A Fully Graphical Approach for Limit State Analysis of Existing Structures: Application to Plane Elastic-Plastic Bended Structures and to Plane Masonry Arches

ABSTRACT

When classical elastic analysis fails to model correctly the structural behavior of historical masonry structures because of the brittle, rigid, anisotropic, and inhomogeneous characteristics of their building material, equilibrium-based limit state analysis constitutes an efficient alternative for their structural assessment. The lack of knowledge about the history of loading makes the actual state of stresses impossible to determine for these statically indeterminate structures. However, Plastic Theory provides a powerful theoretical framework that defines in a rather simple way the structural safety level. The lower-bound theorem of plasticity can be applied using graphic statics because it ensures that equilibrium and yield conditions are respected when applying specific constraints to the nodes of the reciprocal diagrams.

This article focuses on limit stat analysis of statically indeterminate structures by means of geometrical considerations using graphic statics reciprocal diagrams. For linear-bended structures, we show that: (1) the conditions of stability can be defined graphically by constructing safety domains; (2) collapse modes can be identified and related to specific reciprocal polygons; and (3) the exact value of the collapse load factor can be deduced graphically from the diagrams. Finally, we extend these results to plane masonry arches in relation with the classical thrust line approach.     

The zooarchaeology of exclusion and expropriation: Looking up from the lower city in Late Bronze Age Hazor

The collapse of complex societies is a recurring theme in archaeological and historical scholarship. Zooarchaeological investigation, conventionally applied in recent studies to detect environmental degradation resulting in resource stress, is employed here to study the social conditions leading to the decline of the powerful Bronze Age city of Hazor, located in the northern Jordan Valley, Israel. The results of the analysis of faunal remains from the lower city show that the exclusion of its residents from ideological use of animals and their impoverishment by elite livestock expropriation preceded other material manifestations of sociopolitical decline in the city. The results are encouraging in respect to the prospective value of zooarchaeology for investigating collapse not directly caused by subsistence failures.     

Ascertaining an agent: using tooth pit data to determine the carnivore/s responsible for predation in cases of suspected big cat kills in an upland area of Britain

The identification of the involvement of a particular carnivore in the modification of bone assemblages concerns a number of fields of research including archaeological and palaeontological enquiry. Taphonomy provides a methodology by which bone assemblages can be analysed and interpreted and this is more often undertaken with archaeological or palaeontological assemblages. A taphonomic analysis is undertaken here in order to determine the perpetrator of predation attacks on domestic stock from a modern-day setting. Recently reported techniques using tooth marks preserved on bone surfaces made by known carnivores are successful at determining some class sizes of predators and are used here to determine the perpetrator(s). Although a class size of carnivore is readily identified by this methodology, a particular carnivore taxon is not. Tooth morphology and dental configuration are reported here as better criteria for identifying a particular taphonomic agent. Tooth pit dimensions are used here to identify the class size of carnivores involved, and tooth morphology and cusp spacing to suggest a medium sized felid and fox as taphonomic agents. The identification of the medium-sized felid may support observations and reports of alleged “big” cat kills in the area. The study has important implications for the interpretation of fossil sites where felids may have been involved in the modification of animal carcasses but are archaeologically invisible in terms of their fossil remains.     

Knowledge Networks as a Regional Development Resource: A Network Analysis of the Interlinks between Scientific Institutions and Regional Firms in the Metropolitan region of Hanover,Germany

The debate on regional innovation potentials has concentrated in recent times upon the topic of regional knowledge networking. This article presents the findings of the first phase of a detailed network analysis of the cooperation relations between scientific institutions and firms in the “metropolitan region Hanover-Brunswick-Göttingen”. The research concentrated on the regional and supra-regional cooperation relations of approximately 500 science establishments of the region, including their interlinks with private sector firms. This analysis of a polycentric metropolitan region's knowledge networks in different fields of competence produced detailed information on the density of knowledge interlinking within the region, on the degree of connectivity between the region's scientific institutions and private sector firms, and on central network nodes within the regional innovation networks. The case study exemplifies the methodical approach of a regional network analysis and emphasizes the role of knowledge networks as a development resource which is of particular relevance to the region's innovation capacities.     

