The Role of Uncertainties in Structural Engineering Problems: How to Manage Them in Simulation and Design

The problem of how to manage uncertainties when modeling or designing an engineering structure is briefly addressed here. Uncertainties may be relevant in the case of real structures, due to intrinsic variability of mechanical and physical properties as well as to the lack of knowledge when information are scarce and/or subject to some errors, for instance related to the test procedure. It is shown that the two mentioned sources of uncertainties must be treated in different ways, being the first unavoidable, and the second dependent on the experimental procedure adopted by the experimentalist/analyst. Different kinds of uncertainties should be then treated in different ways. The use of probabilistic tools in the first case and fuzzy number methods for the latter is studied in the first example, concerning the estimate of the strength of the concrete from a number of compression tests. The second problem addressed here concerns the identification procedure of the mechanical properties of a simple structure from dynamic test results. Also in this case, uncertainties can be due to the intrinsic variability of the properties to be identified, but also to the errors introduced in the adopted experimental procedure. Some ideas of the next steps in the research will end the paper

Observational loss database of typological precast RC buildings damaged after the 2012 Emilia Earthquake

The Emilia Earthquake occurred in 2012 in a highly industrialized area, characterized by the presence of about one firm every 9 inhabitants. The industrial heart of the region hosts many important clusters, from the Motor Valley to Food, Wellbeing, Fashion and Health devices. The main activities are conducted in production districts with several different long-span buildings like storages, deposits, warehouses, factories and silos. Among these, those made of precast reinforced-concrete (RC) elements were heavily damaged by the seismic sequence, resulting in a huge amount of economic losses due to damage to structures, products and machineries, business interruption and casualties. In the aftermath of the earthquake, the Region defined the criteria for the request of funds for the reconstruction of the buildings, the restoration of the products, the reparation of the equipment, and the temporary relocation of the activities. Thus, a large number of documents was collected reporting a variety of information concerning the seismic damage, the structural properties of the buildings, and the economic costs. In this work, through a process of progressive selection and refinement of the data, a database of seismic economic losses of damaged precast RC buildings was created. The main principles for the creation of the repository and the categorization of the information are illustrated. Hence, the losses were statistically analysed to derive useful consequence functions based on the investigation of diversified trends of the repair costs at different damage levels. The outcomes presented in this study may be adopted to perform loss assessment evaluations to guide the decision-makers in establishing priorities of structural interventions to reduce the consequences of future earthquakes in industrial areas

Structural Characterization of an Historical Building by Means of Experimental Tests on Full-Scale Elements

In order to properly design strengthening intervention of existing buildings, careful assessment of the structural behavior is certainly required. This is particularly important when dealing with historical constructions made of heterogeneous materials like masonry or stonework. In this context, this paper presents the results of knowledge process on a large monumental nineteenth century building located in Trieste. The traditional investigation approach considering a wide number of destructive tests for characterization of materials and evaluation of the structural details were not admissible due to the valuable cultural and historical importance of the building. Therefore, an alternative and not conventional investigation approach has been considered. After a wide historical research and a detailed structural survey, it has been possible to identify the main structural systems of the building. Then, to characterize the structural response, a limited number of nondestructive tests but on full-scale typological systems have been preferred to a larger number of destructive tests on specimens of the different materials. The selected experimental load tests have been conducted in order to assess the actual structural response of the main systems that constitute the building, thus allowing for a fine tuning of both the rehabilitation interventions and the numerical finite element models

Large-scale seismic damage scenario assessment of precast buildings after the May 2012 Emilia earthquake

In May 2012, two strong earthquakes hit the northern Italy revealing the significant seismic vulnerability of precast reinforced concrete structures and causing severe damage and many collapses, and high economic losses. After the lesson learnt from these events, more reliable seismic design criteria have been established for the design of new structures and different approaches have been proposed for the seismic assessment of the existing structures. In this context, the paper presents the results of a first application of the PRESSAFE-disp method, recently proposed by the authors, allowing to define the fragility curves of precast RC buildings at various limit states, including collapse. A stock of 91 precast buildings in the industrial area of San Felice sul Panaro (Modena) was selected as a benchmark case study to verify the reliability of the method in assessing seismic damage scenarios. In particular, with reference to the 2012 seismic ground-motion, two large-scale stochastic models are outlined to predict the number of the buildings collapsed in the area. The first one is based on a Monte Carlo simulation which incorporates the evaluation of the uncertainties, while the second one is a direct simplified calculation. Comparative considerations on the outcomes of the two methods for different seismic intensities are discussed, including the directionality effect of the ground-motion. To test the soundness of the simulations, the results of the two methods are compared with the real data collected through in-situ surveys. The procedures proposed here result, on average, in good agreement with the observed damage scenario. It is worth noting that, due to the inherent simplicity of the methods, they could be implemented to perform scenario-based seismic loss assessments to estimate the financial consequences of an earthquake affecting one or more industrial areas, and to drive the decision-making process for the seismic retrofit of existing precast RC buildings

REINSER 2022 International Conference for Sharing Best Practices: Economic and Social Integration of Refugees and Asylum Seekers through Social Entrepreneurship. Book of abstracts

This book collects the proceedings of the Conference “Economic and Social Integration of Asylum Seekers and Refugees through Social Entrepreneurship – International Conference for Sharing Best Practices” held at the Forlì Campus of the Alma Mater Studiorum - University of Bologna on the 10th and 11th of March 2022. The organisation of the conference took place in the framework of the Interreg-ADRIONfunded project REInSER – Refugees’ Economic Integration through Social Entrepreneurship – which brings together partners from six countries of the ADRION area, namely, Slovenia, Italy, Greece, Bosnia and Herzegovina, Serbia, and Croatia. The project aims to improve the economic and social integration of refugees and asylum seekers in host societies of the ADRION programme area by using social economy approaches and, in particular, social entrepreneurship (SE). The long-term objective is to enhance the possibilities for refugees to become active economic actors and agents of their integration in a given host society, contributing to the local and regional sustainable economic development by generating employment and supporting the creation of new social and responsible businesses

