bluuebunny/crossref_metadata_2025 huggingface dataset:
Site-Dependent Building Response in Singapore to Long-Distance Sumatra Earthquakes
Authors: Pan Tso-Chien
Published: July 2003

Singapore is a city state located in a low seismicity area with mild winds. The country is a classic example of low seismic hazard and high exposure scenario. It is about 400 km away from a highly active earthquake belt, the Sumatra subduction complex, where great earthquakes have occurred in the past. Twenty-seven earthquakes have been reportedly felt in Singapore since the British settlement in 1819. The frequency of these felt events seems to be rising with time as the country develops. The response of a building to long-distance earthquakes is dependent on the type of structural systems and the local geological conditions. Tall buildings founded on Quaternary deposit, i.e. the Kallang Formation, are particularly apt to respond to the long-distance Sumatra earthquakes. Microtremor measurement results correlate well with the geological conditions and give evidence to the phenomenon of site dependent building response in Singapore to the long-distance Sumatra earthquakes.
Estimation of Earthquake Losses to Buildings
Authors: Kircher Charles A. , Reitherman Robert K. , Whitman Robert V. , Arnold Christopher
Published: July 2003

This paper describes methods for estimating building losses that were developed for the FEMA/NIBS earthquake loss estimation methodology (Whitman et al., 1997). These methods are of a new form and represent a significant step forward in the prediction of earthquake impacts. Unlike previous building loss models that are based on Modified Mercalli Intensity, the new methods use quantitative measures of ground shaking (and ground failure) and analyze model building types in a similar manner to the engineering analysis of a single structure. Direct economic losses predicted by these new methods for typical single-family homes compare well with observed losses to Los Angeles County residences damaged by the 1994 Northridge Earthquake.
A Replacement for the 30%, 40%, and SRSS Rules for Multicomponent Seismic Analysis
Authors: Menun Charles , Der Kiureghian Armen
Published: July 2003

A response spectrum rule for combining the contributions from three orthogonal components of ground motion to the maximum value of a response quantity is presented. This rule, denoted CQC3, is compared to the 30% and 40% rules and the square-root-of-sum-of-squares (SRSS) rule currently specified in many design codes. It is shown that these current rules are special cases of the CQC3 rule, when certain conditions regarding the nature of the ground motion or the structural response are satisfied. Because these conditions are not always satisfied, it is argued that the CQC3 rule should be adopted as a general rule for the multicomponent combination problem. The CQC3 rule additionally offers a simple formula for determining the most critical orientation of the ground motion components for each response quantity of interest. The CQC3 rule is computationally simple and easy to implement in standard dynamic analysis codes.
Logic Trees, Sensitivity Analyses, and Data Reduction in Probabilistic Seismic Hazard Assessment
Authors: Rabinowitz Nitzan , Steinberg David M. , Leonard Gideon
Published: July 2003

This article explains the essential duality between logic tree analysis and sensitivity analysis in probabilistic seismic hazard assessment. The results of a logic tree analysis can be used to carry out a sensitivity analysis. More important, a preliminary sensitivity analysis can be used to focus attention on those parameters that have the largest effects on assessed hazard. This information can be of great value in the construction of a logic tree. Thus we advocate a two-stage process that begins with a sensitivity analysis and then proceeds to the construction of a logic tree.
The Rinaldi Strong Motion Accelerogram of the Northridge, California Earthquake of 17 January 1994
Authors: Trifunac Mihailo D. , Todorovska Maria I. , Lee Vincent W.
Published: July 2003

The Rinaldi record of the 1994 Northridge earthquake is one of the most important strong motion records in earthquake engineering (largest recorded horizontal peak ground velocity in the western United States, ∼170 cm/s). Digitization of this record was not straightforward because of numerous stalls and malfunction of the half-second pulse relays. It was digitized and processed for the Los Angeles Department of Water and Power soon after the earthquake, and was recently redigitized and reprocessed. This paper presents the results of the recent digitization and processing and a comparison of the two digital versions of the record. The “new” version differs from the “old” version in the number of stalls corrected for (17 versus one stall), total length of digitized traces (∼20 s versus ∼15 s), and amplitudes of some high frequency acceleration peaks (in the “old” version, some high frequency peaks have been underestimated). The peak amplitudes of corrected acceleration, velocity and displacement, and the linear response spectrum amplitudes are not significantly different. However, the two digital interpretations have different time scales, because of the difference in the number of stalls accounted for.
Performance of Solid Waste Landfills in Earthquakes
Authors: Matasovic Neven , Kavazanjian Edward , Anderson Robert L.
Published: July 2003

Interpretation and analysis of observational data on the performance of solid waste landfills during earthquakes is the most reliable source of information on the seismic response of solid waste landfills. The data from several major California earthquakes indicate that the general performance of landfills during earthquakes is from good to excellent. None of the landfills on which observational data is available experienced major earthquake-induced damage. Recorded strong ground motion data indicate that amplification of both peak and spectral accelerations can occur at the top of a landfill. This, combined with the fact that only a limited number of landfills with geosynthetic liners and no landfill with a geosynthetic cover have been subjected to strong ground motions, indicate that attention to detail is warranted in the design of modern, geosynthetic-lined and/or covered landfills in areas of high seismicity.
Vertical Response of Twelve Structures Recorded during the Northridge Earthquake
Authors: Bozorgnia Yousef , Mahin Stephen A. , Brady A. Gerald
Published: July 2003

