as well as the open web steel significantly enhances the shear capacity of the system thus making it very suitable for seismic resistance. In the final phase, a half-scale, one-story, one-bay frame was designed by strong column-weak beam concept. The results showed ductile and stable hysteretic behavior. The study indicates that this type of composite framing system has excellent potential in seismic regions.
An Overall Evaluation of Irregular-Floor-Plan—Shaped Buildings Located in Seismic Areas
Authors: López Oscar A. , Raven Elizabeth
Published: July 2003

This paper aims to identify and analyze the advantages and disadvantages associated with building plan shape considering engineering and architectural needs and to quantify them in terms of the common language of costs and benefits. Parameters that measure the overall seismic response of a given plan shape were defined. Seismic behavior of the irregular shapes can be improved by means of special engineering efforts that provide enough in-plane slab stiffness and a distribution of lateral stiffness and strength so that torsion and distortion can be minimized. The proposed procedure of integral evaluation of buildings was applied to two specific examples, one regular and one irregular building, both with similar characteristics. The irregular building was seismically adequate by means of several dynamic analyses and a careful structural design so that it reached an acceptable level of seismic performance. For this example, the irregular building offers long-term benefits that exceed the initial investment required to improve its seismic behavior.
The Relationship of Foundation Deformation to Surface and Near-Surface Faulting Resulting from the 1992 Landers Earthquake
Authors: Murbach Diane , Rockwell Thomas K. , Bray Jonathan D.
Published: July 2003

Surface rupture associated with the 1992 Landers earthquake (Mw 7.3) damaged several structures in the southwest Mojave desert. Six trenches were excavated through and adjacent to three structures that were damaged by directfault displacement. Trenching insights assisted in understanding foundation failures. This investigation confirms the surface shear zones, documents subsurface fault rupture geometry, and describes the effects on those structures. The surface pattern of rupture consisted of left-stepping, right-lateral shears with local vertical components within broader zones of shearing. The trenches generally exposed poorly stratified granular materials in which faults that were previously mapped on the surface were difficult to recognize. The age and material properties of the alluvium influenced the pattern of deformation. A strong correlation was found between the geometry of faulting and the pattern of residential concrete slab deformation. These observations suggest that an adequately reinforced concrete slab with poor coupling to the ground may minimize damage due to direct surface rupturing.
Correlates of Damage to Residences following the Northridge Earthquake, as Reported in a Population-Based Survey of Los Angeles County Residents
Authors: Shoaf Kimberley I. , Bourque Linda B.
Published: July 2003

Damage to residential structures as a result of earthquakes can be viewed from the perspective of geologic and engineering sciences and from the perspective of the social sciences. Utilizing data collected from a population-based survey, this paper concludes that the distribution of damage, the types of damage, the dollar amount of damage, whether or not homes were inspected and the results of those inspections following the Northridge earthquake correlate with measures of intensity of the earthquake, as well as with characteristics of the building and with characteristics of the household. Interestingly, pga is generally a better predictor of damage than MMI, newer homes suffered more damage than older ones, and higher income households were more affected than lower income households.
The Behavior of Bearings Used for Seismic Isolation under Shear and Axial Load
Authors: Mori Atsushi , Moss Peter J. , Cooke Nigel , Carr Athol J.
Published: July 2003

The investigation described in this paper looked at both laminated elastomeric bearings and lead-rubber bearings in order to obtain a better understanding of the real bearing behavior under the combined action of shear and axial loads when used in a seismic-isolation system. In particular, the investigation focused on the distributions of vertical pressure on the bearing faces and the degree of lift-off of the edges of the bearings as the shearing displacement and the angle of rotation increased.
The Behavior of Bearings Used for Seismic Isolation under Rotation and Axial Load
Authors: Mori Atsushi , Moss Peter J. , Cooke Nigel , Carr Athol J.
Published: July 2003

The investigation described in this paper looked at both laminated elastomeric bearings and lead-rubber bearings in order to obtain a better understanding of the real bearing behavior under the combined action of rotation and axial loads when used in a seismic-isolation system. In particular, the investigation focused on the distributions of vertical pressure on the bearing faces and the degree of lift-off of the edges of the bearings as the angle of rotation increased.
Seismic Analysis of Older Reinforced Concrete Columns
Authors: Pincheira JoséA. , Dotiwala Faridun S. , D'Souza Jonathan T.
Published: July 2003

