Confidence Factor?

Eurocode 8 Part 3 (EC8-3) is devoted to assessment and retrofitting of existing buildings. In order to take into account the uncertainty in the knowledge of structural properties, EC8-3 defines, analogously to the ordinary material partial factors, an adjustment factor, called “confidence factor (CF),” whose value depends on the level of knowledge (KL) of properties such as geometry, reinforcement layout and detailing, and materials. This solution is plausible from a logical point of view but it cannot yet profit from the experience of its use in practice, hence it needs to be substantiated by a higher level probabilistic analysis accounting for and propagating epistemic uncertainty (i.e., incomplete knowledge of a structure) throughout the seismic assessment procedure. This article investigates the soundness of the format proposed in EC8-3. The approach taken rests on the simulation of the entire assessment procedure and the evaluation of the distribution of the assessment results (distance from the limit state of interest) conditional on the acquired knowledge. Based on this distribution, a criterion is employed to calibrate the CF values. The obtained values are then critically examined and compared with code-specified ones. The results pinpoint a number of deficiencies that appear to somewhat invalidate the approach. The methodological significance of the work extends beyond the assessment procedure in EC8-3, since similar factors appear in other international guidelines (e.g., the knowledge factor of FEMA356).     

EUROCODE 8 DESIGN RESPONSE SPECTRA EVALUATION USING THE K-NET JAPANESE DATABASE

The Eurocode 8 (EC8) currently proposes two standard shapes for the design response spectra. Type 1 spectra are enriched in long period and are suggested for high seismicity regions. Conversely, Type 2 spectra are proposed for low to moderate seismicity areas (like France), and exhibit both a larger amplification at short period, and a much smaller long period contents, with respect to Type 1 spectra. These propositions, however, were constrained using few events mostly recorded on analogical instruments. In the present study, we use the Japanese high quality digital K-net array in order to evaluate the proposed ECS response spectra. Furthermore, all K-net stations have geotechnical characterisation. We first constructed a database of shallow events, depth less than 25 km, to avoid subduction related records. The database spans six years of seismicity from 1996 until 2003. Thus, 591 events were selected with moment magnitude between 4 and 7.3, recorded at 691 stations, giving a total of 6812 two horizontal components accelerograms. Using these records, we computed spectral ground-motion prediction equations and we used them to review the shape of the proposed EC8 spectra. In particular, we studied the plateau-PGA ratio level, the period interval where this plateau is constant, and site amplification effects. The results show surprisingly that the Type 2 rock better envelope the Japanese data. Another interesting observation is that the K-net data corresponding to all soil classes are rich in short periods around 0.1 s. This characteristic has not been observed in other worldwide databases. Normalised empirical predictions show a widening of the plateau as the soil conditions degrade. This suggests that the Type 2 EC8 spectra do not cover enough the long periods for EC3-soil classes C, D and E. Finally, the computed ground-motion prediction equations show that the peak ground acceleration (PGA) is nearly invariant to the soil conditions. Soil effects are mainly seen in the shape and plateau level.     

Seismic Vulnerability Assessment of an Infilled Reinforced Concrete Frame Structure Designed for Gravity Loads

In the last decades, particular attention has been paid to the seismic vulnerability of existing reinforced concrete buildings designed for gravity loads only. Such buildings, designed before the introduction of capacity design in modern seismic codes, are very common, particularly in seismic prone countries of the Mediterranean area. Due to poor detailing and lacking of capacity design principles, high vulnerability has been highlighted in several past studies. In this article, inadequate seismic response and peculiar damage pattern are investigated by means of shake table tests performed on a 1:2 scaled 3-story infilled prototype. Particular attention is given to the role of beam-column joints and frame-panel interaction. The effectiveness of the EC8-based assessment approach is then evaluated; both linear and nonlinear numerical models, with different levels of sophistication, have been implemented in order to explore their behavioral aspects.     

