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• A methodology to set credible speed limits is provided. • The methodology considers the roadway design characteristics and the drivers' operating speeds. • Speed prediction models and driving simulator experiments have been integrated and compared. • The methodology has been tested on the A16 Naples–Canosa motorway, section Baiano–Candela, in southern Italy. • The proposed safety countermeasures have a benefit/cost ratio of 4.66. Speed management is an integral part of the Safe System approach and tackling unsafe speeds is the first action to fix a transport system that fails to protect people. There is a consensus that where traffic speeds are a safety issue, lowering the speed limit is considered "reasonable and safe" for conditions. Nevertheless, not only should a speed limit be reasonable and safe, but it should also be credible. Otherwise, that posted speed limit is likely to be ignored. In many instances, speed limits are not credible and highway agencies still need guidance on appropriate procedures to set credible speed limits. The main objective of this study is to propose and test a novel methodology to set credible speed limits, based on the integration of the results achieved by numerical analyses and driving simulator experiments. The proposed methodology is innovative since it takes into consideration both the design characteristics of the road infrastructure according to a specific procedure as well as the drivers' operating speeds, which are evaluated using the results of both speed prediction models and driving simulator experiments. The methodology was tested to set new speed limits on the A16 Naples–Canosa motorway, section Baiano–Candela, in southern Italy, where a posted speed limit of 80 km/h is installed in both travel directions and a new speed limit of 100 km/h is proposed, based on the results of the experiments developed within the methodology. Since the speed limit selection is associated with the expected crash frequency, the final selection of the speed limit should take into account also a safety impact assessment, considering both the expected change in the speed distribution as well as the effects of the safety countermeasures implemented in association to the speed limit change. In this study, the proposed safety countermeasures are the activation of four sections with point-to-point speed control and targeted measures at 45 curves, consisting of (1) high friction surface treatments, (2) correction of superelevation deficiencies, (3) installation of curve warning signs, chevrons, and sequential flashing beacons, and (4) shoulder rumble strips. The safety impact assessment shows that the increase in the speed limit combined with the implementation of the proposed safety countermeasures allows a crash reduction of 23%. The estimated benefit/cost ratio of the safety countermeasures is 4.66. [ABSTRACT FROM AUTHOR]

In this paper, a three-dimensional (3D) numerical model based on the finite element method (FEM) is developed to determine the fluid flow and heat transfer phenomena in a real multi-tube downhole heat exchanger (DHE), designed ad hoc for the present application, considering natural convection inside a geothermal reservoir. The DHE has been effectively installed and tested on the island of Ischia, in southern Italy, and the measurements have been used to validate the model. In particular, the authors analyze experimentally and numerically the behavior of the DHE based on the outlet temperature of the working fluid, thermal power, overall heat transfer coefficient, and efficiency. Furthermore, the influence of the degree of salinity on the performance of the DHE has been studied, observing that it degrades with the increase in the degree of salinity. The results show that the DHE allows to exchange more than 40 kW with the ground, obtaining overall heat transfer coefficient values larger than 450 W/m2 K. At the degree of salinity of 180 ppt, a decrease in the efficiency of the DHE of more than 8% is observed. [ABSTRACT FROM AUTHOR]

This work describes a procedure for building a high-quality 3D model of a rocky pinnacle in the Dolomites, Italy, using Structure from Motion (SfM) techniques. The pinnacle, known as "Campanile di Val Montanaia", is challenging to survey due to its high elevation and sub-vertical cliffs. The construction of the 3D model is the first step in a multi-disciplinary approach to characterize the rock mass and understand its behavior and evolution. This paper discusses the surveying operations, which involved climbing the pinnacle to collect Ground Control Points (GCPs) and using a UAV to capture aerial imagery. The photographs were processed using SfM software to generate point clouds, mesh, and texture, which were then used for rock mass discontinuity mapping. The study compares models of different qualities and point densities to determine the optimal trade-off between processing time and accuracy in terms of discontinuity mapping. The results show that higher quality models allow for more detailed mapping of discontinuities, with some drawbacks due to noise in the case of the densest solution (e.g., increase in frequency of outliers across the point cloud). These pros and cons are also discussed in relation to the computational cost necessary to build the models. The study also examines the limitations and challenges of performing discontinuity mapping in the different models, including subjectivity in interpretation. A further element of interest is the publication of a high-quality 3D georeferenced model of the "Campanile di Val Montanaia" to be used for several potential further applications, such as stability analyses and numerical modeling. [ABSTRACT FROM AUTHOR]

