<p><strong>Abstract.</strong> In this paper, an integrated analysis of the geometric and photogrammetric surveys on a 19th century bridge is proposed as an instrument for the comprehension of the historical evolution of its structural disorders, of its present conservation status and as a reliable base to define future interventions. The studied 20 arches brick masonry bridge in Northern Italy, that reaches the length of nearly 600 meters, constitutes a very interesting case study, not only for the technical and structural issues related to its restoration and use (with increased traffic loads) but also for its geometry, that has strict connections with the design methods that lead its construction, based on proportions, and whose changes in time embody the present symptoms of possible structural illnesses. Moreover, the bridge shows many decay phenomena, whose treatment will require a large part of the restoration resources. For this reason, a precise quantification of the affected surfaces, also in the curved parts, is important for the definition of conservative interventions. To this aim, possible methods of mapping and measuring the decay phenomena starting from the photogrammetric survey are also discussed.</p>
Realization of first-aid devices for the safety of heavily damaged structures of the Cultural Heritage assets is one of the main problems in the post-earthquake emergency phase. However, the adopted solutions, characterized by the utmost urgency, often appear uneven, ineffective and expensive. Six years after the earthquake in Emilia Romagna Region, which damaged numerous historical buildings, above all churches, it seems worthwhile to reflect on the management of the post-earthquake emergency and reconstruction interventions. As a matter of fact, in 2012, many Public Institutions were unprepared to deal with such an event: the lack of an appropriate knowledge about how to intervene in such conditions has led to solutions that are unnecessarily expensive, technically ineffective and, sometimes, even harmful for the building itself. Frequently, the strengthening devices had to be entirely redesigned during the subsequent phase of definitive intervention, entailing additional costs for the removal of those realized in the emergency phase. The cases in which the provisional devices have been designed in preparation for the final strengthening, sometimes even becoming definitive themselves, are rare. Therefore, this experience has raised some reflections concerning the functionality of the temporary safety measures. It has been noticed that an appropriate design of the provisional devices is fundamental in order to avoid interventions that could compromise the value of the architectural asset, to allow the knowledge of the structure for designing the definitive strengthening and to consider the permanent implications of such safety measures. This note presents some case-studies related to strengthening actions following the 2012 earthquake in Emilia, aiming to identify possible solutions for implementing the first-aid interventions in an integrated way with the subsequent strengthening phase in order to significantly reduce economic, material and time costs.
A hands-on approach to introduce
the chemical elements and the
atomic structure to elementary/middle school students is described.
The proposed classroom activity presents Bohr models of atoms using
common and inexpensive materials, such as nested plastic balls, colored
modeling clay, and small-sized pasta (or small plastic beads).
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