A nonlinear model and an analytical procedure for calculating the cyclic response of nonductile reinforced concrete columns are presented. The main characteristics of the model include the ability to represent flexure or shear failure under monotonically increasing or reversed cyclic loading. Stiffness degradation with cyclic loading can also be represented. The model was implemented in a multipurpose analysis program and was used to calculate the response of selected columns representative of older construction. A comparison of the calculated response with experimental results shows that the strength, failure mode and general characteristics of the measured cyclic response can be well represented by the model.
Variability of Damage Ratios for Property in Earthquakes
Authors: Rhoades David A. , Dowrick David J.
Published: July 2003

In studies of damage to classes of property in earthquakes, the damage ratio for a class as a whole, denoted D¯r, can differ appreciably from the mean damage ratio Drm of properties in the class. Two factors that influence the propensity of D¯r and Drm to differ are the skewness of the distribution of property values and any systematic relation that may exist between property value and damage ratio. The existence of such relations is demonstrated using data from two major New Zealand earthquakes, at Napier ( Mw7.8, 1931) and Edgecumbe ( Mw6.5, 1987). A common trend is that the probability of a property being damaged increases with increasing value. The damage ratio may tend to increase or decrease with property value, depending on the type of property. The observed relations can be partially explained on physical grounds, and have implications for earthquake resistant design and earthquake insurance.
Optimal Design of ADAS Damped MDOF Structures
Authors: Ribakov Yuri , Gluck Jacob
Published: July 2003

Incorporated at various levels of a structural frame, ADAS devices may be used to improve the response of the structure during earthquakes. A design method of a passive control system for multistory structures using optimal Adding Damping And Stiffness (ADAS) dampers is presented. Optimal Control Theory (OCT) is commonly used to obtain the levels of viscous damping at each story. The optimization leads to different levels of damping at each story. Therefore, a solution with viscous dampers is inconvenient and can be expensive. The proposed method enables the use of relatively less expensive optimal ADAS devices dissipating energy which is equivalent to that of viscous dampers. The method is examined in a numerical analysis of a seven-story shear framed structure. Significant improvement was obtained in the behavior of the ADAS damped structure compared to the uncontrolled one.
International Seismic Zone Tabulation Proposed by the 1997 UBC Code: Observations for Mexico
Authors: Tena-Colunga Arturo
Published: July 2003

The Uniform Building Code (UBC) is perhaps one of the most advanced seismic codes worldwide. The 1997 version of the Uniform Building Code (UBC-97) has important modifications with respect to previous versions, among other changes, the introduction of structural overstrength, redundancy and reliability factors for the design of structural elements. In addition, the UBC-97 code revises seismic zoning for areas outside the United States under Division III, Section 1653. In fact, practically the entire world is zoned by the UBC-97 under this section, and many practicing engineers worldwide may feel confident to use the UBC code for the design of civil structures in countries other than the United States, particularly because it is written in this section that “Note: This division has been revised in its entirety”. This paper discusses whether or not Section 1653 of the UBC-97 code has any justification for Mexico, by comparing the UBC design criteria with the criteria established by ruling Mexican codes. According to Mexican authorities, only the referenced Mexican building codes should be used for the design of civil structures in Mexico, so the UBC-97 cannot be used for the seismic design of civil structures in Mexico legally.
Extant Panel Zone Design Procedures for Steel Frames Are Questioned
Authors: Englekirk Robert E.
Published: July 2003

Current design procedures for steel special moment frames (SMF) promote panel zone yielding. Reliance on this yielding is likely to result in poor frame performance in spite of the fact that it has been demonstrated that panel zones can yield. Eight previously tested subassemblies are analyzed for compliance with current code design procedures. The observed behavior of these subassemblies is discussed and contrasted to behavior objectives of steel SMF's. Revised design procedures are proposed.
Logic Tree Analysis of Secondary Nonstructural Systems with Independent Components
Authors: Roth Christopher
Published: July 2003

The seismic performance of a nonstructural secondary system depends on the performance of each component of the system, and on the way in which the components are connected. The performance of each component is commonly described using fragility curves. Logic trees may be used to describe the way in which the components are connected. The use of logic tree analysis for secondary systems is briefly reviewed, and the method extended to allow the determination of the sensitivity of the system failure probability to the failure probability of any component of the system. An approximate method is proposed to find confidence intervals for the failure probability of the system, given uncertainty in the failure probability of each component. The method was found to give good results.
Toward Performance-Based Seismic Design of Structures
Authors: Leelataviwat Sutat , Goel Subhash C. , Stojadinović Božidar
Published: July 2003