The paper illustrates the construction of abacuses for the semi-quantitative assessment of stratigraphic seismic amplification phenomena, applicable in the eastern Abruzzo region (central Italy). The abacuses provide three expected Amplification Factors (Fas): Fa0.1-0.5, Fa0.4-0.8, Fa0.7-1.1, performed as the ratio between the integral of output and input, in the mentioned time intervals, considering the acceleration response spectra. The choice derives from the fact that these parameters are better correlated to the response of the buildings, characterised by their own different periods. To prepare the abacuses, a procedure was adopted that took into consideration the geological analysis of the area, the collection of all the available geophysical and geotechnical data, the choice of the seismic inputs representative of the seismic hazard, the identification of the main seismic stratigraphic sequences and the numerical analysis aimed at evaluating the Fa. The abacus consists of a series of tables prepared in order to take account of the stratigraphic variability in the area, as a function of the basic seismic hazard level and the vibration period interval to calculate the Fa. By knowing the stratigraphic and mechanical characteristics of the site and using the abacuses, the values of the Fa are obtained. [ABSTRACT FROM AUTHOR]

This paper deals with precipitation events, particularly the problem of recognising events individually, of distinguishing one local meteorological/precipitation event from another. The final aim was to arrive at a more appropriate conceptualization of "distance" between individual annual events. A criterion for identifying annual precipitation events, inside a 5 min-timestep series of pluviometric data, was proposed. Using this numerical criterion, a series of annual distances between events were obtained and compared with those obtained by other two known and applied statistical methods. This comparison would be important for linking the so-called statistical methods to the real data of the series, analysed through a numerical process. This would make it possible to provide a kind of "measure" for the understanding of real data via a statistical model. Results showed that distances between events, obtained through numerical analyses, are almost always different from those obtained by statistical methods. The supposed Poisson-process, generally matched to, and widely applied in the field of rainfall data, showed some contradiction with the analysis conducted in this paper. The so-called Lag method shows a numerical method type distribution, but produces some important internal deviations from numerical results. It seems that the method proposed in this paper can reproduce the real distances between events more realistically compared to the statistical methods considered here. Exponential distribution does not seem highly performing, at least in the case of the annual analysis, with series of a 5-min time-step resolution, obtained from rain gauges installed in the Veneto Region of Italy. It is believed that the numerical criterion presented in this paper can be considered adequate for determining the distances between events, within an annual time-window. [ABSTRACT FROM AUTHOR]

Industrial single-storey buildings are the most diffuse typology of steel construction located in Italy. Most of these existing buildings were erected prior to the enforcement of adequate seismic provisions; hence, crucial attention is paid nowadays to the design of low-impact retrofit interventions which can restore a proper structural performance without interrupting productive activities. Within this framework, an existing industrial single-storey steel building located in Nusco (Italy) is selected in this paper as a case-study. The structure, which features moment resisting (MR) truss frames in both directions, is highly deformable and presents undersized MR bolted connections. Structural performance of the case-study was assessed by means of both global and local refined numerical analyses. As expected, the inadequate performance of connections, which fail due to brittle mechanisms, detrimentally affects the global response of the structure both in terms of lateral stiffness and resistance. This effect was accounted for in global analyses by means of properly calibrated non-linear links. Thus, both local and global retrofit interventions were designed and numerically investigated. Namely, lower chord connections were strengthened by means of rib stiffeners and additional rows of M20 10.9 bolts, whereas concentrically braced frames (CBFs) were placed on both directions' facades. Designed interventions proved to be effective for the full structural retrofitting against both seismic and wind actions without limiting building accessibility. [ABSTRACT FROM AUTHOR]