Nonlinear Static and Dynamic Behavior of a 16-Story Torsionally Sensitive Building Designed According to Eurocodes

A 16-story building under construction in Bucharest has been designed according to the provisions of EC2 and EC8, using elastic spectral modal analysis. Considering that the building is torsionally sensitive in the nonlinear range, it was further checked and verified using nonlinear dynamic and static procedures, using a detailed space-frame model. Specifically, time-history analysis for seven different excitations, as well as respective inelastic static analysis taking into account torsional effects were performed. The results are examined regarding structural (global) and member (local) response and various issues concerning the adequacy of the original elastic design and the applicability of advanced analysis methods are discussed.     

Modeling the Cyclic Flexural and Shear Response of the R. C. Hollow Box Columns of an Existing Viaduct

The cyclic response of R.C. hollow box columns, constructed as part of a typical single-column bent viaduct, built in the 1970’s in Central Europe, was studied both experimentally and analytically. Moderate displacement ductility capacity (between 3 and 4) was observed regardless of the column construction details, which are nowadays considered inappropriate for seismic regions. Standard analytical flexural models correlated with the experimental results quite well. Shear strength was estimated using the two methods included in the EC8 standards, as well as the method developed at the University of California, San Diego. Quite different results were obtained. The most accurate was the third method.     

EXTENSION OF EUROCODE 8 TORSIONAL PROVISIONS TO MULTI-STOREY BUILDINGS

A procedure is presented to extend the static torsional provisions of the Eurocode 8 (EC8) to asymmetrical multi-storey buildings. It is shown that even if the conditions in Annex A of EC8 are satisfied, the static torsional provision will not be effective to compensate for the effect of torsion unless the building possesses a minimum level of torsional stiffness. By means of examples, it is shown that this minimum torsional stiffness condition can be specified in the Code using the mean stiffness radius of gyration of the building calculated based on the proposed procedure as an index.     

The Disposal of European Community Food Surpluses

Since, at its inception, the European Community (EC) was highly dependent on food imports, EC institutions were not designed to facilitate overseas market development for food exports. As time passed, the EC has become much more self-sufficient in food, generating large surpluses in cereals and dairy products. Market development has never been an official EC policy goal, but there is evidence that the EC has used food aid to encourage Third World countries to increase food imports from Europe. Evidence also exists that the Community has used export subsidies as a means of competing for an increased share of promising international markets, though this effort has not been unambiguously successful.     

A Comparison of Two Methods for Recording Entheseal Change on a Post‐Medieval Urban Skeletal Collection from Aalst (Belgium)

This research compares two current methods for recording bony changes at muscle attachment sites, called entheseal changes (EC); the Mariotti method and the Coimbra method, to evaluate the concordance and comparability of results in a post‐medieval skeletal collection from Aalst, Belgium (n = 116). For both methods, the EC scores produce broadly similar patterns, are symmetrical and differ between age groups. Statistical differences between the upper and lower limb and the lower limb of males and females only occur in the Mariotti method. With careful consideration of the influence of different EC score ranges, the results from the two methods can generally be compared.     

面向文物保护的3S技术及其集成应用

系统地介绍了信息时代的高新技术-3S技术及其当前进展,分析了其在物保护领域应用的适用性,通过工程实例描述了3S技术及其集成应用的具体实践过程与优越性,展示了其在物保护领域的应用前景。     

NON-LINEAR SEISMIC RESPONSE OF ECS DESIGNED RC BUILDING STRUCTURES

In this paper, results of an analytical study on the non-linear dynamic behaviour of reinforced concrete buildings designed according to modern European Codes (Eurocode 8) are presented. An investigation of the seismic performance of 8-storey regular and irregular buildings is carried out. The study is aimed at evaluating their seismic structural performance with a focus on the influence of several design parameters used in the code affecting non-linear response. Towards this aim, use is made of a suite of spectrum-compatible artificial accelerograms. It is concluded that EC8 provisions, although correct in principle, are conservative, at least for the structures and input motions considered, in view of the very low predicted damage levels observed in most cases.     

