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November 2003

Volume 19, Issue 4, pp. 733-1008

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A Framework to Quantitatively Assess and Enhance the Seismic Resilience of Communities

Michel Bruneau, Stephanie E. Chang, Ronald T. Eguchi, George C. Lee, Thomas D. O’Rourke, Andrei M. Reinhorn, Masanobu Shinozuka, Kathleen Tierney, William A. Wallace, and Detlof von Winterfeldt

Earthquake Spectra 19, pp. 733-752 (2003); doi:http://dx.doi.org/10.1193/1.1623497 | Cited 23 times

Online Publication Date: 13 November 2003

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This paper presents a conceptual framework to define seismic resilience of communities and quantitative measures of resilience that can be useful for a coordinated research effort focusing on enhancing this resilience. This framework relies on the complementary measures of resilience: “Reduced failure probabilities,” “Reduced consequences from failures,” and “Reduced time to recovery.” The framework also includes quantitative measures of the “ends” of robustness and rapidity, and the “means” of resourcefulness and redundancy, and integrates those measures into the four dimensions of community resilience—technical, organizational, social, and economic—all of which can be used to quantify measures of resilience for various types of physical and organizational systems. Systems diagrams then establish the tasks required to achieve these objectives. This framework can be useful in future research to determine the resiliency of different units of analysis and systems, and to develop resiliency targets and detailed analytical procedures to generate these values.
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89.60.Gg Impact of natural and man-made disasters
91.30.-f Seismology
89.20.Kk Engineering

Seismic Damage Characteristics of Cripple Walls

Y. H. Chai and Tara C. Hutchinson

Earthquake Spectra 19, pp. 753-778 (2003); doi:http://dx.doi.org/10.1193/1.1621886

Online Publication Date: 13 November 2003

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Significant losses were reported for wood-framed construction during past earthquakes in California due to damage or collapse of cripple walls in single-family residential buildings. A common cripple wall failure involves the upper stories shifting laterally over the “soft” unbraced cripple wall, causing the building to drop vertically, which in turn causes fracture of sewer, water, and gas lines, and often leads to irreparable loss of the building. This paper presents results from a series of in-plane level and stepped cripple wall tests, which were conducted as a part of the CUREE-Caltech Woodframe Project. Specimens with details representative of current retrofit and new construction were tested using displacement histories recommended for near-fault and ordinary ground motions. Code requirements and previous research on cripple walls are first reviewed, followed by a presentation of the damage characteristics of cripple walls. The effects of loading histories on the response of cripple walls are also described.
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89.20.Kk Engineering
46.70.Lk Other structures
91.30.-f Seismology

Laboratory Equipment: Estimating Losses and Mitigation Costs

Mary C. Comerio and John C. Stallmeyer

Earthquake Spectra 19, pp. 779-797 (2003); doi:http://dx.doi.org/10.1193/1.1622704

Online Publication Date: 13 November 2003

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The building code provides seismic design criteria for the structural and nonstructural systems in most building types, but there are no regulations to govern the installation of a building’s contents. In certain building types, such as museums, libraries, high-tech fabrication facilities, and research laboratories, the contents are valuable or critical to operations, or both. This paper focuses on strategies for improving seismic performance for laboratory furnishings and equipment. A survey of science laboratories at the University of California, Berkeley, served as the basis for constructing a simplified taxonomy of laboratory equipment, mitigation designs, and cost estimates. Case studies of five laboratories in different disciplines, and one biological science laboratory building, demonstrate mitigation techniques and potential installation costs. The case studies also highlight the importance of considering the contents separately from the structural and nonstructural systems when developing vulnerability estimates for certain building types in earthquake loss modeling.
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89.20.Kk Engineering
89.60.Gg Impact of natural and man-made disasters
91.30.-f Seismology

SDOF Demand Index Relationships for Performance-Based Seismic Design

Kenneth T. Farrow and Yahya C. Kurama

Earthquake Spectra 19, pp. 799-838 (2003); doi:http://dx.doi.org/10.1193/1.1622955 | Cited 9 times

Online Publication Date: 13 November 2003

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This paper investigates design relationships to estimate the following four seismic demand indices for single-degree-of-freedom (SDOF) systems: (1) the peak displacement ductility demand, μ; (2) the cumulative plastic displacement ductility demand, μp; (3) the residual displacement ductility demand, μr; and (4) the number of yield events, ny. The main objectives of the study are (1) to develop relatively simple regression relationships that can be used to estimate mean values of these demand indices; and (2) to investigate the effects of structure yield strength, hysteretic behavior, fundamental period, site soil characteristics, seismic demand level, site seismicity, and epicentral distance on these relationships. It is shown that the correlation between μ and the other demand indices is usually relatively strong. In some cases, the cross-correlations between the demand indices are weak, indicating that these indices carry independent measures of seismic demand.
Show PACS
89.20.Kk Engineering
46.70.-p Application of continuum mechanics to structures
91.30.-f Seismology

