Simulation of Shake Table Tests on Out-of-Plane Masonry Buildings. Part (VI): Discrete Element Approach

ABSTRACT

Although many experimental tests and numerical models are available in the literature, the numerical simulation of the seismic response of existing masonry buildings is still a challenging problem. While the nonlinear behavior of masonry structures is reasonably predictable when the out-of-plane behavior can be considered inhibited, when the in-plane and out-of-plane responses coexist and interact, simplified models seem unable to provide reliable numerical predictions. In this article, taking advantage of the experimental tests carried out in a shaking table on two masonry prototypes at LNEC, a macro-element approach is applied for the numerical simulations of their nonlinear response. The adopted approach allows simulating the nonlinear behavior of masonry structures considering the in-plane and out-of-plane responses. Since it is based on a simple mechanical scheme, explicitly oriented to representing the main failure mechanisms of masonry, its computational cost is greatly reduced with respect to rigorous solutions, namely nonlinear FEM approaches. Two modeling strategies are adopted, namely a regular mesh independent from the real texture of the prototypes and a detailed one coherent with the units disposal. The numerical results are discussed and the correlation between the nonlinear static analyses and the dynamic response is provided.     

Economic Change in the Prehistoric Hexi Corridor (4800–2200 bp), North‐West China

It is widely known that the Hexi Corridor in North‐West China lies at a hub of trans‐Eurasian cultural exchange. Its role became increasingly important during the late prehistoric period, particularly as the ancient Silk Road began to be used. While the profound transformation of local cultural characteristics in the late Neolithic and the Bronze Age is well documented, the detailed economic dynamics of cultural evolution have not yet been clearly illustrated. In this paper, we report on significant new zooarchaeological and faunal isotopic data from the Neolithic and Bronze Age sites in the Hexi Corridor. The primary objective is to systematically reconstruct the prehistoric economic context of this area by combining these new data with previous archaeological studies and radiocarbon dates. We argue that the primary economic activities of local inhabitants changed dramatically in the prehistoric Hexi Corridor. This was marked by agricultural production at c.4800–4000 bp , agro‐pastoral production at c.4000–3000 bp and animal husbandry at c.3000–2200 bp , respectively. The major subsistence strategies of these three periods show considerable variation. It is very likely that these transformations of economic patterns in the prehistoric Hexi Corridor were primarily triggered by transcontinental cultural exchange and, to a lesser extent, by climate change.     

Learning by doing: enhancing hydrology lectures with individual fieldwork projects

Hydrology teaching deals with processes happening outside the classroom, which calls for active-learning methods to complement lectures. In a geography undergraduate course, new teaching methods and assessment were designed, in which students investigated a river of their choice by completing homework tasks and presenting their results on a poster. During a 3-year implementation process, the changes were evaluated using a combination of formal and informal student and lecturer feedback. Students mentioned that they enjoyed doing the project and that it helped their understanding of theory, their research skills, and their ability to select, organize and present information. Questionnaire results showed that, over the implementation period, students’ perceived value of homework increased strongly, while their perceived value of lectures remained high. In informal feedback, students noted that they enjoyed learning about where they live, preferred doing the projects individually and seeing each other’s projects, and spent more time on the coursework when assessed. When looking back in interviews, students commented that the projects had prepared them well for their dissertation and summer job. The advantage of using homework-based projects complementing lectures is the strong link between theory and practice, which could be further enhanced by discussing the homework in the lectures.     

THE BUSINESS OF WELFARE

A common narrative in welfare state research is that Sweden exemplifies a specific model of welfare, ‘the Swedish model’, or ‘the Social democratic welfare regime’. From this perspective the emerging welfare state left little room for private initiatives – the stage was set for the development of an encompassing welfare state in the 1950s. In this article I argue that this, virtually hegemonic, perspective has hindered an analysis of how private insurance co-existed and thrived within the emerging Swedish welfare state. As an alternative approach to ‘modelling’ – the concept of welfare-formation is developed to analyse mutually sustaining practices of welfare. I show how the insurance business and its protagonists influenced the settings of public pension schemes in a way that underpinned their own interests. A close cooperation with the state apparatus was fundamental for creating a trustworthy insurance market and legitimizing the business claim of fulfilling a social mission. The business adaptability in the shifting landscape of social policy also influenced perceptions of security and welfare in general. Commercial ideals became an essential dimension of the welfare state. By exploring this marginalized history – the business of welfare – the study deepens our understanding of modern welfare societies.     