A new performance-based plastic design procedure for steel moment frames is presented in this paper. The role of plastic analysis in seismic design of structures is illustrated. The ultimate design base shear for plastic analysis is derived by using the input energy from the design pseudo-velocity spectrum, a pre-selected yield mechanism, and an ultimate target drift. The proposed design procedure eliminates the need for a drift check after the structure is designed for strength as is done in the current design practice. Also, there is no need for response modification factors since the load deformation characteristics of the structure, including ductility and post-yield behavior, are explicitly used in calculating the design forces. The results of nonlinear static and nonlinear dynamic analyses of an example steel moment frame designed by the proposed method are presented and discussed. The implications of the new design procedure for future generation of seismic design codes are also discussed.
A Model for Buildings' Vulnerability Assessment Using the Parameterless Scale of Seismic Intensity (PSI)
Authors: Orsini Giampiero
Published: July 2003

After the earthquake of 1980 in Irpinia the Italian Government promoted a damage survey, with the cooperation of researchers of the “Progetto Finalizzato Geodinamica, Consiglio Nazionale delle Ricerche PFG-CNR.” The data of the damage survey have been used in several studies during previous years, and in the present work they have been elaborated on with the aim of assessing a value of the seismic excitation in each administrative unit according to the Parameterless Scale of Seismic Intensity (PSI) (Spence et al., 1991). The PSI intensities are in good correlation with the values of the MSK scale: for each degree of the latter, the PSI intensity, a continuous variable, shows a spectrum of values. At the same time, a model for damage prediction has been identified, where the frequency of a damage degree in a territorial unit is a function of PSI. The proposed damage prediction model has been compared with the Damage Probability Matrix method and the range of variation of the losses evaluated in scenario analyses at the National Seismic Survey has been estimated.
TriNet “ShakeMaps”: Rapid Generation of Peak Ground Motion and Intensity Maps for Earthquakes in Southern California
Authors: Wald David J. , Quitoriano Vincent , Heaton Thomas H. , Kanamori Hiroo , Scrivner Craig W. , Worden C. Bruce
Published: July 2003

Rapid (3-5 minutes) generation of maps of instrumental ground-motion and shaking intensity is accomplished through advances in real-time seismographic data acquisition combined with newly developed relationships between recorded ground-motion parameters and expected shaking intensity values. Estimation of shaking over the entire regional extent of southern California is obtained by the spatial interpolation of the measured ground motions with geologically based frequency and amplitude-dependent site corrections. Production of the maps is automatic, triggered by any significant earthquake in southern California. Maps are now made available within several minutes of the earthquake for public and scientific consumption via the World Wide Web; they will be made available with dedicated communications for emergency response agencies and critical users.
Relationships between Peak Ground Acceleration, Peak Ground Velocity, and Modified Mercalli Intensity in California
Authors: Wald David J. , Quitoriano Vincent , Heaton Thomas H. , Kanamori Hiroo
Published: July 2003

We have developed regression relationships between Modified Mercalli Intensity ( Imm) and peak ground acceleration (PGA) and velocity (PGV) by comparing horizontal peak ground motions to observed intensities for eight significant California earthquakes. For the limited range of Modified Mercalli intensities ( Imm), we find that for peak acceleration with V ≤ Imm ≤ VIII, Imm = 3.66 log( PGA) − 1.66, and for peak velocity with V ≤ Imm ≤ IX, Imm = 3.47 log( PGV) + 2.35. From comparison with observed intensity maps, we find that a combined regression based on peak velocity for intensity > VII and on peak acceleration for intensity < VII is most suitable for reproducing observed Imm patterns, consistent with high intensities being related to damage (proportional to ground velocity) and with lower intensities determined by felt accounts (most sensitive to higher-frequency ground acceleration). These new Imm relationships are significantly different from the Trifunac and Brady (1975) correlations, which have been used extensively in loss estimation.
Surface Seismic Measurements of Near-Surface P- and S-Wave Seismic Velocities at Earthquake Recording Stations, Seattle, Washington
Authors: Williams Robert A. , Stephenson William J. , Frankel Arthur D. , Odum Jack K.
Published: July 2003

