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Vulnerabilità ed esposizione sismica del costruito residenziale del centro storico di Alcamo
No full textVulnerabilità ed esposizione dell'edilizia residenziale del centro storico di Alcam
Vulnerability and Seismic Exposure of Residential Building Stock in the Historic Center of Alcamo
Full text linkThe influence of exposure evaluation methodology in the assessment of the seismic vulnerability of the residential building stock in the historic center of Alcamo, a town of 45,000 inhabitants in Western Sicily (Italy), hit by an earthquake in 1968, is evaluated in this study. A comparison of exposure estimates on the basis of the description of the residential building stock according to two different approaches is performed. The first, typical of seismic vulnerability assessment procedures at a territorial scale, refers to the description of residential building stock through an accurate typological description, conducted using the CARTIS survey form. The form allows for a detailed description and survey of the prevailing ordinary building types within areas characterized by the homogeneity of the building fabric in terms of age of construction, structural characteristics, construction techniques, and distribution of types. The detailed description of building types allows for the assessment of exposure at the municipal scale based on an estimate of the total number of units and the percentage of each type within each compartment, obtained by interviewing local technicians. The second is based on a similar survey at the building scale, namely, drawing up a form for each building. The comparison of exposure and damage scenarios obtained with the two methods proves that the approximations provided by the compartment-scale survey are compatible with the purposes of an assessment of vulnerability and damage scenarios at the territorial scale
DECISION SUPPORT TOOLS FOR ECONOMIC RESOURCES ALLOCATION IN SEISMIC RETROFITTING OF BUILDINGS
No full textA vast number of existing masonry and RC buildings in Italy is located in medium-to-high level seismic hazard regions and they are particularly vulnerable to earthquakes. Although strengthening interventions are urgent, resources are limited and seismic retrofitting the whole existing building stock is not practical. Thus, it is necessary to optimize the allocation of resources for strengthening interventions, taking into account the cost constrains and those variables connected to the repair and indirect costs, such as number of inhabitants, the priority and the size of the building, the vulnerability level. This work addresses the decision issue related to the optimal budget allocation for proactive strengthening actions on buildings located in seismic areas and reactive repair after an earthquake. The goal is to minimize the number of uninhabitable buildings considering their capacity in terms of residents. A two-stage stochastic model with recursions is used to perform the analyses, assuming to have a maximum cumulative budget which can be used for proactive (strengthening) and/or reactive (reconstruction) actions. The solution of this stochastic problem is compared with the solution of the problem where the budget is used only for reactive actions. The outcomes are presented and discussed with reference to a real case of a small town in Sicily
Influence of Cross-Section Shape and FRP Reinforcement Layout on Shear Capacity of Strengthened RC Beams
Full text linkThe evaluation of the shear capacity of an FRP-strengthened reinforced-concrete beam is challenging due to the complex interaction between different contributions provided by the concrete, steel stirrup and FRP reinforcement. The shape of the beam and the FRP inclination can have paramount importance that is not often recognized by the models that are suggested by codes. The interaction among different resisting mechanisms has a significant effect on the shear capacity of beams, since it can cause a reduction in the efficiency of some resisting mechanisms. A comparative study of the performance in the shear resistance assessment provided by three models with six different effectiveness factors (R) is performed, considering different cross-section shapes, FRP wrapping schemes, inclination and anchorage systems. The results revealed that the cross-section shape, the FRP inclination and the efficiency of the FRP anchorages have a significant effect on the shear strength of beams. The analysis results show that the three models are able to provide an accurate average estimation of shear strength (but with a coefficient of variation up to 0.35) when FRP reinforcement orthogonal to the beam axis is considered, while a significant underestimation (up to 19%) affected the results for inclined FRP reinforcement. Moreover, all the models underestimated the resistance of beams with a T section
EARTHQUAKE-RESILIENT RC BUILDINGS WITH STEEL-CONCRETE TRUSSED BEAMS AND FRICTION DAMPERS
No full textThis study investigates the effects of friction damping devices in the structural joints of RC buildings endowed with semi-prefabricated hybrid beams and traditional RC columns. The beams are made with a steel trussed skeleton welded to a bottom thin plate, which is finally completed on-site by casting a concrete core. These beams have been widely adopted in both civil and industrial buildings also in seismic areas for several decades. Therefore, it is essential to approach new design strategies for the mitigation of the seismic effects. To this scope, the adoption of friction damping devices is discussed here; their effects are analysed when dampers are placed at Beam-to-Column Connections (BCCs) and Column-Base Connections (CBCs). With reference to the friction devices placed at BCCs, the efficacy of two different proposed solutions is shown. The first solution is characterized by a friction device with curved slotted holes, while the second solution consists in the adoption of curved slotted holes again, in presence of added perfobond connectors. Then, a CBC are studied, namely a self-centering system with friction pads and preloaded bolts. The analyses are conducted by modelling the structure using the Finite Element Method (FEM). FEM models are created first to simulate the monotonic and cyclic response of the damping devices at the joints. Then, the seismic response of an ideal 2-storey RC frame is simulated by means of pushover analyses and non-linear time history analyses. The main results show that, for BCCs, the solution with curved holes and perfobond connectors is the most effective in preventing beam, column and joint from damage and it is suitable for exhibiting adequate dissipative capacity ensured by flexural behaviour dominated by wide and stable hysteresis loops. On the other hand, for CBC, the results show that the self-centering friction devices effectively limit both peak and residual drifts, avoiding column-base plasticisation. Finally, experimental tests are conducted for the characterization of a friction material, and a BCC is tested under cyclic loading, showing promising performance in providing low-damage behaviour and good dissipation capacity
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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