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November 2009

Volume 25, Issue 4, pp. 733-966

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Seismic Hazard Epistemic Uncertainty in the San Francisco Bay Area and Its Role in Performance-Based Assessment

Brendon A. Bradley

Earthquake Spectra 25, pp. 733-753 (2009); doi:http://dx.doi.org/10.1193/1.3238556 | Cited 1 time

Online Publication Date: 30 October 2009

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This paper investigates epistemic uncertainty in the results of seismic hazard analyses for the San Francisco Bay Area and their role in the broader picture of seismic performance assessment. Using the 2002 Working Group on California Earthquake Probabilities earthquake rupture forecast, epistemic uncertainty in the seismic hazard for several different intensity measures and sites in the San Francisco Bay Area is investigated. Normalization of the epistemic uncertainty for various sites and intensity measures illustrates that the uncertainty magnitude can be approximately estimated as a function of the mean exceedance probability. The distribution of the epistemic uncertainty is found to be dependent on the set of alternative ground-motion prediction equations used but is frequently well approximated by the lognormal distribution. The correlation in the hazard uncertainty is observed to be a function of the separation between the two different intensity levels, and a simple predictive equation is proposed based on the data analyzed. Three methods for the propagation of seismic hazard epistemic uncertainty are compared and contrasted using an example of the 30-year collapse probability of a structure. It is observed that, for this example, epistemic uncertainty in the collapse capacity is more influential than that in the seismic hazard.
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89.20.Kk Engineering
91.30.Px Earthquakes
91.30.Mv Strong motions and shock waves

Estimation of Lifeline Resilience Factors Based on Surveys of Japanese Industries

Yoshio Kajitani, M.EERI and Hirokazu Tatano

Earthquake Spectra 25, pp. 755-776 (2009); doi:http://dx.doi.org/10.1193/1.3240354

Online Publication Date: 30 October 2009

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This paper discusses the resilience factors of industrial sectors under lifeline (electricity, water, and gas) system disruptions. The resilience factor is one of the quantitative measurements of lifeline impacts, which focuses on the production output of some industrial sectors during lifeline disruptions. Recent studies have provided the detailed structure of business resilience that includes multiple resilience options, such as production rescheduling, inventories, and back-up generators. However, the impacts of these options on resilience factor are not thoroughly investigated due to the lack of data. In addition, resilience factor in previous study is assumed to be applied only to the single-lifeline disruption case, which is a limited case in large-scale disasters. In this study, the resilience factors for 27 industrial sectors are estimated based on the empirical surveys conducted in the Aichi and Shizuoka Prefectures, Japan, focusing on more rigorous characteristics of resilience. One particular contribution of this paper is introducing the resilience factor that considers individual and compound effects of available resilience options along with multiple lifeline disruptions.
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89.65.Gh Economics; econophysics, financial markets, business and management
89.20.Kk Engineering

Geoengineering and Seismological Aspects of the Niigata-Ken Chuetsu-Oki Earthquake of 16 July 2007

Robert Kayen, Scott J. Brandenberg, Brian D. Collins, Stephen Dickenson, Scott Ashford, Yohsuke Kawamata, Yasuo Tanaka, Hidetaka Koumoto, Norm Abrahamson, Lloyd Cluff, and Kohji Tokimatsu

Earthquake Spectra 25, pp. 777-802 (2009); doi:http://dx.doi.org/10.1193/1.3240397 | Cited 2 times

Online Publication Date: 30 October 2009

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The M6.6 Niigata-Ken Chuetsu-Oki earthquake of 16 July 2007 occurred off the west coast of Japan with a focal depth of 10 km, immediately west of Kashiwazaki City and Kariwa Village in southern Niigata Prefecture. Peak horizontal ground accelerations of 0.68 g were measured in Kashiwazaki City, as well as at the reactor floor level of the world’s largest nuclear reactor, located on the coast at Kariwa Village. Liquefaction of historic and modern river deposits, aeolian dune sand, and manmade fill was widespread in the coastal region nearest the epicenter and caused ground deformations that damaged bridges, embankments, roadways, buildings, ports, railways and utilities. Landslides along the coast of southern Niigata Prefecture and in mountainous regions inland of Kashiwazaki were also widespread affecting transportation infrastructure. Liquefaction and a landslide also damaged the nuclear power plant sites. This paper, along with a companion digital map database available at http://walrus.wr.usgs.gov/infobank/n/nii07jp/html/n-ii-07-jp.sites.kmz, describes the seismological and geo-engineering aspects of the event.
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91.30.Px Earthquakes

