Cost-Benefit Analysis of Alternative Retrofit Strategies for RC Frame Buildings

Monetary losses induced by earthquakes in Reinforced Concrete (RC) buildings are mainly due to damage to non-structural elements (infills, partitions, finishes, etc.). In this study, alternative retrofit strategies for reducing monetary losses in RC frame buildings are examined. They include local strengthening of infills (and partitions) and seismic isolation. The Expected Annual Loss (EAL) of a number of RC frame buildings, pre- and post-rehabilitation, is evaluated, following the time-based assessment approach proposed in the FEMA P-58 guidelines. The breakeven time of each retrofit intervention is then computed, considering the initial cost of the intervention and the expected benefit in terms of EAL reduction.     

Critical Issues in Earthquake Scenario Loss Modeling

The assessment of human or economic losses due to single events (scenario) may effectively support decision makers in the development of important risk mitigation actions. The study presented herein sheds light on several problems and limitations in the current practice of scenario loss modeling, such as: the number of simulations required to achieve convergence; epistemic and aleatory uncertainty in the ground motion prediction and vulnerability models; and consideration of the earthquake rupture geometry. These issues are investigated using the Metropolitan Area of Lisbon (Portugal), and it has been observed that distinct assumptions in the loss modeling can lead to considerably different results. The findings of this study are also pertinent for probabilistic seismic risk analyses in which a large number of stochastically generated events are employed to assess probabilistic losses.     

Critical Issues on Probabilistic Earthquake Loss Assessment

Probabilistic loss modeling can be used to develop risk reduction measures, such as the identification of regions more prone to human and economic losses, or to develop financial mechanisms to transfer the earthquake risk from local governments to the private sector. This study addresses several critical issues in probabilistic loss modeling, and provides recommendations depending on the intended final use of the risk results. Modeling issues related to convergence in probabilistic event-based analysis; consideration of epistemic uncertainties within a logic tree; generation of different types of loss exceedance curves; and derivation of risk maps are thoroughly investigated. The Metropolitan Area of Lisbon is used to explore these issues, and it is demonstrated that different assumptions in the loss modeling process can lead to considerably different risk results. Furthermore, the findings and recommendations of this study are also relevant for institutions that promote the assessment of earthquake hazard and risk, such as the Global Earthquake Model Foundation.     

Developing Direct Displacement-Based Procedures for Simplified Loss Assessment in Performance-Based Earthquake Engineering

Various loss assessment methodologies have been proposed and developed over the past decades to provide risk assessment on a regional scale. There is an increasing need, however, to provide engineers with practical tools for building-specific loss assessment. Recently, progress has been made towards probabilistic loss models such as the PEER framework. However, as comprehensive probabilistic methodologies could be too complex for practicing engineers, this article presents a simplified probabilistic loss assessment methodology that builds on a direct displacement-based framework. The methodology is tested via examination of two RC frame buildings and encouragingly shows similar results to the PEER methodology.     

OFFSHORE FINDS FROM THE BRONZE AGE IN NORTH-WESTERN EUROPE: THE SHIPWRECK SCENARIO REVISITED

Summary.   This article challenges received thinking relating to the interpretation of Bronze Age finds from the seabed in the waters of north-western Europe, especially the North Sea and Channel area. Metal objects recovered from the sea are traditionally presumed to be the result of shipwrecks. As such, their interpretation as casual, if unfortunate loss is unquestioned. However, abandoning the shipwreck scenario as a remnant of the 'sacred vs profane' heuristic, it is suggested that offshore finds could provide insight into deliberate Bronze Age maritime practice, rather than misadventure. Certain patterning in the data of offshore finds, including affinities with hoards on terra firma , urges another interpretive framework – that of considering the sea as a place for deposition. This appeared to be the case particularly in regions which experienced an intensity of maritime interaction, such as the Channel area during the later Bronze Age. From this it is hypothesized that rather than being considered outside the Bronze Age social realm, the sea, especially in the MBA to earlier LBA in the Channel area, was incorporated into Bronze Age cosmology in similar ways to other zones in the landscape.     

Seismic Fragility Curves for Un-Anchored On-Grade Steel Storage Tanks: Bayesian Approach

In this article, Bayesian approach is used for estimation of seismic fragility of un-anchored on‐grade steel storage tanks based on historical data and American Lifeline Alliance tanks database. The approach properly accounts for epistemic as well as aleatory uncertainties. The point and interval estimates of the fragility are formulated based on structural reliability method that implicitly or explicitly reflects the influence of epistemic uncertainty. The fragility curves developed herein are compared to corresponding relations currently available in the technical literature, the comparison suggest that actual tank performance is better than that predicted in the literature. Finally, application of fragilities in loss estimation methodology is investigated and showing a considerable scatter in the results corresponding to different fragilities.     