This paper summarizes the results of a study on vertical response of twelve instrumented structures recorded during the Northridge earthquake. The selected structures include buildings ranging in height from 2 to 14 stories, located within a distance range of 8 to 71 km from the causative fault of the Northridge earthquake. They include four steel buildings, five concrete structures and three base-isolated buildings. The recorded peak vertical structural accelerations are found to be larger than those at the base by a factor of 1.1 to 6.4. The identified lowest vertical frequencies of the structural members and systems of all the twelve structures are within the frequency range of 3.9 to 13.3 Hz (period range of 0.075 to 0.26 sec). For the structures located in the near-source region, this period range may correspond to a range of high vertical spectral accelerations.
Spectral Comparison of Vertical and Horizontal Seismic Strong Ground Motions in Alluvial Basins
Authors: Amirbekian Rouben V. , Bolt Bruce A.
Published: July 2003

We analyze observations from the SMART2 array and the 1994 Northridge, California earthquake of spectral differences between vertical and horizontal strong seismic motions in alluvial basins. Our explanation is that the most energetic of such high-frequency vertical ground accelerations are generated by S-to-P seismic wave conversion within the transition zone between the underlying bedrock and the overlying sedimentary layers. The differences in combined scattering and anelastic attenuation for P and S waves lead to the observed spectral differences of the vertical motions between rock and deep alluvium sites. This model also accounts for the frequency content differences between the vertical and horizontal motions at sites in alluvial basins than at rock sites at similar distance ranges. The high-frequency cutoff of the acceleration power spectrum, fmax, is a useful comparison parameter. The results help in computing matched sets of synthetic ground motions above 2 Hz at alluvial sites.
Statistical Analysis of Bridge Damage Data from the 1994 Northridge, CA, Earthquake
Authors: Basöz Nesrin I. , Kiremidjian Anne S. , King Stephanie A. , Law Kincho H.
Published: July 2003

This paper presents the significant findings from a study on damage to bridges during the January 17, 1994 Northridge, CA earthquake. The damage and repair cost data were compiled in a database for bridges in the Greater Los Angeles area. Observed damage data for all bridges were discriminated by structural characteristics. The analyses of data on bridge damage showed that concrete structures designed and built with older design standards were more prone to damage under seismic loading. Repair and/or reconstruction of collapsed structures formed seventy five percent of the total estimated repair cost. Peak ground acceleration values were also estimated at all bridge locations as part of this study. Empirical relationships between ground motion and bridge damage, and repair cost ratio were developed in the form of fragility curves and damage probability matrices, respectively. A comparison of the empirical and available ground motion-damage relationships demonstrated that the relationships that are currently in use do not correlate well to the observed damage.
Shear Resonance Frequencies of Alluvial Valleys by Rayleigh's Method
Authors: Paolucci Roberto
Published: July 2003

A simple approach based on Rayleigh's method has been used for the fast estimation of the shear resonance frequencies of alluvial valleys. After an example considering a 1-D non-homogeneous configuration, the method is applied to 2-D and 3-D homogeneous simple-shaped valleys, for which numerical solutions exist in the literature. The application of the proposed method to deep non-homogeneous sedimentary basins is then illustrated, showing that even in a rather complex soil configuration the prediction errors do not exceed about 20%. If one considers the uncertainties related to the determination of the mechanical properties of a real soil configuration, this prediction is quite reasonable. Furthermore, the predicted fundamental frequency always provides an upper limit of the true value. Although the predicted results are not very accurate, the proposed procedure may be helpful in several practical applications, such as in the case of complex geological configurations, where the problem exists of assessing in which frequency band 1-D resonance will differ significantly from the 2-D or 3-D one. This is important to decide whether performing more sophisticated analyses of site effects and whether the use of standard code spectral shapes is appropriate.
Seismic Response of Unanchored Bodies
Authors: Shao Yuan , Tung C. C.
Published: July 2003

This paper is concerned with the response of a rigid body subjected to base excitation. Using analytical and numerical methods of investigation, the results are presented in a series of graphs giving (1) the criteria for initiation of various modes (rest, slide, rock and slide-rock) of response and, using an ensemble of 75 real earthquake acceleration records, (2) the mean plus standard deviation of the distance of sliding relative to the base and (3) the probability of overturning during rocking. Based on the results in (3), two tables are prepared which give, corresponding to probability of overturning equal to 0.16 and 0.5, allowable peak base acceleration.
New Site Coefficients and Site Classification System Used in Recent Building Seismic Code Provisions
Authors: Dobry R. , Borcherdt R. D. , Crouse C. B. , Idriss I. M. , Joyner W. B. , Martin G. R. , Power M. S. , Rinne E. E. , Seed R. B.
Published: July 2003