A hybrid seismic fragility model for territorial-scale seismic vulnerability assessment of masonry buildings is developed and presented in this paper. The method combines expert-judgment and mechanical approaches to derive typological fragility curves for Italian residential masonry building stock. The first classifies Italian masonry buildings in five different typological classes as function of age of construction, structural typology, and seismic behaviour and damaging of buildings observed following the most severe earthquakes occurred in Italy. The second, based on numerical analyses results conducted on building prototypes, provides all the parameters necessary for developing fragility functions. Peak-Ground Acceleration (PGA) at Ultimate Limit State attainable by each building's class has been chosen as an Intensity Measure to represent fragility curves: three types of curve have been developed, each referred to mean, maximum and minimum value of PGAs defined for each building class. To represent the expected damage scenario for increasing earthquake intensities, a correlation between PGAs and Mercalli-Cancani-Sieber macroseismic intensity scale has been used and the corresponding fragility curves developed. Results show that the proposed building's classes are representative of the Italian masonry building stock and that fragility curves are effective for predicting both seismic vulnerability and expected damage scenarios for seismic-prone areas. Finally, the fragility curves have been compared with empirical curves obtained through a macroseismic approach on Italian masonry buildings available in literature, underlining the differences between the methods. [ABSTRACT FROM AUTHOR]

The need for a reliable estimate of the actual failure probability of existing river embankments under changing boundary conditions represents an ever-demanding task for researchers and designers, and those involved in their maintenance and management. Uncertainty and variability of soil suction and water content spatial and temporal distributions, together with the definition of a suitable soil model that accounts for the partially saturated state of embankment materials, are among the most critical aspects to be possibly included in the advanced analysis and design of such linear earthen infrastructures. The use of specialist integrated monitoring can be here functional to enable calibration and to enhance reliability and consistency of predictive analyses. Site measurements of the main variables at relevant depths are typically rarely available, whereas an accurate soil characterization under partially saturated conditions is only performed in research applications, thus producing limited confidence on stability conditions. To provide a useful and innovative tool to evaluate realistic stability conditions of levees under transient flow conditions, a full-scale monitoring system has been implemented on an existing section of the River Secchia (northern Italy) 11-m-high flood defenses. The complementary use of specific laboratory tests, innovative field measurements and numerical analyses presented in the paper aims at providing a suitable methodological approach to the performance assessment of these vital geotechnical systems throughout their entire lifetime and highlighting possible limitations of typically used methods of analysis. [ABSTRACT FROM AUTHOR]

The preparation, initiation and occurrence dynamics of earthquakes in Italy are governed by several frequently unknown physical mechanisms and parameters. Understanding these mechanisms is crucial for developing new techniques and approaches for earthquake monitoring and hazard assessments. Here, we develop a first-order numerical model simulating quasi-static crustal interseismic loading, coseismic brittle episodic dislocation and post-seismic relaxation for extensional and compressional earthquakes in Italy based on a common framework of lithostatic and tectonic forces. Our model includes an upper crust, where the fault is locked, and a deep crust, where the fault experiences steady shear. The results indicate that during the interseismic phase, the contrasting behaviour between the upper locked fault segment and lower creeping fault segment generates a stretched volume at depth in the hangingwall via extensional tectonics while a contracted volume forms via compressional tectonics. The interseismic stress and strain gradients invert at the coseismic stage, with the interseismic dilated volume contracting during the coseismic stage, and vice versa. Moreover, interseismic stress gradients promote coseismic gravitational subsidence of the hangingwall for normal fault earthquakes and elastic uplift for reverse fault earthquakes. Finally, the post-seismic relaxation is characterized by further ground subsidence and uplift for normal and reverse faulting earthquakes, respectively, which is consistent with the faulting style. The fault is the passive feature, with slipping generating the seismic waves, whereas the energy activating the movement is stored mostly in the hangingwall volume. The main source of energy for normal faulting and thrust is provided by the lithostatic load and elastic load, respectively. [ABSTRACT FROM AUTHOR]