We measured P- and S-wave seismic velocities to about 40-m depth using seismic-refraction/reflection data on the ground surface at 13 sites in the Seattle, Washington, urban area, where portable digital seismographs recently recorded earthquakes. Sites with the lowest measured Vs correlate with highest ground motion amplification. These sites, such as at Harbor Island and in the Duwamish River industrial area (DRIA) south of the Kingdome, have an average Vs in the upper 30 m (V¯s30) of 150 to 170 m/s. These values of V¯s30 place these sites in soil profile type E (V¯s30 < 180 m/s). A “rock” site, located at Seward Park on Tertiary sedimentary deposits, has a V¯s30 of 433 m/s, which is soil type C (V¯s30: 360 to 760 m/s). The Seward Park site V¯s30 is about equal to, or up to 200 m/s slower than sites that were located on till or glacial outwash. High-amplitude P- and S-wave seismic reflections at several locations appear to correspond to strong resonances observed in earthquake spectra. An S-wave reflector at the Kingdome at about 17 to 22 m depth probably causes strong 2-Hz resonance that is observed in the earthquake data near the Kingdome.
Field Act Public Schools … a Need for Safety Reviews
Authors: Mujumdar Vilas , McGavin Gary
Published: July 2003

The Field Act has enabled a higher design and construction requirement for California's public schools since 1933. Much has been learned of earthquake design and construction since the enactment of the Field Act. The design profession has found, from experience in actual earthquakes, that some types of construction and structural systems have less than desirable responses to earthquakes. Children and staff in some of these facilities may be at risk. This paper urges that some older Field Act-approved structures should be reviewed for seismic safety. Systems such as nonductile reinforced concrete frames and tilt-up concrete construction are at a high level of concern. Other concerns include deterioration of older school facilities, inappropriate modifications, and nonstructural items in schools built before modern codes addressed the potential for nonstructural damage. This paper reviews these issues and calls for statewide examination of older Field Act-approved public schools in order to determine the extent of public schools that might be at some level of seismic risk.
On the Use of Elastic Input Energy for Seismic Hazard Analysis
Authors: Chapman Martin C.
Published: July 2003

The disaggregation of probabilistic seismic hazard calculations based on elastic input energy may prove useful for the identification of scenario events because input energy is a convenient single-parameter descriptor of motion duration and amplitude. To investigate this application, regression models are derived for the absolute input energy equivalent velocity, Vea, and the elastic pseudo-relative velocity response, PSV, in the frequency range 0.5 to 10 Hz. Disaggregation of a general seismic hazard model using Vea indicates that the modal magnitudes for the higher frequency oscillators tend to be larger, and vary less with oscillator frequency, than those derived using PSV. Larger magnitude earthquakes contribute more to seismic hazard if Vea is used. The dependence of Vea and PSV upon site classification is virtually identical, and Vea can be predicted with slightly less uncertainty as a function of magnitude, distance and site classification.
Retrofit for Control and Repairability of Damage
Authors: Dutta Anindya , Mander John B. , Kokorina Tatiana
Published: July 2003

Collapse or severe damage of a large number of bridges in recent earthquakes in California and Japan has emphasized the need to develop a suitable retrofitting technique for enhancing the flexural ductility and shear resistance of existing bridge columns. However, most retrofit techniques currently in vogue are essentially one-time fixes that do not address the issue of repairability following a seismic event. This paper reports the results of a research program investigating the performance of reinforced concrete bridge columns where the main objective is to control damage and ensure fast rehabilitation with minimum disruption to the traffic flow. Thus a retrofit for control and repairability of damage ( ReCARD) philosophy is developed and validated through experiments on near full-size bridge columns.
Application of Extreme Value Statistics to Annual Maximum Magnitudes in Jordan Employing a Mixture Distribution
Authors: Malkawi Abdallah I. Husein , Abdulla Fayez A. , Barakat Samer A. , Al-Sheriadeh Mohanned S.
Published: July 2003

The concept of extreme value mixture distribution (EVmix) has been implemented in this study to estimate maximum earthquake magnitude occurrence. The EVmix model is applied to annual maximum earthquake magnitude occurrence in Jordan and conterminous regions spanning over the period 1918 to 1997. The maximum likelihood method, in conjunction with the two optimization methods, was employed for determining the statistical parameters of the Gumbel's asymptotic distribution, i.e., GI, and the extreme value distributions EVIII and EVmix. The Simplex method of Nelder and Mead (1965) was found to be more successful in obtaining the maximum likelihood estimators of the three given distributions than the Newton-Raphson method. The difficulties inherent to the Newton-Raphson method were overcome by the Simplex method. It is shown in this study that the EVmix model fits the observed annual maxima far better than GI and EVIII models. In addition, the maximum likelihood estimators obtained using the Simplex method were used to calculate the earthquake risk for a given return period and a design lifetime of structures.