Recent code provisions for buildings and other structures (1994 and 1997 NEHRP Provisions, 1997 UBC) have adopted new site amplification factors and a new procedure for site classification. Two amplitude-dependent site amplification factors are specified: Fa for short periods and Fv for longer periods. Previous codes included only a long period factor S and did not provide for a short period amplification factor. The new site classification system is based on definitions of five site classes in terms of a representative average shear wave velocity to a depth of 30 m (V¯s). This definition permits sites to be classified unambiguously. When the shear wave velocity is not available, other soil properties such as standard penetration resistance or undrained shear strength can be used. The new site classes denoted by letters A - E, replace site classes in previous codes denoted by S1 - S4. Site classes A and B correspond to hard rock and rock, Site Class C corresponds to soft rock and very stiff / very dense soil, and Site Classes D and E correspond to stiff soil and soft soil. A sixth site class, F, is defined for soils requiring site-specific evaluations. Both Fa and Fv are functions of the site class, and also of the level of seismic hazard on rock, defined by parameters such as Aa and Av ( 1994 NEHRP Provisions), Ss and Sl ( 1997 NEHRP Provisions) or Z ( 1997 UBC). The values of Fa and Fv decrease as the seismic hazard on rock increases due to soil nonlinearity. The greatest impact of the new factors Fa and Fv as compared with the old S factors occurs in areas of low-to-medium seismic hazard. This paper summarizes the new site provisions, explains the basis for them, and discusses ongoing studies of site amplification in recent earthquakes that may influence future code developments.
NEHRP Guidelines and Commentary for the Seismic Rehabilitation of Buildings
Authors: Shapiro Daniel , Rojahn Christopher , Reaveley Lawrence D. , Smith James R. , Morelli Ugo
Published: July 2003

Based on the conclusion that the primary barrier to widespread seismic rehabilitation of buildings in the United States was the lack of a consensus-backed, nationally applicable, professionally accepted rehabilitation standard, the Federal Emergency Management Agency supported the development of the NEHRP Guidelines and Commentary for the Seismic Rehabilitation of Buildings (FEMA 273 and 274). A six-year effort by a team of experienced professional practitioners and university researchers who were motivated to produce a standard that specifically addressed the differences in designing for seismic resistance in new buildings, as opposed to existing buildings, resulted in the NEHRP Guidelines and Commentary for the Seismic Rehabilitation of Buildings. These NEHRP Guidelines will provide the tools for design professionals of varying expertise in seismic design to design economical and appropriate seismic rehabilitation for buildings of essentially any size, commonly used building material and configuration.
Seismic Evaluation and Retrofit of Concrete Buildings: A Practical Overview of the ATC 40 Document
Authors: Comartin Craig D. , Niewiarowski Richard W. , Freeman Sigmund A. , Turner Fred M.
Published: July 2003

The Applied Technology Council (ATC), with funding from the California Seismic Safety Commission developed the document, Seismic Evaluation and Retrofit of Concrete Buildings, commonly referred to as ATC 40. This two-volume, 612-page report provides a recommended procedure for the seismic evaluation and retrofit of concrete buildings. Although the focus is specifically on concrete buildings, the document provides information on emerging techniques applicable to most building types. This paper provides an introduction and overview of the document. The conceptual basis of the procedures is performance-based design using nonlinear static structural analysis. The ATC 40 document comprises a practical guide to the entire evaluation and retrofit process. Topics include performance objectives, seismic hazard, determination of deficiencies, retrofit strategies, quality assurance procedures, nonlinear static analysis using the capacity spectrum method, modeling recommendations, foundation effects, and response limits.
Evaluation of Earthquake-Damaged Concrete and Masonry Wall Buildings
Authors: Maffei Joe , Comartin Craig D. , Kehoe Brian , Kingsley Gregory R. , Lizundia Bret
Published: July 2003

Efforts at improving earthquake recovery policies have been hampered by a lack of criteria and standards for evaluating and repairing damaged buildings. The Applied Technology Council has developed a performance-based methodology for the evaluation of earthquake-damaged concrete wall buildings and masonry wall buildings, recently published as FEMA 306/307/308. The methodology provides a way to quantify damage in terms of loss of seismic performance capability. It also provides guidelines for remedial measures to restore or improve seismic performance capability. In this methodology, the expected future seismic performance of a building is evaluated in its pre-event, damaged, and repaired conditions. Following the nonlinear static analysis procedure, displacement demands and capacities of the structure are used as indices of seismic performance. Identifying the governing mechanism of nonlinear deformation and the behavior mode of a structure and its components is shown to be a necessary first step towards evaluating expected seismic performance, interpreting indications of damage, and assessing their significance. The methodology provides a technical resource for understanding how buildings respond seismically on both global and component levels, and gives a basis for formulating post-earthquake policies.
Adaptive Spectra-Based Pushover Procedure for Seismic Evaluation of Structures
Authors: Gupta Balram , Kunnath Sashi K.
Published: July 2003

