Integrated approach for post-fire reinforced concrete structures assessment

In order to assess decay in the mechanical characteristics of re-exposed Reinforced Concrete (RC), it is crucial to recon- struct the temperature time history and the evolution of strain and stress elds. In this paper, the state of the art of assessment methods is presented and applied to a real structure damaged by re. It is a prestressed RC industrial warehouse located in the outskirts of the city of Cagliari (Italy). The collected data of several assessment methods are presented in order to produce the owchart of an integrated approach for post- re investi- gation. Among the various techniques, the authors highlight a thorough laser scanner geometric survey and destructive and non-destructive testing. In addition, the temperature distribu- tion and its time history has been reconstructed by means of optical and Scanning Electron Microscopy, X-ray diffractom- etry, Thermogravimetric Differential Thermo-Analysis and calibrated Colorimetry. Actually, refurbishment is needed, but the structure withstood the re very well. Central columns displayed the most impor- tant damage, and several beams presented important de ec- tions having lost the prestressing actions of the tendons

Workability and chemical-physical degradation of limestone frequently used in historical Mediterranean architecture

Sedimentary rocks are among the most used in historical buildings, as they are more readily available in the area and because they are also more easily extractable, in virtue in general of lower mechanical resistance. among these the most used are limestones and sandstones. The former are represented by a remarkable variety of lithologies, with highly variable characteristics, passing from the almost pure, massive and not very porous limestones, to those with a variable arenaceous-clayey component which instead are characterized by a low compactness and consequent high porosity (up to 35%). In this study the calcarenites present in two geographic sectors of Sardinia are dealt with, by comparing them with similar showers present in other territorial contexts of the Mediterranean. The mineralogical-petrographic analyzes by optical microscope and XRD analysis of the "Pietra Cantone" limestone of Cagliari (south Sardinia) show, besides calcite, the presence of phyllosilicates and various other accessory minerals. SEM analyses show a very weak physical-mechanical microstructure

Pyroclastic Stones as Building Materials in Medieval Romanesque Architecture of Sardinia (Italy): Chemical-Physical Features of Rocks and Associated Alterations

The paper discusses the chemical-physical-petrographic features and decay processes of San Nicola Church (11th−14th century) building materials, one of the most representative Medieval Churches in Sardinia, stylistically attributable to the Romanesque architecture. The monument was built up into two stages and shows a characteristic size uniformity of the ashlars. The masonry is mainly made up of rhyodacitic pyroclastites belonging to the Sardinian Eocene-Miocene mag- matic phase (38–15 My). These volcanic rocks were widely used in Medieval architecture for the excellent workability, but its minero-petrographic features greatly favor the decay, due to the action of chemical-physical alteration processes. Although the alteration degree and macroscopic forms of decay vary from zone to zone in the monument, according to the different compositional features of the volcanic stones, weathering and exposure condition, the pyroclastic rocks are generally affected by greater alteration than other igneous lithotypes, due to their petrographic- volcanological characteristics (e.g., low-medium welding grade, medium-high porosity). The results concerning mineralogical and petrographic features, respectively, carried out by the application of X-Ray Powder Diffraction (XRPD), Optical Microscope (OM), and Scanning Electron Microscope (SEM) techniques, both on fresh building rocks and associated alterations, are here presented and discussed. Furthermore, the relationships between fresh pyroclastites and altera- tion processes affecting these rocks will be discussed

Cardiac Autonomic Control and Neural Arousal as Indexes of Fatigue in Professional Bus Drivers

Background: Bus driving is a mentally demanding activity that requires prolonged attention to ensure safety. The aim of the study was to assess mental fatigue caused by driving a public bus and to find a profile of workers at higher risk. Methods: We evaluated changes of critical flicker fusion (CFF) (index of central arousal) and heart rate variability (HRV) (index of autonomic balance) in a 6-hour driving shift on a real route, in 31 professional bus drivers, and we tested the influence of personal factors such as sleep quality, BMI, and age. Paired t test was used to test differences of CFF and HRV between both initial and final phase of driving, while multiple linear regression tested the influence of personal variables on the indexes of mental fatigue. Results: Results showed that CFF significantly decreased after 6 hours of bus driving (41.91 Hz, sd 3.31 vs. 41.15 Hz, sd 3.15; p = 0.041), and heart rate significantly decreased in the final phase of driving, with respect to the initial phase (85 vs. 78 bpm, p = 0.027). Increasing age (beta =-0.729, p = 0.022), risk of obstructive sleep apnea syndrome (beta =-0.530, p = 0.04), and diurnal sleepiness (beta =-0.406, p = 0.017) showed a significant effect on influencing mental fatigue. Conclusion: Elderly drivers at higher risk of sleep disorders are more prone to mental fatigue, when exposed to driving activity. Monitoring indexes of central arousal and autonomic balance, coupled with the use of structured questionnaires can represent a useful strategy to detect profile of workers at higher risk of mental fatigue in such duty

Mobility and land-use system in the sport mega-events. The case of the Cagliari stadium (Sardinia, Italy)

The evaluation of the mobility of the Sport infrastructures associated with Mega Events (SMEs), as football stadiums, and, in particular, the modal choices adopted by participants, are the focus of this study. Mobility, geographical aspects and urban planning that characterize a city hosting the SME are the main fields of investigation. In particular, in Italy there is a limited collaborative convergence among technical and scientific principles and the rules expressed by the Italian National Olympic Committee (CONI), to which an obsolete regulation for the accessibility of sports facilities refers. The progressive awareness of the communities on the fundamental role of sustainable mobility, energy efficiency, reduction of air pollution, also deriving from the impulse of the 2030 objectives, highlights how it is illusory to think of reaching them without gradual changes in the lifestyle of the communities themselves through political rules of urban development. Furthermore, the pandemic and the recent energy crisis highlighted the need to develop integrated systems - considering geographical, urban and regional planning, transport and mobility issues capable of innovating to improve planning activities and the quality of urban life