The prey as patch model: optimal handling of resources with diminishing returns

Foraging theory provides archaeology with a valuable set of tools for investigating the constraints that influenced procurement decisions of the past. The prey-choice model has been used extensively by archaeologists, but has significant limitations given the nature of archaeological data. This paper suggests that the seldom-used Marginal Value Theorem (MVT) is a valuable tool for examining the ecological constraints on foraging decisions and merits further archaeological application. Ethnoarchaeological and experimental cases are presented demonstrating how patch–gains curves can be generated from quantitative data on butchering return rates and handling times. Results indicate that such curves are diminishing return functions. This provides a basis for examining the linkage between processing intensity and resource fluctuation. This model allows archaeologists to address the relationship between attribute-states of faunal remains and predicted optimal post-acquisition decisions. The MVT is valuable to ethnoarchaeology because it identifies how mean foraging return rate influences the handling of acquired prey and makes quantified predictions of return rate based on processing intensity. The MVT can also be applied to archaeological studies of foraging behavior and processing intensity as it can be used to estimate the set of environmental constraints in which a given kill was made (e.g., “good” vs. “bad” times). This approach may also identify the degree to which certain currencies, such as fat, are optimized at the expense of others, such as total caloric intake.     

An Applied Method for General Regional Seismic Loss Assessment—With A Case Study in Los Angeles County

We describe the formulation and application of an integrated general regional seismic loss assessment (RSLA) method for buildings in seismic regions. An efficient method for RSLA is valuable for engineers involved in city planning, risk management, and insurance dealings. In contrast to previously reported methods, the framework presented herein is hazard-based and utilizes a regional rapid seismic hazard deaggregation tool that allows regional assessment to be conducted more efficiently. The proposed technique is implemented as an example to assess general regional seismic loss in Los Angeles County for a ground motion hazard with 10% probability of exceedance in 50 years.     

Using Actor-Network Theory to Characterize the Production of Ancient Maya Caching Events at Cerro Maya (Cerros,Belize)

Inspired by actor-network theory, this research uses an operationalized archaeological actor-network approach to characterize and examine human-object relationships associated with ritual caching deposits (votive bundles of objects) at the site of Cerro Maya (formerly Cerros), Belize. Designed to be broadly applicable for archaeological studies, our archaeological actor-network approach made it possible to inductively examine, characterize, and diachronically compare the complex arrays of human and nonhuman relationships. In contrast to previous studies that characterized caches mainly in symbolic terms, we treated caches as traces of the small-scale actor-networks that emerged during the production of ancient Maya caching events. More specifically, our actor-network methodology made it possible to characterize caches and caching events in terms of the relationships between materials, temporality, objects, places, and groups of people, their intentions, and actions. The inductive and diachronic focus of approach also allowed us to compare arrays of caching actor-networks over time while considering the social affect that caching events had on subsequent caching events and the site’s social development. This approach demonstrates that even simple artifact clusters can be viewed as proxies for highly complex networks of interlinked social relations that play roles in shaping important historical interactions and social orders over time.

     

区域经济联系测度方法述评

区域研究是地理学的核心之一。区域经济联系测度是区域研究的焦点。在系统总结区域经济联系测度的理论与方法的基础上,本文认为区域经济联系测度一般依循尺度确定-区域划分-区域联系测度的路径;测度区域经济联系的主要指标有可达性、经济影响范围、经济联系强度、经济隶属度等。城市在区域网络中的作用、位置是区域经济联系测度的重点。通过区域经济联系强度的测度,有助于区域和城市发展定位,并指导规划。近年来城市化、信息化、全球化的快速发展对区域经济联系的测度提出了新的挑战,需要综合不同的方法或发展新方法来应对。     

TUNING OF SEISMIC HAZARD ESTIMATES BY MEANS OF OBSERVED SITE INTENSITIES

Probabilistic seismic hazard is usually assessed by means of computer codes using seis-mogenic sources, parametric catalogues, seismicity rates and attenuation relationships. All these ingredients are conditioned by expert judgement that influences the final results. Even the attenuation relationships, though strictly based on experimental data, are considered a weak point due to the difficulty of modelling the interaction between seismic energy radiation and site response, and because earthquakes do not usually repeat themselves according to one theoretical model. Recently, methods making wide use of site intensity data have been developed in regions such as Italy, where the observed seismic history at selected sites is quite exhaustive. We analyzed these observations to assess seismic hazard at about 600 sites. We used a probabilistic counting technique, integrating the observations (when necessary), with computed shakings obtained from a logistic-type attenuation model. The results were then compared with the estimates provided by the recent seismic hazard map of Italy, compiled according to the traditional probabilistic seismic hazard approach. The match shows significant differences for some sites. A tentative explanation which seems to point to three alternatives is provided: (1) The mismatch between the two methodologies might appear because the stationary assumption has a poor fit with reality (at least in certain areas); (2) Some sites show a response that is systematically different from the average values predicted using attenuation relationships; (3) The definition of seismogenic zones leads to a bias in the seismicity rate estimate.     