The implementation of EG regional programmes in Greece: A critical review

The effectiveness of the implementation process in EC regional programmes has been subject to more attention in recent years. In the meantime, some inhibiting factors that influence the level of success and failure of the implementation of regional programmes have been revealed, while others are still being researched. The obstacles in implementing the Integrated Mediterranean Programme of Eastern Central Greece (IMP‐ECG) were found to include a widespread lack of know‐how in the integrated planning techniques which had to be applied, the dominance of a traditional centrist administrative apparatus, the inadequate supervision and monitoring of the programmes and, lastly, the invincible power of clientelism with its adverse effects on the intended objectives of the programme. Unquestionably the experience of the IMP‐ECG can justifiably be used as a lesson to improve the quality of implementation of current and forthcoming EC regional programmes.     

Major Systems of Thematic Resonance in the Iliad

It has been suggested (Heiden 1996) that in the Iliad thematically analogous "Achilles-decision" books (books 1, 9, and 16) and thematically analogous "Zeus-decision" books (books 8, 15, and 24) are arranged in analogous positions at the beginnings and ends of three "movements" (1-8, 9-15, 16-24 = A₁-Z₁, A₂-Z₂, A₃-Z₃). This observation provides the key to a comprehensive system that relates many distant segments of the Iliad. The parallel relationship of thematically resonant beginnings and ends extends to the interior segments of the "movements". Moreover, each movement displays an internal arrangement based on symmetrical ring composition. These two systems are coordinated. They might have served to cue audience recall and comparison of distant thematically resonant segments.     

Solar flux and seasonal variations of the mesopause temperatures at 51°N

Observations of the OH (8-3) band airglow emission, using a multichannel tilting filter type photometer, have been carried out at Calgary (51°N, 114°W), Canada, since 1981. In this paper recent measurements of the nocturnal, seasonal and solar flux variations of the mesopause temperature, obtained from the rotational temperature of the OH (8-3) band observations, are presented. The data presented span the ascending phase of the present solar cycle viz. 1987–1988 (low solar activity) and 1990 (high solar activity). Good correlations (r = 0.73) between the OH (8-3) band rotational temperature and the 10.7 cm solar flux were observed. The mean temperature for the period investigated was about 210 K. The seasonally averaged nocturnal variations show only small irregular excursions, possibly associated with solar tides and the passage of gravity waves in the mesopause region. However, the observed rotational temperatures show considerable night-to-night changes.     

Information without frontiers: Financial services,EC regulation and European cities

Using Castells' notion of the informational mode of development, this briefing investigates the changing hierarchy and function of European cities in the light of EC policies. The EC regulatory regime is identified as an integral part of the informational mode of development, setting the parameters within which the corporate sector operates. It is argued that the purpose of information flows is mainly control. A new constellation of European cities is anticipated which depends to a large extent upon the degree to which cities, competing against one another, are able to establish central urban complexes. These are based on the agglomeration economies between corporate headquarters, financial institutions and producer services at the urban level, and information flows at a global level of communications. Among the vast array of EC policies the paper identifies those in support of innovation and telecommunications, the deregulation of financial services, and regional policy as crucial for urban development. Given the requirements of infrastructure, institutions, professional skills and regulatory competence, existing metropolitan centres will capitalize on their comparative advantage and attempt to build on these in the future. These developments are likely to foster further concentration of capital and investment in a few major centres, thus counteracting other EC policies of regional equalization and harmonization. It is argued that these and other contradictions are an amplification of those already afflicting the capitalist state at both national and local levels. The paper also offers an opportunity to reassess aspects of traditional location theory, in particular central place models, in the light of these developments and finds them wanting. The same conclusion is reached regarding the cost‐benefit calculus of the Cecchini Report.     

Activity Reconstruction of Post‐Medieval Dutch Rural Villagers from Upper Limb Osteoarthritis and Entheseal Changes