The Seismic Microzonation of level 3 (SM3) is nowadays a world-wide accepted tool for the mitigation of seismic risk. The SM3 is a complex process involving different disciplines ranging from Geology and Applied Seismology to Structural and Geotechnical Engineering. The outcome of a SM3 is presented on a zoning map in terms of a selected ground shaking intensity parameter and susceptibility to main ground instability (soil liquefaction, settlements, landslides, fault ruptures). In an advanced SM3 study for a given area, four main interdisciplinary steps can be recognized: (1) definition of the reference input motions, (2) construction of the subsoil model, (3) performing of numerical analyses and computing of amplification factors, (4) identification of zones with different geotechnical hazard potential and drawing up of the SM3 map. After the 2016–2017 Central Italy seismic sequence, intensive studies have been performed to obtain SM3 maps in 137 municipalities most damaged by the earthquakes. The aim of these studies has been to obtain a clear background on site effects to perform a correct reconstruction of the municipalities. In the paper, main results and critical issues of the above-mentioned steps of SM3 procedure are discussed together with some remarks on the use of SM3 output in supporting seismic design for reconstruction. [ABSTRACT FROM AUTHOR]

The paper presents the results of 5 case studies on complex site effects selected within the project for the level 3 seismic microzonation of several municipalities of Central Italy damaged by the 2016 seismic sequence. The case studies are characterized by different geological and morphological configurations: Monte San Martino is located along a hill slope, Montedinove and Arquata del Tronto villages are located at ridge top whereas Capitignano and Norcia lie in correspondence of sediment-filled valleys. Peculiarities of the sites are constituted by the presence of weathered/jointed rock mass, fault zone, shear wave velocity inversion, complex surface and buried morphologies. These factors make the definition of the subsoil model and the evaluation of the local response particularly complex and difficult to ascertain. For each site, after the discussion of the subsoil model, the results of site response numerical analyses are presented in terms of amplification factors and acceleration response spectra in selected points. The physical phenomena governing the site response have also been investigated at each site by comparing 1D and 2D numerical analyses. Implications are deduced for seismic microzonation studies in similar geological and morphological conditions. [ABSTRACT FROM AUTHOR]

This paper describes the results of a 2D and 3D numerical modeling carried out on an unstable natural rock slope (volume = 110,000–335,000 m3) located in north-eastern Italy (Friuli Venezia Giulia Region). It was aimed at investigating the mechanical behavior and internal rock mass damage of the unstable slope before the collapse. The numerical simulations testify that the stability condition of the slope is close to the limit equilibrium (strength reduction factor, SRF = 1.03–1.13), as demonstrated by the considerable rock mass damage observed on the field. The overall mechanical behavior of the slope is mainly governed by the kinematic conditions of the secondary internal blocks, which, in turn, depend on the geometry and mechanical properties of the major discontinuities that delimit the adjacent blocks. Slope failure is achieved through internal rock mass damage represented by internal shear and tensile ruptures localized in correspondence with over-stressed zones. The failure mechanism is characterized by sliding along pre-existing discontinuities and inner damage in the form of the enucleation of shear bands that originate internal secondary failure surfaces and/or damaged rock mass zones. The stress–strain modeling predicts intense slope deformations in zones where rock mass damage actually occurred. This paper emphasizes the decisive connection between the geomechanical field survey and numerical modeling. The comparison of surface geological data acquired on the field with the mechanical indicators obtained from the numerical analyses can significantly improve knowledge of the rock mass damage process that involves unstable slopes approaching failure condition. [ABSTRACT FROM AUTHOR]

This paper presents the results of numerical analyses of ground motion in the Red Zone sector of Amatrice hill, violently struck by the 2016–2017 Central Italy seismic sequence. The methodologies used in processing the data to define the numerical model are firstly described. The results obtained from the computational analyses are then presented and discussed by comparing them with experimental data set of weak motion recordings. Computational analyses were performed via both a 2D-numerical FEM model and a pseudo-three-dimensional hybrid model (SiSeRHMap) which develops multispectral maps taking into account topographic effects. Starting from available geological data and geophysical measurements, an original and specific subsoil GIS model was developed and utilised to perform the computational analyses. The preliminary map for fundamental periods computed from the subsoil model is in good agreement with the experimental data. A restricted set of weak ground motions acquired from an accelerometric station located in a reference site was used as input for the numerical analyses, while the signals of the corresponding events recorded at the top of the hill were used as targets in the reliability evaluation analysis of the outputs. In the area of Amatrice hill, which is characterized by a complex geological and topographical context, the reliability analysis shows a good performance of the hybrid model compared to the 2D-FEM model in the prediction of seismic response. Agreement generally was also good with regards to the experimental and computational results, both in relation to the amplitude and to the shape of the spectral amplification that change depending on the hill sector. Considering the predictive reliability of the models, a high amplification, due to topographic effects, was observed for the Red Zone by performing a back-simulation of the 24th August 2016 main shock. The analysis results highlight also that the maximum amplification factors, based on the definition of the Housner intensity, occur in the interval of periods 0–0.5 s covering the fundamental period range of the buildings in this area. [ABSTRACT FROM AUTHOR]

