evaluation of the variability contribution due to epistemic uncertainty on constitutive models in the definition of fragility curves of rc frames

Abstract In the framework of uncertainty propagation in seismic analyses, most of the research efforts were devoted to quantifying and reducing uncertainties related to seismic input. However, also uncertainties associated to the definition of constitutive models must be taken into account, in order to have a reliable estimate of the total uncertainty in structural response. The present paper, by means of incremental dynamic analyses on reinforced concrete frames, evaluates the effect of the epistemic uncertainty for plastic-hinges hysteretic models selection. Eleven different hysteretic models, identified based on literature data, were used and seismic fragility curves were obtained for three different levels of maximum interstorey drift ratio. Finally, by means of analysis of variance techniques, the paper shows that the uncertainty associated to the hysteretic model definition has a magnitude similar to that due to record-to-record variability

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

Experimental and numerical evaluation of fiber-matrix interface behaviour of different FRCM systems

Abstract Fiber Reinforced Cementitious Matrix (FRCM) composites are a relatively new strengthening system family, whose mechanical behavior is strongly affected by the wide array of possible inorganic matrices and composites fabrics that can be used and coupled together. Structural tests highlighted that global capacity of the system is strongly affected by fabric-matrix adhesion mechanism. In the present paper, the experimental results of tensile and single-lap shear tests, aimed to define mechanical properties of four FRCM types, are discussed and compared. For each system type, the failure modes for both types of test have been physically identified and clarified. The following development of detailed finite element models, carefully reproducing the mechanical behavior of the different layers of the strengthening system, allowed for the proposal of a reliable shear stress-slip relation for the fiber-matrix interface. The experimental outcomes showed the relevant dispersion of the results in terms of performance, effectiveness and failure mechanisms exhibited by the different FRCM types while the numerical interpretation allowed for a better understanding of the reasons and the parameters behind them

Psychosocial and behavioral impact of COVID-19 in autism spectrum disorder: an online parent survey

The 2019 coronavirus disease (COVID-19) outbreak could result in higher levels of psychological distress, especially among people suffering from pre-existing mental health conditions. Young individuals with autism spectrum disorders (ASD) are particularly at risk due to their vulnerability to unpredictable and complex changes. This study aimed to investigate the impact of the COVID-19 pandemic on ASD individuals, whether any pre-pandemic sociodemographic or clinical characteristics would predict a negative outcome, and to narratively characterize their needs. Parents and guardians of ASD individuals filled out an online survey consisting of 40 questions investigating socio-demographic and clinical characteristics of their children, impact of the COVID-19 outbreak on their wellbeing and needs to deal with the emergency. Data were available on 527 survey participants. The COVID-19 emergency resulted in a challenging period for 93.9% of families, increased difficulties in managing daily activities, especially free time (78.1%) and structured activities (75.7%), and, respectively, 35.5% and 41.5% of children presenting with more intense and more frequent behavior problems. Behavior problems predating the COVID-19 outbreak predicted a higher risk of more intense (odds ratio (OR) = 2.16, 95% confidence interval (CI) 1.42-3.29) and more frequent (OR = 1.67, 95% CI 1.13-2.48) disruptive behavior. Even though ASD children were receiving different types of support, also requiring specialist (19.1%) or emergency (1.5%) interventions in a relatively low proportion of cases, a number of needs emerged, including receiving more healthcare support (47.4%), especially in-home support (29.9%), as well as interventions to tackle a potentially disruptive quarantine (16.8%). The COVID-19 outbreak has undoubtedly resulted in increased difficulties among ASD individuals

LCA of virgin and recycled materials to assess the sustainability of paved surfaces in agricultural environment

The construction sector is currently characterized by high raw material consumption but also by the production of high volume of wastes, mostly constituted by construction and demolition wastes that could be valorized promoting the use of recycled aggregates in substitution of raw aggregates. A promising application for recycled aggregates is for the realization of rural roads and pavements. The agricultural context, characterized by particular type of traffic and need to balance performance and integration with the environment, is suited for the use of these materials for paved surfaces since it can promote, in several cases, the adoption of rural circular processes internal to the farm. However, if on one hand the adoption of recycled aggregates could increase the sustainability of the sector, on the other it could increment the environmental loads if the whole process is not properly organized. For instance, the negative effects of transportation operations can cancel the environmental benefits if high distances between the production and the destination sites are present. This work reports the results of the Life Cycle Assessment (LCA), from cradle-to-gate, of four different construction aggregate classes that can be used for the realization of rural roads, pavements and forecourts, and paved areas in agricultural environment. The first three materials are recycled aggregates produced by the recycling processes of construction and demolition waste and the fourth type refers to gravel aggregates produced from natural resources. The Life Cycle Assessment was realized using site-specific primary data from the local territorial context and paying particular attention to transportation-related impacts, land use, avoided landfill and preservation of non-renewable resources. The results of the work clearly show that the environmental impacts in both scenarios of recycled aggregates are lower than the virgin aggregate scenario. In fact, considering the midpoint categories, the recycled materials proved to be more virtuous in almost all the indicators, with the exception of except for the marine eutrophication. The most significant gap between virgin and recycled materials has been in global warming and marine and freshwater eco-toxicity

3D numerical modelling of temperature and humidity index distribution in livestock structures: a cattle-barn case study

In dairy cattle farming, heat stress largely impairs production, health, and animal welfare. This study aims to develop a workflow and a numerical analysis procedure to provide a real-time 3D distribution of the temperature and humidity index (THI) in a generic cattle barn based on temperature and humidity monitored in sample points, besides characterising the relationship between indoor THI and outside weather conditions. This research was carried out with reference to the study case of a cattle barn. A model has been developed to define the indoor three-dimensional spatial distribution of the Temperature-Humidity Index of a cattle barn based on environmental measurements at different heights of the building. As a core of the model, the Discrete Sibson Interpolation method was used to render a point cloud representing the THI values in the non-sampled areas. The area between 1-2 meters was emphasised as the region of most significant interest to quantify the heat waves perceived by dairy cows. The model represents an effective tool to distinguish different areas of the animal-occupied zone characterised by different values of THI

Microventilation system improves the ageing conditions in existent wine cellars

Background and Aims: The importance of indoor environmental conditions in a cellar is well known and continuously investigated. The process of wine ageing consists of several steps, during which temperature (T) and relative humidity (RH) play a fundamental role as the quality of the final product is strongly related to stable and suitable environmental conditions. Critical factors, such as mould growth or wine evaporation, have emerged when ventilation has proved to be insufficient or poorly designed. The limitation of stagnant areas and the homogeneity inT and RH provide for proper wine conservation; however, unwanted local conditions can occur in the zones with insufficient air exchange. Methods and Results: Considering these aspects, a controlled microventilation and monitoring system was installed in a case study cellar, and T and RH were monitored for 1 year. The data have been analysed to investigate criticalities of the environmental conditions. The ventilation was activated in specific critical conditions to increase the homogeneity of the T and RH in the critical zones. The results show that the microventilation system improves the homogeneity of both T and RH without affecting the average values. Conclusions: The study demonstrated the efficacy of the system and indicated possible modifications to improve system performance. Significance of the Study: The system proved to be a useful tool for both improving the environmental conditions and providing useful information to the winemakers about the ageing conditions