Response Modification Factors for RC Case-Study Buildings with Structural Walls

Taewan Kim, Douglas A. Foutch, M.EERI, James Wilcoski, M.EERI, and James M. LaFave, M.EERI

Earthquake Spectra 25, pp. 803-819 (2009); doi:http://dx.doi.org/10.1193/1.3240398

Online Publication Date: 30 October 2009

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A rational approach for determining the response modification factor, R, has been applied to reinforced concrete (RC) shear wall buildings designed under current codes and standards of practice. The approach is founded upon the performance-based evaluation framework from the SAC project; however, new values for various parameters were derived specifically for RC shear wall buildings because the SAC parameters were for steel moment frame buildings. Typical RC shear wall buildings were designed consisting of solid, flexure-dominated structural walls for lateral load resistance and a flat plate floor system for gravity loads. The performance of each building was then evaluated by calculating the confidence level of achieving the design objective. The buildings designed per the current R-value of 6 demonstrated good performances, meaning that the confidence levels of avoiding collapse were greater than the target value of 90%. The confidence levels for shear wall buildings with greater R-values were also determined, suggesting that further study could provide the basis for justifying an R-value of 7 for the special RC shear wall structural system.
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89.20.Kk Engineering
89.20.Bb Industrial and technological research and development

Modal Parameters for the Analysis of Inelastic Asymmetric-Plan Structures

Jui-Liang Lin and Keh-Chyuan Tsai, M.EERI

Earthquake Spectra 25, pp. 821-849 (2009); doi:http://dx.doi.org/10.1193/1.3238566 | Cited 3 times

Online Publication Date: 30 October 2009

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The conventional inelastic response spectra constructed by using the single-degree-of-freedom (SDOF) modal systems representing the relationship of roof translation versus base shear are short of the capability to accurately estimate rotational seismic demands for asymmetric-plan structures. This paper illustrates the inelastic response spectra for one-way asymmetric-plan structures constructed from the two-degrees-of-freedom (2DOF) modal systems. The 2DOF modal system can simultaneously represent the roof translation versus base shear and the roof rotation versus base torque relationships for each vibration mode of any one-way asymmetric-plan structure. Thus, the proposed inelastic response spectra are able to estimate not only the translational but also the rotational seismic demands. This new type of response spectra is named as the T-R response spectra. In order to construct the T-R inelastic response spectra, this research identifies three independent elastic 2DOF modal parameters: vibration period, Tn, frequency ratio, Ωθn, and modal eccentricity, en. The relationships between the inelastic 2DOF modal parameters and the strength ratio are established in this study. The ranges of the 2DOF modal parameter values are investigated for the general one-story, one-way, asymmetric-plan buildings. The translational and rotational constant-strength response spectra constructed from the 2DOF modal systems are illustrated. This paper demonstrates that the proposed inelastic response spectra are more suitable for computing the seismic demands of one-way asymmetric-plan structures than the conventional SDOF inelastic response spectra.
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89.20.Kk Engineering
89.20.Bb Industrial and technological research and development

Systematic Seismic Design for Manageable Loss in Wood-Framed Buildings

Shiling Pei and John W. van de Lindt, M.EERI

Earthquake Spectra 25, pp. 851-868 (2009); doi:http://dx.doi.org/10.1193/1.3240412 | Cited 1 time

Online Publication Date: 30 October 2009

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Light frame wood structures make up the vast majority of the residential building stock in the United States. Because of this, earthquake-induced losses for this category of building from a significant earthquake would have a substantial financial impact on the regional economy, as well as on the building owner. Current wood-framed structural design philosophy focuses only on life safety and only limits damage through implicit assumptions. The concept of loss-based seismic design is introduced in this paper with typical loss-based design statements explicitly formulated with the intent of addressing the concerns, e.g., financial loss, of the building end-user. The loss-based design procedure was established based on a loss estimation framework that relied on the existing concept of assembly-based vulnerability (ABV). With the help of an automated dynamic and loss analysis package developed for wood-framed structures (SAPWoodâ„¢) at Colorado State University, loss-based seismic design for a typical North American single family residential building was conducted for several different explicitly stated loss targets. The results from the numerical examples showed that loss-based seismic design for wood-framed structures is a viable concept that can serve as an important step in the evolution of end-user oriented, performance-based seismic design (PBSD).
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89.20.Kk Engineering
89.20.Bb Industrial and technological research and development