The first objective of this study is to reconstruct levels and types of physical activity and associated sexual and social differences using human skeletal remains from the predominately 19th century Dutch cemetery of Middenbeemster. For most individuals, life in the Beemster centred around dairy farming and was heavily based on manual labor, with a purported higher class of wealthier individuals performing less manual labor. Two skeletal markers of activity are examined in the upper limb of late young adult and middle‐aged adults of both sexes (26–49 years, n = 69): osteoarthritis (OA) and entheseal changes (EC). Results support the hypothesis that the majority of the population engaged in high levels of physical activity; however, a group with a clearly lower or different pattern of activity, possibly representing a higher, less active class, was not discernible. This may be due to a low number of less active individuals in the analysed sample and/or the heterogeneity of occupations and activities. A gendered division of labour was evident in the EC data with males having more pronounced muscle attachments in almost all sites, especially the biceps brachii, used primarily in lifting. Females had more pronounced triceps brachii, which may be due to activities that required pushing or pulling with the elbow in a flexed position. The prevalence and severity of OA did not differ between the sexes. While this could be interpreted to indicate men and women engaged in a similar level of strenuous activity, hormonal and anatomical differences limit the strength of the comparison. The second objective of this study is to evaluate the concordance of OA and EC as activity markers. The correlation between OA and EC is very low, illustrating their variable and complex etiologies. Etiological factors need further research for OA and EC to become more reliable activity markers. Copyright © 2014 John Wiley & Sons, Ltd.     

3D reality-based artefact models for the management of archaeological sites using 3D Gis: a framework starting from the case study of the Pompeii Archaeological area

This work describes the procedures, the different techniques and the pipeline used for creating a digital framework that should assist the Superintendence of Pompeii in the digital reconstruction, classification, management and visualisation of archaeological finds inside an advanced 3D web-based repository of reality-based data. Specific topics have been focused on the quality assessment procedures adopted to ensure consistency and reliability of data throughout the whole 3D models acquisition and pipeline creation, as well as on the particular semantic reality-based structure adopted to develop an information system into a knowledge one. The main purposes of our framework have been the usage of 3D digital models as a restitution of the real object and as a metaphor for navigating through the data; 3D models were used as archaeological cognitive systems and developed as a collection of structured objects, identified through a precise terminology that allows to easily extend the concept of 2D GIS to 3D GIS. In addition, the system was developed as a scalable application that allows the use of the same database by different users, simply filtering the data according to the specific requirements, and can operate both as standalone and web-based application.     

Multi-Component Seismic Response Analysis – A Critical Review

Issues related to multi-components seismic response analysis are critically reviewed and their implications with respect to the current codified approaches are studied. The issues specifically addressed are: (1) the directions of earthquake forces to excite a structure when the direction of the potential epicenter is known; (2) different commonly used combination rules to obtain the critical response when responses are available in different directions; and (3) the applicability of the combination rules for elastic and inelastic analyses. Based on an extensive parametric study consisting of three-dimensional 1-, 3-, 8-, and 15- story buildings made of moment-resisting steel frames and 20 recorded earthquakes, it is observed that the principal components produce larger responses than the normal components. The 30% and SSRS rules generally underestimate the axial loads in columns. The 30% combination rule is slightly better than the SSRS rule. For both rules, the uncertainty in the estimation of the axial loads in terms of COV is very large (about 25%). The statistics obtained for axial loads and total base shear indicate that the combination rules are applicable for both elastic and inelastic cases. The critical response could be obtained for an orientation different from that of the principal components. The differences are found to be slightly greater for the scaled earthquakes producing a considerable inelastic behavior. Considering the enormous amount of efforts needed to address the directionality effect, it is believed that the responses obtained by the principal components will be acceptable in most cases; however, for critical structures the components should be rotated to obtain the critical responses.     

Studying Pleistocene Neanderthal and cave hyena Dietary Habits: Combining Isotopic and Archaeozoological Analyses

Stable isotope analysis is increasingly used to gain insight in the configuration of Pleistocene ecosystems. The application of isotope analysis to Neanderthal and cave hyena bone assemblages has led to hypotheses about the niche differentiation between these species. Comparing isotopic data with archaeozoology analyses shows discrepancies between the results of both analytical methods. Here, the results of all northwest European stable isotope studies on Neanderthals are reviewed. The emphasis of the analysis is on a sample of sites from MIS 4-3 in southwest France. Causes of the discrepancy between archaeozoological and stable isotope results are discussed and hypotheses reconciling the data are proposed. Recommendations for further research will allow testing of the hypotheses and increase our understanding of the functioning of Pleistocene ecosystems.