The estimation of inelastic seismic demands using nonlinear static procedures, or pushover analyses, are inevitably going to be favored by practicing engineers over nonlinear time-history methods. While there has been some concern over the reliability of static procedures to predict inelastic seismic demands, improved procedures overcoming these drawbacks are still forthcoming. In this paper, the potential limitations of static procedures, such as those recommended in FEMA 273, are highlighted through an evaluation of the response of instrumented buildings that experienced strong ground shaking in the 1994 Northridge earthquake. A new enhanced adaptive “modal” site-specific spectra-based pushover analysis is proposed, which accounts for the effect of higher modes and overcomes the shortcomings of the FEMA procedure. Features of the proposed procedure include its similarity to traditional response spectrum-based analysis and the explicit consideration of ground motion characteristics during the analysis. It is demonstrated that the proposed procedure is able to reasonably capture important response attributes, such as interstory drift and failure mechanisms, even for structures with discontinuities in strength and/or stiffness that only a detailed nonlinear dynamic analysis could predict.
Building Period Formulas for Estimating Seismic Displacements
Authors: Chopra Anil K. , Goel Rakesh K.
Published: July 2003

Traditionally, empirical formulas for building period recommended for code applications are intentionally calibrated to underestimate the period in order to estimate base shear conservatively. At a shorter period, the seismic displacements are smaller, however, and hence underestimated. This note discusses this issue and recommends formulas for estimating seismic displacements of buildings.
Performance Assessment for a Reinforced Concrete Frame Building
Authors: Browning JoAnn , Li Y. Roger , Lynn Abraham , Moehle Jack P.
Published: July 2003

This paper evaluates the performance of a seven-story reinforced concrete frame building that was severely damaged during the 1994 Northridge, California, earthquake. The building was designed and constructed in the 1960s and contains details that are typical of that construction era in the western United States. The building sustained severe damage that included column shear failures. The building was analyzed independently by three research teams using analysis methodólogies that were similar in concept but different in details. An objective of each analysis was to correlate observed and calculated performance. The different analyses were successful to varying degrees. The results provide a test case of the effectiveness of various seismic performance assessment methodologies.
Validated Estimation of Response Spectra for the 1980 Irpinia Earthquake in the Eastern Area of Naples
Authors: Nunziata C. , Costa G. , Marrara F. , Panza G. F.
Published: July 2003

The seismic ground motion of a test area in the eastern district of Naples is computed with a hybrid technique based on the mode summation and the finite difference methods. Synthetic seismograms are validated with the 1980 Irpinia earthquake, a good example of strong shaking for Naples, recorded 10km from the modeled sites. Realistic SH and P-SV wave seismograms are computed along geological cross sections representative of the area. As expected, the sedimentary cover causes an increase of the signal's amplitudes along the radial and transverse components. The spectral amplification of the vertical motion is generally negligible; instead, that of the horizontal motion ranges between 2 and 5 in the 0.7-2.2 Hz frequency range. Average and maximum spectral amplifications are considered along the different geological cross sections and acceleration response spectra for the Irpinia earthquake are evaluated in order to formulate appropriate design spectra and improvements to the building code.
Dynamic Racking Performance of an Earthquake-Isolated Curtain Wall System
Authors: Brueggeman Jamie L. , Behr Richard A. , Wulfert Heinrich , Memari Ali M. , Kremer Paul A.
Published: July 2003

Dynamic racking tests, coupled with air leakage tests, were performed on fullsize specimens of a new, Earthquake-Isolated Curtain Wall System and a widely used, conventional curtain wall system (used as an experimental control). Dynamic racking tests simulated seismic movements that could be imposed upon a curtain wall system as a result of interstory drifts. Air leakage tests were performed as an indicator of serviceability performance of both curtain wall systems during the dynamic racking tests. The Earthquake-Isolated Curtain Wall System demonstrated strongly superior performance in terms of both serviceability (glass cracking and air leakage) and life safety (glass fallout). The conventional system exhibited vulnerability to annealed monolithic glass cracking and glass fallout at dynamic racking drift indices of 1.9% and 3.1%, respectively. No glass damage was observed in the earthquake-isolated system up to the dynamic racking displacement limit of the test facility, which corresponded to a drift index of 4.9%. Air leakage rates through vision panels in the conventional system remained constant up to a drift index of 1.9%, after which the air leakage rates increased rapidly. In contrast, air leakage rates through vision panels in the earthquake-isolated system remained unchanged up to the 4.9% drift index capacity of the test facility.
Spectral Displacement Demands of Stiffness- and Strength-Degrading Systems
Authors: Song Jong-Keol , Pincheira JoséA.
Published: July 2003

The effect of stiffness and strength degradation on the maximum inelastic displacement of single-degree-of-freedom (SDOF) systems was investigated. The SDOF model included strength and stiffness degradation with increasing deformation amplitude and upon reversal of loading cycles. Pinching of the hysteresis loops was also considered. Spectral displacements were calculated for oscillators with a myriad of degrading characteristics subjected to twelve ground motions on rock, firm and soft soils. The results show that the maximum displacements of degrading oscillators are, on average, larger than those of nondegrading systems. The displacement amplification varies significantly with the period, strength coefficient, degradation rate, and ground motion considered. Nonetheless, the amplification due to the degradation characteristics of the system is much more important in the short period range where average amplification factors of two or three are credible. The amplification factors proposed by ATC 33 provided conservative estimates for oscillators with periods greater than 0.3 seconds subjected to motions on rock or firm soil. On soft soils, a good correlation was found for periods greater than 1.5 seconds. At shorter periods, the ATC 33 factors underestimate the displacement amplification.
Seismic Design of Lightweight Metal Building Systems
Authors: Mays Timothy Wayne
Published: July 2003