Updated Seismic Design Guidelines for Model Building Code of Mexico

Arturo Tena-Colunga, M.EERI, Ulises Mena-Hernández, Luis Eduardo Pérez-Rocha, Javier Avilés, Mario Ordaz, and Jorge Iván Vilar

Earthquake Spectra 25, pp. 869-898 (2009); doi:http://dx.doi.org/10.1193/1.3240413

Online Publication Date: 30 October 2009

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The Manual of Civil Structures (MOC), a model design code in Mexico, has been in the process of being updated, and the new version of this code was published in 2008. A major update from the 1993 version was performed in the chapter for the seismic design of building structures. This paper summarizes the most relevant changes of this building code and their relation to research efforts conducted within Mexico and worldwide to improve the seismic design of building structures. One goal is to make the guidelines as transparent as possible to users, so that the design process will be clearer to structural engineers.
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89.20.Kk Engineering
89.20.Bb Industrial and technological research and development

Nonlinear Seismic Torsional Pounding Between an Asymmetric Tower and a Barrier

X. X. Wei, L. X. Wang, and K. T. Chau

Earthquake Spectra 25, pp. 899-925 (2009); doi:http://dx.doi.org/10.1193/1.3207177

Online Publication Date: 30 October 2009

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Seismic torsional pounding between an asymmetric single-story tower and a neighboring barrier under harmonic ground excitation is modeled as the nonlinear Hertz contact in this paper. The governing equations of motion are numerically solved using the fourth-order Runge-Kutta method with an adaptive step size control. An analytical solution is obtained for the first time for a special case of periodic torsional pounding. Results of our numerical simulations reveal that torsional pounding tends to be much more complex and unpredictable than translational pounding, and most of them are either multiple or chaotic impacts. The maximum torsional impact velocity tends to be insensitive to the changes of separation distance and eccentricity as long as impact is developed. Although the analytical solution fails to predict the exact impact velocity of multiple torsional pounding, it does provide some useful insights into this complex phenomenon. The analytical solution succeeds in predicting the overall patterns as well as the abrupt jump of torsional impact velocity spectra.
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89.20.Kk Engineering
02.60.-x Numerical approximation and analysis
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ASCE-41 and FEMA-351 Evaluation of E-Defense Collapse Test

Bruce F. Maison, M.EERI, Kazuhiko Kasai, M.EERI, and Gregory Deierlein, M.EERI

Earthquake Spectra 25, pp. 927-953 (2009); doi:http://dx.doi.org/10.1193/1.3224159

Online Publication Date: 30 October 2009

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A welded steel moment-frame building is used to assess performance-based engineering guidelines. The full-scale four-story building was shaken to collapse on the E-Defense shake table in Japan. The collapse mode was a side-sway mechanism in the first story, which occurred in spite of a strong-column and weak-beam design. Computer analyses were conducted to simulate the building response during the experiment. The building was then evaluated using the Seismic Rehabilitation of Existing Buildings (ASCE-41) and Seismic Evaluation and Upgrade Criteria for Existing Welded Steel Moment-Frame Buildings (FEMA-351) for the collapse prevention performance level via linear and nonlinear procedures. The guidelines had mixed results regarding the characterization of collapse, and no single approach was superior. They mostly erred on the safe side by predicting collapse at shaking intensities less than that in the experiment. Recommendations are made for guideline improvements.
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89.20.Kk Engineering
81.70.Bt Mechanical testing, impact tests, static and dynamic loads
91.30.Mv Strong motions and shock waves
43.40.-r Structural acoustics and vibration
46.70.De Beams, plates, and shells
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Thomas Paulay 1923-2009

Hugo Bachmann, Athol Carr, David Hopkins, Shunsuke Otani, Gregory Paulay, Nigel Priestley, and Robert Reitherman

Earthquake Spectra 25, pp. 955-962 (2009); doi:http://dx.doi.org/10.1193/1.3238565

Online Publication Date: 30 October 2009

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Abstract Unavailable
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01.60.+q Biographies, tributes, personal notes, and obituaries
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In Recognition

EDITORIAL BOARD

Earthquake Spectra 25, pp. 963-966 (2009); doi:http://dx.doi.org/10.1193/1.3256014

Online Publication Date: 30 October 2009

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Abstract Unavailable
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01.60.+q Biographies, tributes, personal notes, and obituaries
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