This work is aimed at the numerical interpretation of the evolution of damage and collapses observed on the Civic Tower of Amatrice, caused by the main events of the seismic sequence of 2016 in the Apennine area of Central Italy. In particular, the study considers the response of the tower with reference to the two main events, occurred on August 24th and October 30th, 2016 respectively. Non-linear dynamic analyses were carried out by developing a finite element model and the behaviour of the tower was investigated with reference to the damage and partial collapses produced by the main events. In dynamic numerical analyses, the accelerograms corresponding to the main seismic events obtained with the study of the site effects were used as seismic input. Moreover, studies have been carried out to understand if and which of the interventions of reinforcement/seismic improvement, realized at the beginning of the years '80, have been determinant to limit the damage, avoiding the complete collapse of the tower. The results of the study, on the one hand, allow to highlight a good correspondence between the evolution of the actual damage observed on the tower and the damage assessed by numerical analyses thus demonstrating the validity of the numerical models set up for the analyses. On the other hand, however, they have made it possible to underline how the presence of the improved material and structural reinforcement interventions carried out at the beginning of the years '80 have contributed to avoid the complete collapse of the tower. [ABSTRACT FROM AUTHOR]

The dynamic behaviour and the seismic vulnerability of the ancient civic clock tower of Amatrice, dramatically damaged by the last shocks sequence of 2016 that occurred in Central Italy, is studied in this paper by means of advanced 3D numerical analyses with the Non-Smooth Contact Dynamics Method (NSCD). Thus, a discontinuous approach was used to assess the dynamic properties and the vulnerability of the masonry structure, through large displacements regulated by the Signorini’s law, concerning the impenetrability between the rigid bodies, and by the Coulomb’s law, regarding the dry-friction model. Afterward, different values were assigned to the friction coefficient of the models and real seismic shocks were then applied in nonlinear analyses. The major purpose of this study is to highlight that relevant data on the real structural behaviour of historical masonry may provided through advanced numerical analyses. The comparison between the results of numerical simulation and survey of the existing crack pattern of the bell tower permitted to validate the selected approach. Finally, from results and conclusions provided by this case study, it is possible to affirm that the used methodology may be applied to a wide variety of historical masonry structure in Europe. [ABSTRACT FROM AUTHOR]

In this paper, an optimization model is defined for the design of a smart energy infrastructure integrating different technologies to satisfy the electrical demand of a given site. The considered smart energy infrastructure includes a photovoltaic plant, electrical storage systems, electric vehicles (EVs), and charging stations. The objective function of the optimization model considers the costs related to the installation and maintenance of the considered technologies, as well as the costs associated with the energy exchanges with the external grid. A very extensive numerical analysis is reported in the paper, referred to a test case in a real site in Liguria Region, in the north of Italy. Many scenarios are analyzed and discussed, with specific attention to evaluate the role of electric mobility within a smart energy infrastructure and a focus on EVs acting as mobile storage systems. [ABSTRACT FROM AUTHOR]