Development of Probabilistic Framework for Performance-Based Seismic Assessment of Structures Considering Residual Deformations

Recently, the importance of considering residual (permanent) deformations in the performance assessment of structures has been recognized. Advanced structural systems with re-centering properties as those based on unbonded post-tensioning tendons are capable of controlling or completely eliminating residual deformations. However, for more traditional systems, which count for the vast majority of buildings, residual deformations are currently considered an unavoidable result of structural inelastic response under severe seismic shaking.

In this article, a probabilistic framework for a performance-based seismic assessment of structures considering residual deformations is proposed. The development of a probabilistic formulation of a combined three-dimensional performance matrix, where maximum and residual deformations are combined to define the performance level corresponding to various damage states for a given seismic intensity levels, is first presented. Combined fragility curves expressing the probability of exceedence of performance levels defined by pairs of maximum-residual deformations are then derived using bivariate probability distributions. The significance of evaluating and accounting for residual deformations within a Performance-based Earthquake Engineering (PBEE) approach is further confirmed via numerical examples on the response of Single Degree of Freedom (SDOF) systems, with different hysteretic behavior, under a selected suite of earthquake records. Joined fragility curves corresponding to various performance levels, defined as a combination of maximum and residual response parameters, are derived while investigating the effects of hysteretic systems and strength ratios. It is observed that stiffness degrading Takeda systems result in lower residual deformations than elasto-plastic systems and show lower probability of exceeding a jointed maximum-residual performance level. For a chosen performance level, Takeda systems with higher strength ratios show better performance, particularly with lower intensity of excitations.     

New Indices for the Existing City-Centers Streets Network Reliability and Availability Assessment in Earthquake Emergency

During earthquake emergencies in existing city-centers, streets network permits inhabitants to reach safe areas, and rescuers to access damaged zones and help population. However, the network can suffer from blocks due to debris of collapsed or heavily damaged buildings. Understanding urban fabric modifications and classifying elements vulnerability are fundamental steps while dealing with risk-assessment and risk-reduction strategies. This article offers a first quick approach for assessing seismic vulnerability of paths network by considering interferences with building heritage damages. Quick data about existing urban fabric (e.g., buildings typology; streets and buildings geometries) are combined for developing new vulnerability indices for streets network. The earthquake macroseismic intensity is introduced for evaluating probable street blockages and summarizing the overall rating of risks in critical network locations, thus intensity that is not included in other current quick methods for streets-building interference is here taken into account. Risk-reduction strategies based on the proposed indices could minimize the interventions on architectural heritage, maximizing the safety of evacuees. These new indices could be combined with traditional assessment of buildings vulnerability, and evaluations on pedestrians’ and vehicles evacuation flows, for evaluating management strategies.     

Conflict,Order, Harmony: The Modern Meaning of the Confucian Tradition

An examination of how a focus on the reading of traditional Confucian texts as a spiritual exercise can enable us to deal productively with modern understandings of the divergences among different ideals of human excellence.An investigation of such ideals has often focused on virtue discourse,but that discourse generates understandable suspicions in many people.A productive approach to these suspicions is to examine both the idea that new virtues (such as spiritual regret) are needed,and the notion that three distinctive modern emphases must play a central role in any contemporary consideration of the relationships among diverse ideals.After considering two kinds of principled opposition to this approach,we turn to Walter Benjamin's exemplary account of the huge gulf between modern and traditional understandings,and the possible aid some texts may offer in bridging it.Focusing on the distinctive operation of specific forms of presentation in the Confucian tradition,we conclude by investigating the idea that reading Confucian texts can be seen even today as an illuminating kind of spiritual exercise.     