Evaluation of Simple Methods for Estimating Drift of Reinforced Concrete Buildings Subjected to Earthquakes

Adolfo Matamoros, JoAnn Browning, and Maren Luft

Earthquake Spectra 19, pp. 839-861 (2003); doi:http://dx.doi.org/10.1193/1.1623781

Online Publication Date: 13 November 2003

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A simplified procedure to estimate drift based on the area of load-resisting elements is presented and its results are compared with those of the equivalent-period method and the target-displacement method as defined in FEMA-273 (1997). All three methods are used to estimate the upper-bound drift based on simple parameters that represent the lateral stiffness and mass of a structure. The accuracy of the methods was evaluated using experimental results from 152 earthquake simulator tests found in the literature. Coefficients of variation for the measured-to-calculated drift ratios ranged between 0.6 and 0.75, indicating that the accuracy of the drift estimates afforded by the three methods was similar for the set of test results evaluated. Additional comparisons are presented for the proposed method based on 720 nonlinear analyses of notional frames and the measured response of an instrumented building.
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89.20.Kk Engineering
46.70.Lk Other structures
91.30.-f Seismology

The Seismic Design and Performance of Reinforced Concrete Beam-Column Knee Joints in Buildings

Leslie M. Megget

Earthquake Spectra 19, pp. 863-895 (2003); doi:http://dx.doi.org/10.1193/1.1623782

Online Publication Date: 13 November 2003

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The seismic performance of eleven half-scale and three full-sized reinforced concrete beam-column knee joints was tested under inelastic cyclic loading. Twelve joints were designed to the current New Zealand Concrete Standard, NZS 3101 while the remaining two were designed to the 1964 New Zealand Code, which contained few seismic provisions. All the 1995 designs approached or exceeded their nominal beam strengths in both directions and only degraded in strength at displacement ductility factors greater than 2, while the 1960 designs failed prematurely in joint shear at about 70% of the beam nominal strengths. Many of the half-scale joints failed when cover concrete split off in the joint zone, allowing loss of anchorage and slip of the top beam bars. Two full-scale joints were designed to carry the maximum specified code joint shear stress (0.2 fc′), and one subsequently failed due to joint shear when the concrete compressive strength did not reach the specified design value. A third full-size joint was tested with distributed beam reinforcement. This joint performed in a ductile manner to displacement ductility 4 but failed in the second cycle at that displacement, due to buckling of several rows of beam bars.
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89.20.Kk Engineering
46.70.De Beams, plates, and shells
91.30.-f Seismology

“Exact” Three-Dimensional Linear and Nonlinear Seismic Analysis of Structures with Two-Dimensional Models

Michael Mehrain and Farzad Naeim

Earthquake Spectra 19, pp. 897-912 (2003); doi:http://dx.doi.org/10.1193/1.1623498

Online Publication Date: 13 November 2003

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This paper presents a modeling technique by which a complete three-dimensional (3-D) structural analysis of a structure can be performed using two-dimensional (2-D) models, and hence 2-D software. The approach includes the effect of torsion, walls perpendicular and inclined to the direction of motion as well as walls with L, T, and H shapes in plan. Diaphragm displacements are easily modeled. The method can be used with linear and nonlinear analysis. Nonlinearity in the diaphragms can also be modeled with relative ease. Furthermore, unlike the conventional analysis that requires two 2-D models, one in each direction of motion, to model the 3-D structure, this approach requires only a single model.
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89.20.Kk Engineering
46.70.-p Application of continuum mechanics to structures
91.30.Bi Seismic sources (mechanisms, magnitude, moment frequency spectrum)

A Comparative Study of U.S.-Japan Seismic Design of Highway Bridges: I. Design Methods

W. P. Yen, J. D. Cooper, S. W. Park, S. Unjoh, T. Terayama, and H. Otsuka

Earthquake Spectra 19, pp. 913-932 (2003); doi:http://dx.doi.org/10.1193/1.1623783 | Cited 1 time

Online Publication Date: 13 November 2003

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This paper summarizes the results of a comparative study on seismic design of highway bridges jointly undertaken by the U.S. Federal Highway Administration and Japan’s Public Works Research Institute. The seismic design specifications for highway bridges of the two countries are reviewed and compared with respect to their design philosophies and procedures. Some major design parameters including design seismic forces, response modification factors and minimum support lengths are addressed in detail. The differences between the two specifications are illustrated via a design example of a reinforced concrete column for simple, two-span bridges common in both countries. Three different scale models of the column are designed in accordance with the seismic design specifications of the United States and Japan, and tested on a shake table for their comparative seismic performance. The results of the shake table tests are discussed separately in a companion paper.
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89.20.Kk Engineering
46.70.Lk Other structures
91.30.-f Seismology

