Updating Numerical Models of Masonry Arch Bridges by Operational Modal Analysis

This article aims at presenting and discussing the strategies for updating the finite element numerical modeling of stone masonry arch bridges using operational modal analysis. The study comprehended three bridges: two old ones, the St. Lázaro and the Lagoncinha bridges, and a recently constructed bridge in Vila Fria, Portugal. Updating of the bridge models is performed by comparing the numerical and experimental modal parameters. Three-dimensional detailed numerical models are used to perform modal analysis of the bridges. Experimental modal identification of the bridges is based on the measurement of their acceleration responses during normal operation. The assigned material properties are also based on available results obtained from in situ and laboratory tests and on the results of visual inspection and historical research carried out for both old bridges.     

Probabilistic life-cycle assessment and rehabilitation strategies for deteriorating structures: a case study

When it comes to existing buildings, the estimation of the structural residual bearing capacity is required to evaluate the potential for reuse/conversion. The level of detail and accuracy of surveys dramatically affect structural diagnostics. In order to optimise the experimental survey process, a simulation of the structural life-cycle may be useful.

Based on a previously developed approach of Monte Carlo simulation implemented with a damage law for the life-cycle analysis of newly designed constructions, this paper presents the method application to a historic roof steel structure. It aims to identify critical situations, assess the residual life of the system, and plan possible retrofit strategies for the building conversion.

The case study is a steel frame roof structure of the ex pig abattoir within the complex of the municipal slaughterhouse in Monza (close to Milan, Northern Italy) and protected from the Cultural Heritage Authority. The life-cycle of the structure is here investigated over different stages of the building lifespan along with the damages caused by aging and negligence. The construction was built in 1902, and abandoned in 1984. Therefore, the periods analysed are: from construction to disuse and from disuse to today. The second phase of life, still on going, has significantly sped up the degradation.

The probabilistic evaluation of failure times is discussed and the possible interventions scenarios in terms of costs, and after-maintenance reliability and safety are investigated.     

Beyond Tragedy: Differential Commoning in a Manufactured Housing Cooperative

Caught between the dual crises of declining economic opportunity and diminishing public assistance, people on the economic margins resist threats to their livelihoods by opting to share resources. The processes involved in managing these “commons” are often messy and paradoxical amid differing livelihood concerns and subject positions. Unevenness tends to emerge along new and existing lines of power. Rather than reducing such tendencies to a “tragedy” to be eliminated, I argue that grappling with uneven relations offers a more dynamic account of commoning: “differential commoning”. This paper takes as its example the residents of a “manufactured housing” community who organized as a cooperative in response to the threat of eviction. Their struggle to collectivize, I suggest, illustrates the need for a more situated conceptualization of commoning, rather than a concept defined within the rigidity of economic rationality or the homogeneity of some imagined community.     

Exceptional preservation of a prehistoric human brain from Heslington,Yorkshire, UK

Archaeological work in advance of construction at a site on the edge of York, UK, yielded human remains of prehistoric to Romano-British date. Amongst these was a mandible and cranium, the intra-cranial space of which contained shrunken but macroscopically recognizable remains of a brain. Although the distinctive surface morphology of the organ is preserved, little recognizable brain histology survives. Though rare, the survival of brain tissue in otherwise skeletalised human remains from wet burial environments is not unique. A survey of the literature shows that similar brain masses have been previously reported in diverse circumstances. We argue for a greater awareness of these brain masses and for more attention to be paid to their detection and identification in order to improve the reporting rate and to allow a more comprehensive study of this rare archaeological survival.     

Responsible girls: the spatialized politics of feminine success and aspiration in a divided Silicon Valley,USA

This article offers a comparative ethnographic examination of working-class Latina and middle-class white girls' narratives of aspiration and expressions of self-cultivation in early twenty-first-century Silicon Valley, USA. I argue that such girls' subject-making statements of aspiration and gendered practices of self-cultivation reflect their emotively charged negotiations of race and class differentiated ideals of feminine success, their experience of school and community spaces inscribed by hierarchies of race, class, and gender, and shifting political-economic circumstances. Moreover, I maintain that such statements and practices reveal girls' engagements with an open-ended gendered dynamic of responsibilization.     

Chiefdoms at the threshold: The competitive origins of the primary state

The origins of the primary state are examined, paying particular attention to the interacting complex chiefdoms that precede state formation. A comparative analysis is undertaken of the evolutionary trajectories of two well-documented cases of prehistoric complex chiefdoms in North America and Mesoamerica: Cahokia and Monte Albán. Of special concern are the strategies that the rulers of these powerful, expansionist chiefdoms pursued in response to varying conditions of local competition or resistance. The crucial difference between the two developmental outcomes, the analysis concludes, derived from the varying degrees of inter-polity competition confronted by Cahokia and Monte Albán. The higher level of inter-polity competition in Monte Albán’s case required a complete administrative transformation in order for the leadership’s goal-oriented, expansionist strategies to succeed, resulting in the successful formation of a primary state.