Geomaterials and decay forms of the coastal towers of Piscinni and Foghe, Weastern Sardinia

[EN] The distribution of Coastal Towers in Sardinia testify that foreign invasions, which occurred several times over the centuries, were particularly frequent and dangerous. The beginning of the eighth century signed an increase of the attacks from the sea. The most of Coastal Towers were built in the period of Spanish rule, from 1583 to 1720. Despite numerous restorations over the years, many of these defensive structures are in critical conditions, some also affected by structural collapse. The building materials are closely related to local geological outcrops, and consist of sedimentary, magmatic and metamorphic rocks. Study of different lithotypes allowed assessing the vulnerability of different materials in different environmental conditions. Salts, transported by aerosols and deposited inside the porous structures, are the principal cause of decay of the building materials. Chemical-physical and mineralogical-petrographic analyses, performed on some Towers allowed making some general assessments on their conservation status and restoration projects.Carcangiu, G.; Meloni, P.; Palomba, M.; Cocco, O.; Sitzia, F.; Murru, A.; Carboni, M.... (2015). Geomaterials and decay forms of the coastal towers of Piscinni and Foghe, Weastern Sardinia. En Defensive architecture of the mediterranean: XV to XVIII centuries. Vol. I. Editorial Universitat Politècnica de València. 345-352. https://doi.org/10.4995/FORTMED2015.2015.1753OCS34535

Durability of repair mortars used in restoration of a Sardinian coastal tower: assessment after ten years

[EN] This study reports the results of investigations on conservation conditions of an ancient tower, called Torre del Pozzo, located in the S-W coast of Sardinia, restored about ten years ago. The tower suffers from serious problems related to vulnerability of building materials, particularly limestone and sandstones and aerial lime mortar with poor physical-mechanical properties. Over the centuries the materials were subjected to aggressive actions (wind corrasion and salt crystallization) causing an intense erosion of the walls with consequent partial collapse of the structure. About ten years ago a restoration involved the mortars and only the replacement and integration of ashlars deteriorated. After about 10 years from this intervention, some inspections have been carried out in order to assess the effectiveness of the intervention and the state of preservation of the tower. This paper focuses on analyses and tests carried out to assess condition and durability of the repair mortars.Meloni, P.; Carcangiu, G.; Palomba, M.; Enzo, S.; Carboni, M.; Cocco, O.; Casti, M.... (2015). Durability of repair mortars used in restoration of a Sardinian coastal tower: assessment after ten years. En Defensive architecture of the mediterranean: XV to XVIII centuries. Vol. II. Editorial Universitat Politècnica de València. 397-44. https://doi.org/10.4995/FORTMED2015.2015.1761OCS3974

Multidisciplinary study of biological parameters and fatigue evolution in quay crane operators

In intermodal terminals the handling of containers and the number of accidents still depends on a wide range of human errors due to fatigue despite the automation level reached nowadays. For this reason it is very important to increase knowledge about the factors affecting the propensity of operators to make errors, increasing the chance of accidents happening. The aim of this work is to propose a novel approach to assess fatigue and performance lev els in quay crane operators as a function of physiological parameters and of the many varying boundary conditions encountered in daily work. During their work, quay crane operators have to deal with variable environmental conditions, such as task type, wind speed and direction, lighting conditions that redu ce visibility that can require an exacting level of attention. In the trial eight operators have been examined in a session lastin g four hours. All actual conditions are reproduced through a fully imme rsive quay crane simulator. The operator completes the assigned task (the same for each one) and can see through four wide monito rs a high quality virtual reality view of the simulation. Most biological parameters are acquired using different devices including a Holter ECG monitor, electromyographic monitoring the four trunk muscles most involved in the test, eye tracker and seat - body pressure interface for both seat pan and backrest. Changes in physiological parameters have been monitored during the trial and interesting correlations with performance levels and boundary conditions ha ve been f ound for each operator, in accord ance with their age and skills. The present study can form the basis for further investigations aimed at developing a cost effective, reliable and robust system for monitoring increasing fat igue and for predicting the critical conditions that may result in an acciden

The Association of childhood asthma and <i>Helicobacter pylori</i> infection in Sardinia

Background: It has been suggested that Helicobacter pylori infection might reduce the risk of atopic conditions, such as asthma, in childhood. This risk reduction could relate to the “hygiene hypothesis” which proposes an association between childhood exposure to microbes and risk of atopy. Objectives: To examine the association between Hp infection and childhood acquired asthma in Sardinia. Patients and Methods: Children from Northern Sardinia who were between the ages of 10 months to 6 years and were screened for Hp infection in 1994-1995 using IgG serology, were asked in 2012, whether they had developed asthma and/or allergic disease in pediatric age, using the global initiative on asthma guidelines questionnaire. Results: A total of 64 children participated in the study. The sero-positivity for Hp infection was 14.1%. Eleven (17.2%) children had a confirmed diagnosis of asthma with onset before the age of 5 years, 85.9% were Hp negative and 14.1% Hp positive. Eight children of the 53 without asthma were Hp positive (15%) compare to one children positive for the infection of the 11 patients (0.09%) with asthma (8/53 vs. 1/11; P = 0.6). The majority of children (73%) were from urban areas and 43.8% had a family history of asthma or allergies. Multiple logistic regression analysis was not able to find a studied variable, including Hp infection, significantly associated with pediatric asthma. Conclusions: Our results speak against Hp infection itself playing a role to protect from the risk to develop childhood asthma although household hygiene was not directly assessed