A Two‐Tiered Method for Identifying Trends in Media Framing of Policy Issues: The Case of the War on Terror

Research on media framing of policy issues has flourished. Yet the varied approaches to conceptualizing and operationalizing issue frames that make this literature rich also hinder its advancement. Here, we document the benefits of a two‐tiered method: the first level accounts for issue‐specific frames, while the second level tracks frames that generalize across issues. For this study, we draw on generalizable frames from prospect theory (loss vs. gain frames) and social identity theory (self‐referential vs. other‐referential frames). We discuss the theoretical merits of a two‐tiered approach, arguing that it should yield compound insights greater than the sum of its parts. Applying this method to newspaper coverage of the war on terror, we find a strong trend at the generalizable level: media framing of the war shifted over time from a predominant use of “fear” (self‐referential loss) frames to an increasing use of “charity” (other‐referential gain) frames. Our approach further reveals that the fear frames used in the lead‐up to the Iraq War were not driven by issue‐specific frames related to terrorism or weapons of mass destruction as we might have thought, but rather by frames related to the anticipated threats to U.S. troops. This study sharpens our understanding of how framing of the war evolved, but more broadly it suggests that a two‐tiered approach could be applied both within and across policy issues to advance our understanding of the framing process.     

THE PUZZLE OF JOB SEARCH AND HOUSING TENURE: A RECONCILIATION OF THEORY AND EMPIRICAL EVIDENCE

Oswald's thesis posits that homeowners should have longer unemployment spells than renters due to restricted mobility, but repeatedly the reverse is found. I contribute to solve this puzzle analyzing both job search intensity and unemployment duration. First, I show that homeowner's mobility constraints have a negative impact on search. Theoretically, it is shown in a search model with moving costs. Using U.K. Labour Force Survey (LFS) data, it is confirmed when considering outright owners, while leveraged owners have the highest search. Second, I find evidence that homeowners select search methods associated with shorter unemployment spells, suggesting that they search more efficiently.     

Seismic Vulnerability of Building Contents for a Given Occupancy Due to Multiple Failure Modes

A methodology is presented for assessing the seismic vulnerability of inventories of contents to multiple failure modes. An ordering method to find out probabilities of failure of a conditional mode upon the survival of the other modes is applied. The procedure considers the statistical correlation of failure modes due to the dynamic response, such as sliding and/or overturning, of contents and also to non structural components. This methodology was applied to inventories of four types of occupancy (house, school, office, and hospital) located in Mexico City, considering that all contents are situated at ground level. Expected damage functions for these inventories show large differences between them, the house and school inventories being the least vulnerable, and the hospital inventory, the most vulnerable, even for low intensities.     

Design and Assessment Spectra for Retrofitting of RC Buildings

This article presents a novel approach for deriving Retrofit Design Spectra (RDS) that are intended for use in preliminary development and assessment of seismic upgrading scenarios of existing structures. The new spectral representation relates the characteristics of the intervention method chosen as the core of the upgrading strategy, with the ductility and strength demand of the retrofitted structure. The methodology utilized for the derivation of the RDS is based on the Capacity Spectrum Method where the capacity curve is described by relationships for global and local intervention methods that are parameterized in terms of fundamental response quantities. The proposed spectra provide direct insight into the complex interrelation between the characteristics of the intervention method and the implications of the upgrading scenario on demand. Alternative retrofit solutions are thus assessed in an efficient way. A case study is used to illustrate practical application of the new approach.     

Can Earthquake Loss Models be Validated Using Field Observations?

The occurrence of a damaging earthquake provides an opportunity to compare observed and estimated damage, provided that detailed observations of the earthquake effects are made in the field. A question that arises is whether such comparisons can provide the basis for validation of an earthquake loss model. In order to explore this issue, a case study loss model for the northern Marmara region has been set up and the losses have been calculated for various ground-motion fields that arise when different assumptions are made about the ground-motion variability. In particular, the influence of removing the inter-event variability for a scenario earthquake and modeling spatial correlation among ground motions is studied. Further analyses are conducted assuming that a number of accelerograms are available within the region and that knowledge of spatial correlations among ground motions can therefore be used to better predict the motions at sites in the vicinity of the recording stations. The results demonstrate that unless one has a dense network of accelerographs (commensurate with the geographical resolution of exposure), then the variability in the losses cannot be sufficiently reduced to allow validation of the loss model.     

Between Islam and the nation; nation-building,the ulama and Alevi identity in Turkey

This article analyses the relationship between Islam and nationalism by considering the role of the ulama in Turkey, housed within the Presidency of Religious Affairs (PRA). The ulama – religious scholars and experts of Islamic law – in Muslim majority contexts are typically closely linked with the state and play a key role in shaping the boundaries of Islam and of what is Islamically acceptable. However, this is also of consequence for the boundaries of the nation, since in Turkey Islam and nationalism has been intertwined, with Islam playing a central role in nation-building, as a basis of ethnic identity formation and a source of symbols and myths. This articles shows, firstly, that the PRA has acted as a carrier and preserver of Sunni (Hanefi) Muslim identity in continuity with the Ottoman ulama and, secondly, that it has delimited nation-building, by considering its approach to and interventions against Alevi identity.