In this article, a predictive model for the seismic vulnerability assessment of old Italian historic centers is presented through its direct application to a meaningful case study, the historic center of Scanno, in Abruzzi, Italy. The proposed method is calibrated on the basis of the observations carried out on similar historic centers hit by the 2009 L’Aquila earthquake and is applied in order to provide likely damage scenarios by means of fragility curves. The method is based on the evaluation of a limited number of structural and typological parameters that can be obtained by simple and rapid inspections on buildings. In addition, it is conceived in order to provide useful information on the most effective anti-seismic strategies to be implemented on urban scale for pursuing a global mitigation of the seismic risk and for the application of suitable risk reduction policies. The final aim of the article is to give an applicative vision of the method, by providing instructions on how to judge the features of the buildings that are influential on their seismic behavior, as well as by showing the potentiality of the method itself in providing likely damage scenarios, also with the support of GIS-based representations.

Seismic vulnerability assessment of urban centers is a challenging issue that needs to be faced accurately for the earthquake risk of large territorial areas. The selection of suitable methods is a crucial aspect that must be treated according to different evaluation processes, depending on the size of the problem and on the available calculation capacities. A possible strategy consists in analyzing large stocks of buildings, so to include in the analyses all those structural parameters that characterize their response and to involve the variability of the considered features. This would require a high computational effort that should be addressed to the investigation of the response of a large number of models. For this reason, simplified procedures based on engineeristic judgements, are commonly considered a viable way to be undertaken in order to predict damage scenarios. Alternatively, the attention could be focused on a limited number of buildings that are judged to be representative of the whole stock. In this case, more sophisticated analyses could be carried out and the obtained results could be extended to the whole urban center. Based on this premise, this paper presents the results obtained through the application of two different seismic vulnerability methodologies on the historic center of Campotosto, in Italy, which was hit by the last 2016 Central Italy earthquake. The first is an empirical method, applied considering a large stock of 130 buildings, which was calibrated by the authors after the 2009 L'Aquila earthquake for historical centers that are similar to the one studied in this paper. The latter, is a method based on analytical formulations dealt with by the Vulnus software, developed at the University of Padua in Italy, which was used for evaluating the seismic vulnerability of an aggregate building, which has been considered representative of the historic center. The final aim is to compare, also in the light of the damage provoked by the 2016 earthquake, the observed post-seismic scenarios, expressed in terms of fragility curves, derived from the two applied methodologies, in order to prove their reliability and to stress the possible issues related to their implementation at different scales.

Additive manufacturing, better known as 3D printing, is an innovative manufacturing technique which allows the production of parts, with complex and challenging shapes, layer by layer mainly through melting powder particles (metallic, polymeric, or composite) or extruding material in the form of wire, depending on the specific technique. Three-dimensional printing is already widely employed in several sectors, especially aerospace and automotive, although its large-scale use still requires the gain of know-how and to overcome certain limitations related to the production process and high costs. In particular, this innovative technology aims to overtake some of the shortcomings of conventional production methods and to obtain many additional advantages, such as reduction in material consumption and waste production, high level of customisation and automation, environmental sustainability, great design freedom, and reduction in stockpiles. This article aims to give a detailed review of the state of scientific research and progress in the industrial field of metal additive manufacturing, with a detailed view to its potential use in civil engineering and construction. After a comprehensive overview of the current most adopted additive manufacturing techniques, the fundamental printing process parameters to achieve successful results in terms of quality, precision, and strength are debated. Then, the already existing applications of metal 3D printing in the field of construction and civil engineering are widely discussed. Moreover, the strategic potentiality of the use of additive manufacturing both combined with topological optimisation and for the eventual repair of existing structures is presented. It can be stated that the discussed findings led us to conclude that the use of metal additive manufacturing in the building sector is very promising because of the several benefits that this technology is able to offer.

Additive Manufacturing (AM) has spread significantly in recent years, with relevant applications in many fields of research and engineering. Thanks to its distinctive production methods, AM enables the creation of parts with complex shapes that cannot be fabricated easily by employing traditional subtractive processes. 3D printing, which involves overlapping material layer by layer until the designed part is completed, shows several advantages in terms of limiting material waste, reducing production phases and postprocessing/heat treatments needs, leading to an additional benefit in terms of environmental sustainability. However, there are still limited available data on the influence of the 3D printing process on the mechanical properties of the materials that are commonly used and additional investigations are strongly demanded. So, the purpose of the present paper is to provide a useful contribution in the field of metal additive manufacturing, reporting the results of an experimental campaign carried out on 17-4 P H stainless steel, produced using selective laser melting technology. The effects of different printing orientations and scanning times on the tensile behaviour, impact strength and microhardness features of the 3D-printed products are investigated. Furthermore, the influence of an annealing heat treatment on the material mechanical performance is evaluated.