Abstract Multiple self-potential (SP) anomalies are analyzed by using a Genetic-Price Algorithm (GPA), which has been recently introduced for the inversion of SP data. The proposed approach is tested on multiple synthetic anomalies, which are modeled by horizontal cylinders. First, a forward modeling is used to analyze the resolution of such anomalies by varying all model parameters. Then, GPA is applied to invert synthetic multiple SP anomalies. The numerical analyses show that the proposed approach is able to fully characterize the anomaly sources by providing the correct values of the model parameters as well as the number of sources, even if Gaussian random noise is added to the synthetic data. Furthermore, to show the computational efficiency of GPA, the results of a comparative analysis with the Very Fast Simulated Annealing algorithm are given. The validity of the GPA approach is confirmed by its application to three examples of self-potential field data from mineral exploration and groundwater investigations, which are presented and discussed in relation to other inversion approaches. Finally, the quantitative interpretation of multiple anomalies along a SP profile crossing the Mt. Somma-Vesuvius volcano caldera (southern Italy) is provided. Highlights • A global optimization algorithm is applied for multiple SP anomaly interpretation. • The effectiveness of the proposed approach is tested on synthetic SP data. • Applications of the algorithm to field anomalies of multiple sources are presented. • The algorithm is shown to be competitive with PSO and VFSA optimization methods. [ABSTRACT FROM AUTHOR]

In this paper, we address the issue of evaluating the seismic site response for sites located on large alluvial plains, for which no reference sites can be identified, but some earthquakes can be simultaneously recorded at both surface and depth. In the proposed method, surface and borehole records are firstly used to assess the local 1D velocity model, then a model representing a virtual reference rock site is defined, and finally the site spectral amplification is calculated through numerical modeling. The effectiveness of the method is demonstrated at the site of Mirandola (Italy). This site is located in an area which suffered heavy damage during the seismic sequence that started in Northern Italy with the Mw = 5.8 event on May 20th, 2012. That time, the site hosted an accelerometer of the National Accelerometric Network, which recorded the whole sequence. A new station, named MIRB (MIRandola Borehole), was installed during 2014; it is equipped with three accelerometric sensors deployed at surface, 31 and 126 m depth, respectively. The results of this study evidence that Mirandola is characterized by an amplification level consistent with that of a class-C soil for up to a period of about 0.45 s, while for higher periods, the amplification lays between class-B and C soils. [ABSTRACT FROM AUTHOR]

Stimulated by the recent advances in computational tools for the simulation of seismic wave propagation problems in realistic geological configurations, this paper presents a 3D physicsbased numerical analysis of near-source ground motion during the MW 6.0 2012 May 29 earthquake in the Po Plain, Northern Italy. To reproduce with sufficient accuracy some of the most peculiar features of the near-source strong-motion records and of the spatial variability of damage distribution, this study required a sequence of investigations, starting from the analysis of a wide set of near-source records, to the calibration of an improved kinematic seismic source model, up to the development of a 3D numerical model of the portion of the Po Plain interested by the earthquake. The latter includes the basin geometry, characterized by sediment thickness sharply varying from few tens of metres to some kilometres. The spatial resolution of the numerical model is suitable to propagate frequencies up to about 1.5 Hz. Numerical simulations were performed using the open-source high-performance code SPEED, based on the Discontinuous Galerkin Spectral Elements method. The 3D numerical model, coupled with the updated slip distribution along the rupturing fault, proved successful to reproduce with good agreement, measured through quantitative goodness-of-fit criteria, the most relevant features of the observed ground motion. These include: (i) the large fault normal velocity peaks at the near-source stations driven by updip directivity effects; (ii) the small-scale variability at short distance from the source, resulting in the out-of-phase motion at stations separated by only 3 km distance; (iii) the propagation of prominent trains of surface waves, especially in the Northern direction; (iv) the map of earthquake-induced ground uplift with maximum values of about 10 cm, in substantial agreement with geodetic measurements and (v) the two-lobed pattern of the peak ground velocity map, well correlated with the distribution of macroseismic intensity. [ABSTRACT FROM AUTHOR]