A Comparative Study of U.S.-Japan Seismic Design of Highway Bridges: II. Shake-Table Model Tests

S. W. Park, W. P. Yen, J. D. Cooper, S. Unjoh, T. Terayama, and H. Otsuka

Earthquake Spectra 19, pp. 933-958 (2003); doi:http://dx.doi.org/10.1193/1.1623189 | Cited 1 time

Online Publication Date: 13 November 2003

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As part of a comparative study on the United States’ and Japan’s seismic design of highway bridges, three scale models of a reinforced-concrete bridge column are tested on a shake table for their seismic performance. Three specimens, one based on the ductility design method (U.S.) and the others on the working stress design method (Japan), are subjected to a set of successive earthquake ground motions with varying intensities. All three specimens showed good performance; however, the specimen of ductility design experienced less damage than those of working stress design. Analysis of test results showed that structural degradation in each column closely correlates with decrease in the transverse stiffness, increase in the hysteretic energy dissipation, and increase in the vibration period, of the column. Two damage indices, based respectively on effective flexibility and weighted cumulative hysteretic energy, are used to indicate the progression of structural degradation in a reinforced-concrete bridge column subjected to successive earthquake ground motions.
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89.20.Kk Engineering
46.70.Lk Other structures
91.30.-f Seismology

Equivalent Lateral Force and Modal Analysis Procedures of the 2000 NEHRP Provisions for Buildings with Damping Systems

Andrew S. Whittaker, Michael C. Constantinou, Oscar M. Ramirez, Martin W. Johnson, and Christis Z. Chrysostomou

Earthquake Spectra 19, pp. 959-980 (2003); doi:http://dx.doi.org/10.1193/1.1622391 | Cited 6 times

Online Publication Date: 13 November 2003

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Equivalent lateral force and modal analysis procedures for yielding buildings with damping systems were developed, validated, and incorporated in the 2000 NEHRP Provisions. The technical basis for each procedure is described in the paper together with the simplifications adopted for inclusion in the Provisions. Procedures for calculating the effective damping and effective period and higher mode damping ratios for buildings equipped with yielding, viscoelastic, linear viscous, and nonlinear viscous damping devices are presented.
Show PACS
89.20.Kk Engineering
46.40.Ff Resonance, damping, and dynamic stability
46.70.-p Application of continuum mechanics to structures
91.30.-f Seismology

Validation of the 2000 NEHRP Provisions’ Equivalent Lateral Force and Modal Analysis Procedures for Buildings with Damping Systems

Oscar M. Ramirez, Michael C. Constantinou, Andrew S. Whittaker, Charles A. Kircher, Martin W. Johnson, and Christis Z. Chrysostomou

Earthquake Spectra 19, pp. 981-999 (2003); doi:http://dx.doi.org/10.1193/1.1622392 | Cited 9 times

Online Publication Date: 13 November 2003

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Equivalent lateral force and modal analysis procedures for yielding buildings with damping systems were developed, validated, and incorporated in the 2000 NEHRP Provisions. Key to the implementation of the procedures was the validation process that demonstrated the accuracy of the proposed procedures. The procedures for implementing yielding, viscoelastic, linear viscous, and nonlinear viscous dampers were tested using the results of nonlinear response-history analysis on sample three- and six-story frames and were found to be robust.
Show PACS
89.20.Kk Engineering
46.40.Ff Resonance, damping, and dynamic stability
46.70.-p Application of continuum mechanics to structures
91.30.-f Seismology
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On the Discussion of the Damping Reduction Factors in the Constant Acceleration Region for ATC-40 and FEMA-273

Yu-Yuan Lin, Meng-Hao Tsai, and Kuo-Chun Chang

Earthquake Spectra 19, pp. 1001-1006 (2003); doi:http://dx.doi.org/10.1193/1.1623784

Online Publication Date: 13 November 2003

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According to the ATC-40 (1996) and FEMA-273 (1997) documents, the damping reduction factors for the constant acceleration range of the design response spectra are larger than those for the constant velocity range of those. This trend is contrary to the results obtained from several recent studies and may lead to underestimates of the high-damped design response spectra. This paper points out the issue and suggests further examinations of the factor in the constant acceleration region with potential revision to design practice.
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89.20.Kk Engineering
46.70.-p Application of continuum mechanics to structures
46.40.Ff Resonance, damping, and dynamic stability
91.30.-f Seismology
01.78.+p Science and government (funding, politics, etc.)
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Moments of Resistance

Mark Taylor, Author, Julieanna Preston, Author, Andrew Charleson, Author, and Mary Comerio, Reviewer, M.EERI

Earthquake Spectra 19, pp. 1007-1008 (2003); doi:http://dx.doi.org/10.1193/1.1622393

Online Publication Date: 13 November 2003

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Abstract Unavailable
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01.30.Vv Book reviews
01.30.Ee Monographs and collections
89.20.Kk Engineering
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