As a result of failures uncovered after the Northridge earthquake, the AISC Seismic Provisions for Structural Steel Buildings has become extremely stringent in its design provisions for moment frame structures. Although the changes are justified, they are not necessary for every type of building system. Some structures can be safely designed to resist earthquake forces elastically without concern of structural collapse. Metal buildings are typically lightweight, and small inertia forces from the design earthquake will not usually result in an inelastic response of a system that is properly designed to resist wind forces. In this paper, metal building systems are analyzed using an equivalent lateral force method and a linear time history analysis to show that typical metal building systems will respond elastically to the design earthquake. Specifically, using the International Building Code along with the aforementioned document, it is shown in the following sections that for lightweight metal building structures, adherence to the AISC Seismic Provisions for Structural Steel Buildings is not required in most cases except for locations on the West Coast and a few regions east of the Rocky Mountains. Elastic design methodology is discussed and design recommendations applicable to metal building systems are provided.
An Empirical Geotechnical Seismic Site Response Procedure
Authors: Rodríguez-Marek Adrián , Bray Jonathan D. , Abrahamson Norman A.
Published: July 2003

A simplified empirically based seismic site response evaluation procedure that includes measures of the dynamic stiffness of the surficial materials and the depth to bedrock as primary parameters is introduced. This geotechnical site classification scheme provides an alternative to geologic-based and shear wave velocity-based site classification schemes. The proposed scheme is used to analyze the ground motion data from the 1989 Loma Prieta and 1994 Northridge earthquakes. Period-dependent and intensity-dependent spectral acceleration amplification factors for different site conditions are presented. The proposed scheme results in a significant reduction in standard error when compared with a simpler “rock vs. soil” classification system. Moreover, results show that sites previously grouped as “rock” should be subdivided as competent rock sites and weathered soft rock/shallow stiff soil sites to reduce uncertainty in defining site-dependent ground motions. Results also show that soil depth is an important parameter in estimating seismic site response. The standard errors resulting from the proposed site classification system are comparable with those obtained using the more elaborate code-based average shear-wave velocity classification system.
Empirical Models for Site- and Region-Dependent Ground-Motion Parameters in the Taipei Area: A Unified Approach
Authors: Sokolov Vladimir Yu , Loh Chin-Hsiung , Wen Kuo-Liang
Published: July 2003

We calculated peak ground accelerations and response spectra for the Taipei area using stochastic simulation technique on the basis of recently obtained empirical models. The source, path and site effects were characterized separately on the basis of the analysis of a large collection of ground-motion recordings obtained since 1991 in the Taiwan area. The simple ω-squared Brune's point-source model combined with regional anelastic attenuation ( Q) and duration (τ0.9) models provide a satisfactory estimation of ground-motion parameters for rock sites. Effects of local site response are considered by means of empirical soil/bedrock spectral ratios calculated as ratios between spectra of actual earthquake records and those modeled for hypothetical “hard rock” site. The results of the simulation demonstrate that this combination of source, path and site response models provides an accurate prediction of “site- and region-dependent” ground-motion parameters for the Taipei basin for the broad range of earthquake magnitudes, distances and site conditions. The model, with a set of generic soil profiles, can be considered as an efficient tool for estimating of design input ground motion parameters in the Taipei basin both in deterministic (scenario earthquakes) and probabilistic (“site- and region-dependent” Uniform Hazard response spectra) seismic hazard assessment.
Architectural Expression of Seismic Strengthening
Authors: Charleson Andrew , Preston Julieanna , Taylor Mark
Published: July 2003

Current seismic strengthening approaches to historic buildings place emphasis upon concealing engineering technologies. This study investigates, through a process of architectural and structural engineering design, the architectural possibilities inherent in a completely different approach. Recognizing both conservation concerns and the architectural qualities of two existing earthquake-prone buildings, the study explores seismic strengthening strategies that are exposed to view in order to contribute, in both a physical and aesthetic sense, a layer of architectural richness. A 1960s eight-story reinforced-concrete office building and a three-story unreinforced masonry building are the subject of theoretical seismic strengthening schemes. The paper describes the buildings, the strengthening approaches from both architectural and structural engineering perspectives, and comments on the outcome with respect to conservation guidelines. Although the proposed schemes challenge some sections of the guidelines, the authors believe the exposed structure enhances the existing architecture, and in so doing suggests an alternative approach for seismic retrofitting.
Ductility and Deformability of Coupling Beams in Reinforced Concrete Coupled Walls
Authors: Harries Kent A.
Published: July 2003