A centralised market orientation: the implicit determinants of Finnish cultural policy in 1990–2010

This article examines the reactions of Finnish cultural policy to the neoliberal turn in its societal environment. The analysis of cultural policy documents in 1990–2010 concentrates on three particular elements of societal change: the reforms in public management, the reorientations in international relations and the paradigm of immaterial production. It is argued here that besides the mythical democratic pluralism of the Nordic welfare states, cultural policy treats newcomers to the political arena selectively. Consequently, the system, constructed originally for protecting free artistic expression and equal distribution of cultural possibilities, has been in the front line of political market orientation in Finland. The orientation is modelled rhetorically after the ideas of cultural pluralism and economic efficiency; in practice, the fight has been a technocratic one between different notions of governmental responsibilities. This mechanism stresses formal procedures at the expense of ad hoc negotiations, leading to a centralised market orientation.     

The red-stained flint crescent from Gesher: new insights into PPNA hafting technology

A red-stained flint crescent found in the Pre-Pottery Neolithic A (ca. 9000 BC) site of Gesher, Israel, provides us with a unique opportunity to study the hafting technology of a particular tool type in the Levant. We present here a reconstruction, based on chemical and mineralogical analyses, of the hafting technologies and materials employed in the process. Use will also be made of relevant studies of the archaeological record. Local material was used for the production of an elastic adhesive paste, mud plaster, which was then hardened to hold the crescent securely in the haft. The study contributes insight into the hafting technology that was most probably implemented in the production and maintenance of composite tools during the Early Neolithic period.     

The Development of “Sports-City” Zones and Their Potential Value as Tourism Resources for Urban Areas

In recent years, several cities have constructed new sports facilities in concentrated areas or supplemented existing facilities to create a themed sport zone. Some have branded these areas as “sports cities” to give them visibility and coherence. This research assesses the rationale for these projects, in particular, their potential value as new tourist areas for cities. Although the relationship between sport and cities is an established part of urban studies, there is currently little research that explicitly addresses this new phenomenon of themed areas of cities dedicated to sport. To address the lack of previous work, existing literature on comparable manifestations of themed urban areas is used as a conceptual basis for the paper. A comparative analysis is then conducted of four specific schemes: “SportCity”, Manchester (UK); “The International Sports Village”, Cardiff (UK); “The Aspire Zone”, Doha (Qatar) and “Dubai Sports City” (UAE). These different sports-city zones are compared and evaluated with reference to issues raised in the literature. The paper concludes that, to be successful, sports-city zones need to be planned as such, and not merely employed as convenient brands for existing events facilities.     

Identification Technique for Soil-Structure Analysis of the Ghirlandina Tower

Historical towers, in particular medieval towers, are an important part of cultural heritage, and their preservation mandates monitoring and detailed analyses of vulnerability under seismic actions as well as of their long-term performance. Certain aspects of structural nature are linked to the masonry behavior as a unilateral material, and other are aspects related to the interaction with soft soil conditions. This study aims to contribute to the aspects of preservation by exploring the role of the soil-structure interaction in predicting the behavior of the structures, with specific reference to the well-documented case history of the medieval Ghirlandina Tower (Modena, Italy). A significant contribution comes from an experimental identification analysis, performed in the presence of ambient vibration. A novel finding is that the soil structure interaction cannot be neglected, in contrast to most published identification analyses that usually assume the structure to have rigid constraint at base.     

Asynchronous,Iterative, and Parallel Procedures for Solving the Weighted-Region Least Cost Path Problem

A family of local, asynchronous, iterative, and parallel procedures (LAIPPs) are described. These procedures are designed to find least cost paths (LCPs) in bounded regions of the plane that have been partitioned into triangular subregions. The unit cost of traversing a given subregion is uniform within the subregion, but varies between subregions. In the case of one-dimensional chains of triangles, the procedures are guaranteed to converge to a global LCP. Although the procedures are guaranteed to terminate, we have so far been unable to prove, in the general case of a two-dimensional triangulation, that the procedures always terminate in admissible paths. Extensive experimental investigations, however, have revealed convergence to admissible paths in all cases examined. While counterexamples are constructed to prove that the procedures may converge to the local rather than global LCPs, convergence to the global LCP was found to occur in nearly all of our experimental investigations. The computational complexity of the procedures, as measured by the number of iterations required for convergence, was found experimentally to be independent of the size of the domain in which the paths lay, and to be slightly greater than linear in the Euclidian length of the paths. The complexity was also found to depend on the cost structure of the domain. Such LAIPPs appear to be promising procedures for both application and further investigation. In particular, the question of convergence is an interesting problem.     