Mt. Vesuvius is one of the most studied volcanoes in the world and its proximity to an extremely populated area makes it also one of the most threatening. Violent Strombolian (VS) events have occurred in the most recent history of the volcano, and they are the type most likely to occur in case of reactivation of the volcano in the near future. In order to investigate the dynamics and hazard of this type of eruption, we performed new field and laboratory work and numerical simulations of plume dynamics, fallout and tephra dispersal associated with such eruptions. Attention was specifically focused on the 1906 eruption, a recent and well-studied VS event. Based on new field analyses and historical observations, we reconstructed the temporal evolution of eruption source conditions during the event. The reconstructed explosive phase of the eruption is inferred to have been 8 days long and characterized by two distinct stages: a former short and intense period with sustained convective plume fed by powerful lava fountains (20 h) followed by a prolonged and less intense period of ash emission (172 h). The total grain-size distributions for both phases, used as inputs to the model, were obtained by field work and laboratory analyses. Based on these new volcanological data and reconstruction of wind field direction and intensity, partially derived from historical sources, the 1906 event was numerically simulated and results compared to deposit distributions. The modelling outcomes for the ash emission phase provide a better agreement with the measured tephra mass load for a simulation run in which ash aggregation (described by the models of Cornell et al. J Volcanol Geotherm Res 17:89-109, , and Biass et al. Nat Hazard Earth Syst Sci 14:2265-2287, ) is specifically taken into account, confirming the importance of this process during tephra dispersal. The aggregation model that best fits the simulated results to the measured ground loadings has 80 % of particles Φ ≥ 4 that aggregate uniformly in the range Φ = −1 to 3. Two additional simulations of a VS event were carried out by using meteorological data of two specific periods to exemplify weather's potential on impacts of such eruptions, particularly tephra loading, on the surrounding areas. The model outcomes clearly highlight the major effects of differences in local meteorology on plume dynamics and ash dispersal and the key role of wind shear in determining the cumulative thickness of ground deposits. Results also show that, due to the long duration of this kind of eruption and the large variability in zonal winds at this latitude, ash dispersal and fallout from VS events at Vesuvius represent a probable hazard for all of the territory near Vesuvius, including the city of Naples, where cumulative tephra loadings might reach critical thresholds for roof collapse and infrastructure damage. [ABSTRACT FROM AUTHOR]

Among the several Triassic carbonate platforms of the Dolomites, the high and vertical cliff of the Gusela del Nuvolau Cassian carbonate platform provides one of the best exposures of a platform - basin transition. However, its analysis using traditional filed surveys can often be limited and distorted due to the difficult and often impossible accessibility of its walls and the lack of optimal observation points. For this reason, in this study an analysis based on the Digital Outcrop Model (DOM) developed by Uncrafted Aerial Vehicle (UAV) digital photogrammetry technique was used. The 3D DOM analysis allowed to properly determine the stratal geometry and the fracture network of the carbonate platform and underlying basinal deposits (San Cassiano Formation) and to identify the presence of early deformation structures. These structures were probably driven by the differential compaction of the basinal facies that is due the differential load of the carbonate platform as confirmed by the numerical 2D models. These structures are generally orthogonal to the NE progradation direction of the carbonate platform, as in the nearby Lastoni di Formin platform. • the UAV photogrammetry allows to overcome the limitations of traditional surveys and terrestrial remote sensing techniques. • 3D DOM analysis and 2D numerical models suggest the presence of differential compaction driven early deformation structures. • 3 fracture sets trending NW, NNW and NE affect the Nuvolau platform. Some NW structures are normal synsedimentary faults. • the NE progradation of the platform is approximately orthogonal to the early deformation faults and fractures. [ABSTRACT FROM AUTHOR]

This paper outlines the response of the healthcare system in the area mainly affected by the 2012 Emilia earthquake by drawing on specific surveys and information from local health authorities. Some hospitals were evacuated after the M $$_\mathrm{l}$$ = 5.8 May 20 seismic event due to damage to non structural components and minor structural damage. A short description of the damage suffered and characteristics of the healthcare system as a whole is offered initially, followed by a detailed description of the effects which took place at the Santa Maria Bianca hospital of Mirandola. The focus has been on damage to non structural elements and content, whose integrity is of primary importance for healthcare structures performance during and after a seismic event. Some instruments for the acquisition of accelerometric data were installed after the May 20 event both outside and inside a building which is part of the hospital complex. The seismic behavior of this building has also been analysed by means of a purposely made finite element model and on the basis of the recorded data. The contribution of undamaged and damaged masonry infills to the global seismic response has also been estimated thus providing some hints on the observed building performance. [ABSTRACT FROM AUTHOR]