The seismic response of coupled wall structures is discussed. It is demonstrated through a review of large-scale experimental investigations of coupling beam behavior and analytic studies of coupled wall behavior that often the coupling beam ductility demand exceeds the expected available ductility. As a result, it is possible that coupled wall structures will not behave as desired in the course of a significant seismic event. Limits to the allowable degree of coupling are proposed as a remedy to this apparent deficiency. Additional design and analysis issues are discussed including reduced section properties and wall overstrength requirements.
Performance-Based Design Approach for Seismic Rehabilitation of Buildings with Displacement-Dependent Dissipators
Authors: Ruiz Sonia E. , Badillo Hiram
Published: July 2003

A performance-based approach for seismic retrofitting of buildings with energy dissipating devices is presented. The approach may be seen as an algorithm useful for converging to a preliminary design of a system to be analyzed according to the time history approach recommended in the NEHRP Guidelines for the Seismic Rehabilitation of Buildings (FEMA 273). The algorithm is based on the analysis of equivalent single-degree-of-freedom models with added parallel elements that represent the dissipating devices. The combined systems are analyzed under sets of accelerograms associated with different return intervals. The acceptance criteria are intended to control the peak drift of the rehabilitated structure and the maximum ductility demand of the dissipating devices. It is required that these maximum structural responses, for a given seismic intensity, be equal to or smaller than those associated with a given probability of exceedance. The approach is successfully applied to a ten-story, three-bay frame rehabilitated with U-shaped steel dissipators.
Dynamic Expression Profile of p21WAF1/CIP1 and Ki-67 Predicts Survival in Rectal Carcinoma Treated With Preoperative Radiochemotherapy
Authors: Rau Beate , Sturm Isrid , Lage Hermann , Berger Stefan , Schneider Ulrike , Hauptmann Steffen , Wust Peter , Riess Hanno , Schlag Peter M. , Dörken Bernd , Daniel Peter T.
Published: July 2003

Purpose: We investigated p53 and its downstream effectors p21WAF1/CIP1, BAX, and hMSH2 as well as the proliferation marker Ki-67 (mki-67/MIB-1) in patients undergoing preoperative radiochemotherapy for rectal carcinoma to identify prognostic and predictive factors. The focus of this study was on the dynamics of these genetic markers in a longitudinal study—that is, before and after radiochemotherapy.

Patients and Methods: Expression of p53, BAX, p21WAF1/CIP1, Ki-67, and hMSH2 was investigated by immunohistochemistry in pre- and posttherapeutic tumor samples in 66 patients. Tumor DNA was screened for p53 mutations by single-strand conformation polymorphism–polymerase chain reaction (SSCP-PCR). Paired tumor samples (pretherapy and posttherapy) were collected prospectively.

Results: Patients with a decrease in p21 expression following radiochemotherapy had better disease-free survival (P = .03). Similarly, patients with an increase in proliferative activity as measured by increased Ki-67 expression posttherapy had better disease-free survival (P < .005). In addition, we observed a significantly better prognosis for patients with high hMSH2 expression. In contrast, pretherapeutic levels of p53, BAX, or p21 expression and p53 mutation had no prognostic value, indicating that the combination of radiotherapy and chemotherapy might override defects in these genes.

Conclusion: These findings are novel and support the clinical relevance of p21 in the suppression of both proliferation and apoptosis. Thus, the dynamic induction of p21WAF1/CIP1 was associated with a lower proliferative activity but an ultimately worse treatment outcome following neoadjuvant radiochemotherapy and tumor resection. Induction of p21, therefore, represents a novel resistance mechanism in rectal cancer undergoing preoperative radiochemotherapy.
Long-Term Cause-Specific Mortality of Patients Treated for Hodgkin’s Disease
Authors: Aleman Berthe M.P. , van den Belt-Dusebout Alexandra W. , Klokman Willem J. , van’t Veer Mars B. , Bartelink Harry , van Leeuwen Flora E.
Published: July 2003

Purpose: To assess long-term cause-specific mortality of young Hodgkin’s disease (HD) patients.

Patients and Methods: The study population consisted of 1,261 patients treated for HD before age 41 between 1965 and 1987. Follow-up was complete until October 2000. For 95% of deaths, the cause was known. Long-term cause-specific mortality was compared with general population rates to assess relative risk (RR) and absolute excess risk (AER) of death.

Results: After a median follow-up of 17.8 years, 534 patients had died (55% of HD). The RR of death from all causes other than HD was 6.8 times that of the general population, and still amounted to 5.1 after more than 30 years. RRs of death resulting from solid tumors (STs) and cardiovascular disease (CVD) were increased overall (RR = 6.6 and 6.3, respectively), but especially in patients treated before age 21 (RR = 14.8 and 13.6, respectively). When these patients grew older, this elevated mortality decreased. The overall AER of death from causes other than HD increased throughout follow-up. Patients receiving salvage chemotherapy had a significantly increased RR of death from STs, compared to patients receiving initial therapy only.