The role of the stress regime on microseismicity induced by overpressure and cooling in geologic carbon storage

Fluid injection in deep geological formations usually induces microseismicity. In particular, industrial‐scale injection of CO₂ may induce a large number of microseismic events. Since CO₂ is likely to reach the storage formation at a lower temperature than that corresponding to the geothermal gradient, both overpressure and cooling decrease the effective stresses and may induce microseismicity. Here, we investigate the effect of the stress regime on the effective stress evolution and fracture stability when injecting cold CO₂ through a horizontal well in a deep saline formation. Simulation results show that when only overpressure occurs, the vertical total stress remains practically constant, but the horizontal total stresses increase proportionally to overpressure. These hydro‐mechanical stress changes result in a slight improvement in fracture stability in normal faulting stress regimes because the decrease in deviatoric stress offsets the decrease in effective stresses produced by overpressure. However, fracture stability significantly decreases in reverse faulting stress regimes because the size of the Mohr circle increases in addition to being displaced towards failure conditions. Fracture stability also decreases in strike slip stress regimes because the Mohr circle maintains its size and is shifted towards the yield surface a magnitude equal to overpressure minus the increase in the horizontal total stresses. Additionally, cooling induces a thermal stress reduction in all directions, but larger in the out‐of‐plane direction. This stress anisotropy causes, apart from a displacement of the Mohr circle towards the yield surface, an increase in the size of the Mohr circle. These two effects decrease fracture stability, resulting in the strike slip being the least stable stress regime when cooling occurs, followed by the reverse faulting and the normal faulting stress regimes. Thus, characterizing the stress state is crucial to determine the maximum sustainable injection pressure and maximum temperature drop to safely inject CO₂.     

Transgenerational Impact of Structural Violence: Epigenetics and the Legacy of Anthracite Coal

This project connects past forms of structural violence to current health conditions found in communities. Using historical and archaeological material from deindustrializing region in the United States, it appears that nutritional and livelihood stress in the late nineteenth century may have resulted in the transgenerational inheritance of negative human health outcomes experienced by descendants today. While more in-depth genetic research is needed, it is clear that the study of health disparities found today may be situated in the long-term stresses (environmental and nutritional) that communities faced generations ago. Historical archaeology is a way to develop a longitudinal study of health disparities.     

一件清代髹漆贴金木雕观音菩萨坐像的保护研究和修复

髹漆贴金木雕属岭南地区代表性的传统木雕工艺,此类文物藏品也因此而独具特色。由于一件清代髹漆贴金木雕观音菩萨坐像存在糟朽、开裂、漆皮起翘、脱落等病害,需采取相应的修复措施。为此,在采集漆层、木胎等样品进行X射线荧光能谱、拉曼、红外光谱、切片观察等分析检测的基础上,依据分析检测结果和木雕保存现状制定实施了表面清理、菌虫防治、裂缝和残缺部位修复补全、脱落漆皮回软回贴、髹漆贴金仿卉处理等技术措施。保护处理后的木雕文物器形完整,色泽协调,形态和性质稳定,达到了预期的效果。上述分析检测手段和保护修复技术对同类文物的保护工作有借鉴作用。     

An interpretation of mosses found in recent archaeological excavations

Recent archaeological excavations at Vindolanda, Northumberland and at York have uncovered considerable quantities of bryophytic material. The mosses are considered here not in terms of their value to the archaeologist as indicators of prevailing environmental conditions but from an ethnological viewpoint. There is strong reason to believe that the mosses at both sites were deliberately harvested in large quantities and employed mainly for their bedding, packing, insulatory and absorbent qualities.     