Empirical seismic fragility for the precast RC industrial buildings damaged by the 2012 Emilia (Italy) earthquakes

The paper analyses the seismic fragility of precast reinforced concrete buildings using observational damage data gathered after the 2012 Emilia earthquakes that struck Northern Italy. The damage level in 1890 buildings was collected, classified and examined. Damage matrices were then evaluated, and finally, empirical fragility curves were fitted using Bayesian regression. Building damage was classified using a six-level scale derived from EMS-98. The completeness of the database and the spatial distribution of the buildings investigated were analysed using cadastral data as a reference. The intensity of the ground motion was quantified by the maximum horizontal peak ground acceleration, which was obtained from ShakeMaps. Copyright © 2017 John Wiley & Sons, Ltd

On the use of mode shape curvatures for damage localization under varying environmental conditions

A novel damage localization method is introduced in this study, which exploits mode shape curvatures as damage features, while accounting for operational variability. The developed framework operates in an output-only regime,that is, it does not assume availability of records from the influencing environmental/operational quantities but rather from response quantities alone. The introduced tool comprises 3 stages pertaining to training, validation, and diagnostics. During the training stage, a representation of the healthy, or baseline, structural state is acquired over varying operational conditions. A data matrix is formulated, whose individual columns correspond to mode shape curvatures at distinct operational conditions, and principal component analysis (PCA) is applied for extraction of the imprints of separate operational sources on these curvatures. To this end, a residual matrix between the original and the PCA mapped data is formed serving for statistical characterization of each mode. Subsequently, during the validation and diagnostics stages, the mode shape curvature matrices for the currently inspected structural state are assembled and the same PCA mapping is enforced. A typical hypothesis test and a corresponding damage index are then adopted in order to firstly detect damage, and to secondly localize damage, should this exist. The implementation of the proposed method in 2 numerical case studies confirms its effectiveness and the encouraging results suggest further investigation on operating structural systems. ISSN:1545-2255 ISSN:1545-226

Seismic risk assessment of a new RC-framed skin technology for integrated retrofitting interventions on existing buildings

A RC-framed-skin technology for the integrated seismic and thermal retrofitting interventions on existing buildings, recently proposed by some of the authors, is thoroughly investigated. By means of numerical analyses, its effectiveness and suitability within the framework of seismic risk class assessment is proved. The system is composed of a RC-framed structure with an external reinforced plaster layer that does not offer a structural contribution to the capacity of the system in ultimate conditions, but which can be effective by increasing the lateral stiffness in serviceability conditions. The system is realized from the outside of the existing building so guaranteeing limited invasiveness of the intervention and preventing the interruption of the building use by their occupants. An existing RC building, representative of a typical example of the Italian building stock, is analyzed as a case study, and its seismic risk class upgrade, obtained by the proposed strengthening intervention, is assessed by non-linear static analysis. The numerical models are developed within the OpenSees framework. The Expected Annual Loss (EAL) parameter, together with the Life Safety Index (LS-I), are chosen as synthetic measures that include both aspects related to Ultimate Limit state (ULS) and Serviceability Limit State (SLS) conditions. The risk class accounting for or disregarding the contribution of the external reinforced plaster are finally compared

Cross-national vaccine concerns and predictors of vaccine hesitancy in not-fully vaccinated individuals: findings from USA, Canada, Sweden, and Italy

Vaccine hesitancy is a key contributor to reduced COVID-19 vaccine uptake and remains a threat to COVID-19 mitigation strategies as many countries are rolling out the campaign for booster shots. The goal of our study is to identify and compare the top vaccine concerns in four countries: Canada, Italy, Sweden, and the USA and how these concerns relate to vaccine hesitancy. While most individuals in these countries are now vaccinated, we expect our results to be helpful in guiding vaccination efforts for additional doses, and more in general for other vaccines in the future. We sought to empirically test whether vaccine related concerns followed similar thematic issues in the four countries included in this study, and then to see how these themes related to vaccine hesitancy using data from a cross-sectional survey conducted in May 2021. We applied CFA and created vaccine concern scales for analysis. We then utilized these results in regression-based modeling to determine how concerns related to vaccine hesitancy and whether there were similar or different concerns by country. The results quantitatively highlight that the same vaccine related concerns permeated multiple countries at the same point in time. This implies that COVID-19 vaccination communications could benefit from global collaboration

Exploring the association between misinformation endorsement, opinions on the government response, risk perception, and COVID-19 vaccine hesitancy in the US, Canada, and Italy

The COVID-19 pandemic has highlighted the adverse consequences created by an infodemic, specifically bringing attention to compliance with public health guidance and vaccine uptake. COVID-19 vaccine hesitancy is a complex construct that is related to health beliefs, misinformation exposure, and perceptions of governmental institutions. This study draws on theoretical models and current data on the COVID-19 infodemic to explore the association between the perceived risk of COVID-19, level of misinformation endorsement, and opinions about the government response on vaccine uptake. We surveyed a sample of 2697 respondents from the US, Canada, and Italy using a mobile platform between 21-28 May 2021. Using multivariate regression, we found that country of residence, risk perception of contracting and spreading COVID-19, perception of government response and transparency, and misinformation endorsement were associated with the odds of vaccine hesitancy. Higher perceived risk was associated with lower odds of hesitancy, while lower perceptions of government response and higher misinformation endorsement were associated with higher hesitancy