Social learning as an analytical lens for co-creative planning

This article highlights the psychological dimension of social learning. Insights from psychology address the interrelated role of personal and group dynamics in social learning. This can provide a useful starting point for a rewarding use of social learning as an analytical tool in co-creative planning. Such an approach to social learning proves beneficial to (i) identify both positive and negative potential effects of social learning, (ii) untangle hidden power relationships at play at individual and small group levels in relation to social psychological factors, and (iii) discern the role of individuals and small groups within their larger contexts. The findings are empirically illustrated with a case of incremental urban development in Groningen, the Netherlands.     

Geographic accessibility to primary care providers: Comparing rural and urban areas in Southwestern Ontario

This research examines geographical accessibility to primary care providers (PCPs) across urban and rural areas of Southwestern Ontario and examines variations in the distribution of PCPs in relation to the senior population (aged 65 years and older). Information about PCP practices was provided by the HealthForceOntario Marketing and Recruitment Agency. Population data were obtained from the 2016 Census of Canada. To calculate scores for accessibility to PCPs (i.e., PCPs/10,000 population), we applied the enhanced 2-step floating catchment area method with distance decay effect within a global service catchment of 30-minute drive time. A geospatial mapping approach revealed disparities in the distribution of PCPs with a pattern of higher spatial accessibility in or around major urban areas in Southwestern Ontario. Comparative analyses were performed in association with the seniors’ population to identify how accessibility scores were mismatched with the population needs. The outcome of this study will assist researchers and health service planners to better understand the distribution of existing PCPs to address inequalities, particularly in rural areas.     

ROME'S Rise to Power. Geochemical Analysis of Silver Coinage from the Western Mediterranean (Fourth to Second Centuries BCE)

We present the results of geochemical analysis of silver coinage issued by Rome and dated between the fourth and second century BCE, which are complemented by data of coinage issued by Carthage, the Brettii, and the Greek colony of Emporion. Each of these minting authorities represents one of the major parties involved in the struggle for hegemony in the fourth to second centuries BCE Western Mediterranean region. This study retraces how the metal supply shifts in response to the transforming power relations and how this change is related to Rome's rise to the virtually uncontested ruler of the region.     

Retracing Magna Graecia's silver: coupling lead isotopes with a multi-standard trace element procedure

This study presents the results of compositional and lead isotopic analysis of coinage issued by the Greek colonies of Syracuse, Metapontum, Taras and Thurium in the fifth to third centuries bce . The data suggest that each colony in Magna Graecia, regardless of its motherland roots and despite ongoing conflicts between the cities, had access to the same silver, and that this supply was stable overall throughout their period of minting and issuing coinage. The paper retraces the silver sources of the colonies and points out a potential supply route for the metal. It includes a method development for a multi-standard quantification approach for laser ablation-inductively coupled-mass spectrometry (LA-ICP-MS) analysis of silver.     

Investigating the dietary life histories and mobility of children buried in St Gertrude Church cemetery,Riga, Latvia, 15th–17th centuries ad*

Carbon and nitrogen isotope profiles were obtained from incremental dentine analysis of 19 non-adults from a cemetery in Riga, Latvia. The research compared the life histories and diet between people buried in two mass graves and the general cemetery. The δ¹³C profiles of several children from the mass graves were similar but did not resemble the patterns seen in children from the general cemetery, suggesting that they probably represented a different population group. The rise in δ¹⁵N values towards the end of the life of four individuals from one mass grave suggests they were victims of an historically documented famine.     

Potential Discrimination of Belgian Black Marbles Using Petrography,Magnetic Susceptibility and Geochemistry

Five varieties of Belgian black marbles are investigated in order to discriminate them. Their age ranges from Frasnian (Golzinne) to Visean (Dinant, Theux, Basècle, Lives). Three methods were used: petrography, magnetic susceptibility and geochemistry of major elements and Rare Earth Elements (REE). The petrographic analyze reveals 16 microfacies reflecting very quiet environments, sporadically perturbed by more energetic phenomena like turbidites or storms. These microfacies are integrated in two depositional models: a quiet offshore setting, below or close to the storm wave base (Salet, Basècles) and a shallow but very restricted zone, protected from waves and currents (Lives and Golzinne). The magnetic susceptibility results show that all the black marbles are characterized by very low, even slightly negative values, except the Golzinne one which shows higher values. Geochemical data allow to discriminate between the Theux black marble (low SiO₂ content), and the Basècles samples (low Al₂O₃, K₂O and REE contents). These methods could be useful to determine/refine the origin of archaeological stones, even if all these analyses are destructive. Two archeologic samples were investigated in order to identify their possible origin.