Evaluating soil resilience in long-term cultivation: a study of pre-Columbian terraces from the Paca Valley, Peru

This study evaluated the soil properties of pre-Hispanic stone-walled terraces by comparing soil quality along terraced catenas in the Paca Valley, a tributary of the Mantaro Valley, Peru. Micromorphological and bulk analyses of terrace soils revealed that despite terracing soil horizonation largely followed the catena. Upland terraced fields had deeper A-horizons with higher biotic activity than uncultivated controls, but less fine material and greater carbonate accumulation. Midslope fields were highly variable in depth and soil properties reflecting considerable substrate and anthropogenic variations in this growing zone. Silts and clay accumulated in valley bottom terraces where pedofeatures indicate an ongoing downhill movement of fine material. The distribution of soil separates down Paca hillsides demonstrates that terraces help moderate, rather than control, the erosion of key soil fractions required for long-term agricultural productivity. This study illustrates how the loss of fine material is partly mitigated by soil consolidation in dense topsoil peds, microaggregates and saprolite. These aggregates are retained by terraces and contribute to deep soil profiles. Nevertheless, many fields show signs of degradation, especially from insufficient organic matter amendment. In addition to farming itself, buried soils and associated artefacts in valley bottom fields indicate mass soil movement, a likely result of disruption caused by Inca road and terrace construction. The poor soil quality of many upland terraces also confirms that stone-walled terraces were constructed on mediocre substrates for farming, indicating a high labour investment for marginal agricultural returns in these areas. Overall, Paca Valley terraces improve topsoil retention and promote deep soil profiles. However, these fields present quite varied growing substrates. It is also apparent that over the last millennium, soil depletion from cultivation has compromised soil quality through loss of fine material and organic matter. Shifts in farming practice away from pre-Hispanic practices such as long-fallow and middening appear to exacerbate this trend.     

Sectarian identity and national identity in the Middle East

This article looks at modern sectarian (here referring to Sunni/Shi'a) identities and their interaction with nationalism in the Middle East. In doing so I make three interrelated claims: 1) the term ‘sectarianism’ is distortive and analytically counterproductive. A better understanding of modern sectarian identity requires us to jettison the term. 2) Once discarded, our focus can then shift to sectarian identity: how it is constructed, perceived, utilized and so forth. A holistic understanding of sectarian identity must recognize the multiple fields upon which it is constructed and contested. The model adopted here frames sectarian identity as simultaneously operating on four fields: doctrinal, subnational, transnational and, crucially for our purposes, the national dimension. 3) Thirdly, this article challenges the assumptions regarding national and sectarian identities in the modern Middle East. Contrary to conventional wisdom, modern sectarian identities are deeply embedded in the prism of the nation‐state and are inextricably linked to nationalism and national identity. The article will rely primarily on the example of modern Iraq but, as will be seen, the Iraqi example is significantly echoed in the cases of Bahrain, Syria and Lebanon.     

Interrogating the uses of culture in the politics of diversity: a case from South Korea

This article seeks to critically examine the ascendancy of culture in the arena of politics by analysing emergent multicultural discourses and policy development in South Korea as an illuminating case study. In exploring various discursive modalities of culture in the politics of diversity, it investigates how culture is identified as a source of social problems and concurrently employed as their solution. Combining discourse analytic and in-depth interviewing techniques, the article focuses on analysing how female marriage migrants and their children are constructed as cultural other, and how the language of culture is deployed to divert attention from issues of power and structural inequalities. In particular, it examines the discourse of ‘cultural deficiency’ and ‘cultural competence’ used in relation to migrants, and assesses the proposed conceptual shift in cultural policy development from multiculture to cultural diversity.     

Structural Assessment of Ancient Masonries before and during a Rehabilitation Process

ABSTRACT

The rehabilitation of old buildings requires detailed knowledge of the mechanical characteristics and stress state of the structural elements, which play an important role in the intervention process. In this sense, non-slightly destructive tests can estimate structural characteristics with good precision at relatively low costs. Consequently, this article presents a device, based on the flat jack technique, applied to continuous stress monitoring over time. It also focuses on the onsite determination of service stresses and its continuous monitoring in several masonry buttresses of a historic building, as well as the assessment of the structural safety before, during, and after an intervention process. A brief analysis of the research is performed, and the motivation and the methodology adopted are described. Finally, the evolution of the measurements recorded and the analysis of the results achieved are detailed. The study enabled recommendations to be made to the intervening agents that guarantee structural safety.