Conclusion: The main cause of death among HD patients was lymphoma, but after 20 years, HD mortality was negligible. The RRs and AERs of death from second primary cancers (SCs) and CVDs continued to increase after 10 years. Even more than 30 years after diagnosis, HD patients experienced elevated risk of death from all causes other than HD. Increased risk of death from SCs and CVDs was found especially in patients treated before age 21, but these risks seemed to abate with age.
Increased Age at Diagnosis Has a Significantly Negative Effect on Outcome in Children With Down Syndrome and Acute Myeloid Leukemia: A Report From the Children’s Cancer Group Study 2891
Authors: Gamis Alan S. , Woods William G. , Alonzo Todd A. , Buxton Allen , Lange Beverly , Barnard Dorothy R. , Gold Stuart , Smith Franklin O.
Published: July 2003

Purpose: To determine the outcome of children with Down syndrome (DS) and acute myeloid leukemia (AML) receiving standard timing chemotherapy without bone marrow transplantation (BMT), with determination of prognostic factors.

Patients and Methods: Children with DS and newly diagnosed AML or myelodysplasia were prospectively enrolled on Children’s Cancer Group study 2891 (N = 161) and treated uniformly with four standard timing induction courses of dexamethasone, cytarabine arabinoside, 6-thioguanine, etoposide, daunorubicin (DCTER) followed by intensively timed high-dose cytarabine.

Results: Children with DS were significantly younger at diagnosis than those without (median age, 1.8 v 7.5 years, respectively; P < .001), with more megakaryocytic leukemia (70% v 6%; P < .001). Higher complete remission rates (91%) were achieved in children with DS than among those without DS (75%; P < .001). Equivalent grade 3 to 4 toxicity (29% v 30%; P = .84) was seen, though children with DS had greater pulmonary toxicity (P < .01) during induction and mucositis during intensification (P = .12). Children with DS had significantly better 8-year event-free survival (EFS; 77% v 21% standard and 40% intensive induction; P < .0001). Multivariate analysis in children with DS revealed that only age at diagnosis of 2 years or older was a risk factor for greater relapse risk (odds ratio, 4.9; P = .006) and worse survival. Children between ages 0 to 2 years (n = 94) had a 6-year EFS of 86%; those from 2 to 4 years (n = 58), 70%; and those older than 4 years (n = 9), 28%. Remission failures were the primary reason for worse 6-year EFSs (1% in those 0 to 2 years v 14% if >2 years; P = .002).

Conclusion: Outcome for children with DS and AML is excellent with standard induction therapy, but declines with increasing age.
Randomized Phase II Comparison of Dose-Intense Gemcitabine: Thirty-Minute Infusion and Fixed Dose Rate Infusion in Patients With Pancreatic Adenocarcinoma
Authors: Tempero Margaret , Plunkett William , Ruiz van Haperen Veronique , Hainsworth John , Hochster Howard , Lenzi Renato , Abbruzzese James
Published: July 2003

Purpose: To conduct a randomized phase II trial of dose-intense gemcitabine using a standard 30-minute infusion or the fixed dose rate (FDR) infusion (10 mg/m2/min) in patients with pancreatic adenocarcinoma.

Patients and Methods: In this prospective trial, patients with locally advanced and metastatic pancreatic adenocarcinoma were treated with 2,200 mg/m2 gemcitabine over 30 minutes (standard arm) or 1,500 mg/m2 gemcitabine over 150 minutes (FDR arm) on days 1, 8, and 15 of every 4-week cycle. The primary end point of this trial was time to treatment failure. Secondary end points included time to progression, median survival, safety, and pharmacokinetic studies of gemcitabine.

Results: Ninety-two patients were enrolled onto this study; 91% of the patients had metastatic disease. Time to treatment failure was comparable in both treatment groups; however, the median survival for all patients was 5.0 months in the standard arm and 8.0 months in the FDR arm (P = .013). For patients with metastases, the median survival was 4.9 months in the standard arm and 7.3 months in FDR arm (P = .094). The 1- and 2-year survival rates for all patients were 9% (standard arm) versus 28.8% (FDR; P = .014) and 2.2% (standard arm) versus 18.3% (FDR; P = .007), respectively. Patients in the FDR infusion arm experienced consistently more hematologic toxicity. Pharmacokinetic analyses demonstrated a two-fold increase in intracellular gemcitabine triphosphate concentration in the FDR arm (P = .046).

Conclusion: Pharmacokinetic and clinical data in this trial supports the continued evaluation of the FDR infusion strategy with gemcitabine.
Neonatal Estrogen Down-Regulates Prostatic Androgen Receptor through a Proteosome-Mediated Protein Degradation Pathway
Authors: Woodham Carl , Birch Lynn , Prins Gail S.
Published: July 2003

Brief exposure of male rats to estrogens during the neonatal period interrupts normal prostate development, alters epithelial cell differentiation, and predisposes this gland to hyperplasia and severe dysplasia analogous to prostatic intraepithelial neoplasia (PIN) with aging. Previous work demonstrated that the reduced growth, secretory activity, and androgen sensitivity that are observed in the adult ventral lobe are a function of reduced androgen receptor (AR) levels. Down-regulation of AR protein was found to occur immediately following neonatal exposure to estradiol benzoate (EB) and persist through adulthood and aging, indicating a permanent imprint on the ability of the prostate to express normal AR levels. To determine the intracellular mechanism of AR down-regulation by estrogens, the present study examined the effect of neonatal EB on AR gene transcription, mRNA levels, protein translation, and protein degradation in the d 10 ventral prostate glands. Nuclear run-on assays showed no alteration in AR gene transcription following exposure to EB on d 1–5 compared with controls. In situ hybridization and quantitative (q) RT-PCR revealed no difference in mRNA levels in the stromal or epithelial cells in response to estrogen exposure which, taken together, indicate that estrogen down-regulation of AR is mediated at the posttranscriptional level. AR translation was assessed with an in vitro transcription-translation assay in the presence of prostatic lysates from oil and estrogen-exposed animals, and no treatment effect was noted. AR degradation was examined in an in vitro assay validated with adult intact and castrate prostates. Prostatic lysates from intact rats initiated AR degradation with a t1/2 of 2.31 h, whereas proteins from castrate rats accelerated AR degradation to a t1/2 of 1.34 h (P < 0.001). Prostatic lysates from control d 10 prostates induced AR degradation with a t1/2 of 1.49 h, whereas estrogenized prostates increased AR degradation to a t1/2 of 1.11 h (P < 0.001). Proteosome inhibitors MG132 and ALLnL were able to reverse AR degradation induced by prostatic lysates from adult intact and castrate rats as well as from developing and estrogenized prostates, indicating that AR degradation was mediated through the proteosome pathway. Furthermore, the proteosome-mediated AR degradation in the estrogenized d 10 prostate was associated with a marked suppression of Akt phosphorylation that has been linked to AR degradation in other systems. Taken together, the present data show that exposure to neonatal estrogens down-regulates AR protein levels in the ventral prostate gland by accelerating AR degradation, which is mediated through the proteosome pathway.
Hypothalamic Melanin-Concentrating Hormone Is Induced by Cold Exposure and Participates in the Control of Energy Expenditure in Rats
Authors: Pereira-da-Silva Márcio , Torsoni Márcio A. , Nourani Hugo V. , Augusto Viviane D. , Souza Cláudio T. , Gasparetti Alessandra L. , Carvalheira José B. , Ventrucci Gislaine , Marcondes Maria Cristina C. G. , Cruz-Neto Ariovaldo P. , Saad Mário J. A. , Boschero Antonio C. , Carneiro Everardo M. , Velloso Lício A.
Published: July 2003

Short-term cold exposure of homeothermic animals leads to higher thermogenesis and food consumption accompanied by weight loss. An analysis of cDNA-macroarray was employed to identify candidate mRNA species that encode proteins involved in thermogenic adaptation to cold. A cDNA-macroarray analysis, confirmed by RT-PCR, immunoblot, and RIA, revealed that the hypothalamic expression of melanin-concentrating hormone (MCH) is enhanced by exposure of rats to cold environment. The blockade of hypothalamic MCH expression by antisense MCH oligonucleotide in cold-exposed rats promoted no changes in feeding behavior and body temperature. However, MCH blockade led to a significant drop in body weight, which was accompanied by decreased liver glycogen, increased relative body fat, increased absolute and relative interscapular brown adipose tissue mass, increased uncoupling protein 1 expression in brown adipose tissue, and increased consumption of lean body mass. Thus, increased hypothalamic MCH expression in rats exposed to cold may participate in the process that allows for efficient use of energy for heat production during thermogenic adaptation to cold.
Overexpressed Pituitary Tumor-Transforming Gene Causes Aneuploidy in Live Human Cells
Authors: Yu Run , Lu Wenge , Chen Jiandong , McCabe Chris J. , Melmed Shlomo
Published: July 2003

The mammalian securin, pituitary tumor-transforming gene (PTTG), is overexpressed in several tumors and transforms cells in vitro and in vivo. To test the hypothesis that PTTG overexpression causes aneuploidy, enhanced green fluorescent protein (EGFP)-tagged PTTG (PTTG-EGFP) was expressed in human H1299 cancer cells (with undetectable endogenous PTTG expression) and mitosis of individual live cells observed. Untransfected cells and cells expressing EGFP alone exhibited appropriate mitosis. PTTG-EGFP markedly prolonged prophase and metaphase, indicating that PTTG blocks progression of mitosis to anaphase. In cells that underwent apparently normal mitosis (35 of 65 cells), PTTG-EGFP was degraded about 1 min before anaphase onset. Cells that failed to degrade PTTG-EGFP exhibited asymmetrical cytokinesis without chromosome segregation (18 of 65 cells) or chromosome decondensation without cytokinesis (9 of 65 cells), resulting in appearance of a macronucleus. Fifty-one of 55 cells expressing a nondegradable mutant PTTG exhibited asymmetrical cytokinesis without chromosome segregation, and some (4 of 55) decondensed chromosomes, both resulting in macronuclear formation. During this abnormal cytokinesis, all chromosomes and spindles and both centrosomes moved to one daughter cell, suggesting potential chaos in the subsequent mitosis. In conclusion, failure of PTTG degradation or enhanced PTTG accumulation, as a consequence of overexpression, inhibits mitosis progression and chromosome segregation but does not directly affect cytokinesis, resulting in aneuploidy. These results demonstrate that PTTG induces aneuploidy in single, live, human cancer cells.