Highlights: [•] A clock tower collapsed during the 2012 Emilia Romagna (Italy) seismic sequence is analyzed. [•] A full 3D Finite Element model obtained after a detailed historical/geometrical analysis is used. [•] Pushover, limit analyses under horizontal loads and full non-linear dynamic analyses are conducted. [•] All approaches confirm the high vulnerability of the structure and the observed collapse modes. [•] The aim of the numerical analyses is to provide detailed information for the reconstruction. [Copyright &y& Elsevier]

The earthquake-induced damage to earth-retaining structures located along roadway network clearly affects the operations during the emergency and rescue phases in the immediate aftermath of a seismic event. The prompt estimation of the seismic vulnerability of a structure or a typological class of structures having a similar seismic behaviour is of foremost importance. In this framework, fragility curves represent an effective tool which can be adopted for quickly evaluating the seismic response of strategic structures. Aim of this study is to propose novel sets of fragility functions for earth-retaining structures, which adopt as input the Intensity Measures (IMs) best correlated to the response of the walls. First, target earth-retaining structures identified along the Italian roadway network are numerically modelled and then two-dimensional (2D) dynamic analyses carried out with reference to different geometrical features of the structure (i.e. height and shape of the walls) and configurations of the backfill. Metrics such as efficiency, practicality, proficiency, and sufficiency are assessed for different demand parameters (overall 35 IMs). The structure response is expressed in terms of horizontal displacement and rotation of the wall. Fragility functions for peak values of velocity (PGV) and acceleration (PGA) are developed. The fragility models are then applied for computing the seismic damage scenario associated to a real earthquake occurred in Central Italy in 2016. Predictive capabilities of the models are assessed by comparing surveyed damages. The proposed tools are useful in emergency management and also during preparedness phase to identify the priority actions and proper countermeasures for seismic risk mitigation. • 2D dynamic analyses of earth-retaining walls along the Italian roadway network. • Identification of the optimal intensity measures. • Development of novel fragility curves for earth-retaining walls. • Computation of seismic damage scenario associated to a real earthquake. [ABSTRACT FROM AUTHOR]

Historical sources report that Rome has experienced considerable earthquake ground motion in the past, even though it is quite far from high-magnitude seismogenic sources. Damage distribution seems to be predominantly controlled by ground shaking amplification related to local soil conditions. In this context a multidisciplinary research project has been conducted to determine the seismic microzonation of the Central Archaeological Area of Rome, which includes the Palatine Hill, Roman Forum, and Coliseum. In particular, the present paper details the results of one and bi-dimensional site response analyses carried out within this project, focusing discussion on representative cross-sections. The peculiarity of this work stems from the fact that it represents the first systematic study on the seismic site response of Rome's historical centre based on a robust subsoil model which integrates a large amount of available and original geological, geophysical and geotechnical data. Investigation of the physical phenomena responsible for site effects shows that ground motion distribution is mainly controlled by 1D resonance phenomena and 2D effects associated with soft alluvial valleys bordering the Palatine Hill, a deep paleo-valley and, to a lesser extent, topography and the morphology of anthropogenic deposits. The analyses show maximum amplification factors, defined in terms of Housner Intensity, as high as 1.4-1.8 over the period range of 0.1-1.0 s. Such values can be significantly relevant for the monumental and archaeological heritage of this area, as many are highly vulnerable due to their great age. [ABSTRACT FROM AUTHOR]

• A complete characterization of "Scaglia Rossa" masonry is carried out. • The considered masonry monopolized constructions between 1950 and 60s in Central Italy. • Widespread damages and collapses were observed in the 2016 Central Italy earthquake. • Uniaxial compression, bending and shear-compression tests are performed on stone, mortar and walls. • The first quantitative indications were provided, filling a void in current bibliography. This paper outlines the complete characterization of masonry walls composed of "Scaglia Rossa", a typical stone of the Apennine area between the Umbria and Marche Regions in Central Italy. The study focuses the assessment of the mechanical behavior by means of an experimental campaign carried out in the laboratory of the Polytechnic University of Marche, where the samples of "Scaglia Rossa" masonry, obtained from the controlled demolition of three school buildings, were reconstructed with the same techniques of the 1950s-'60s, and then tested in order to identify both the constituent materials, stone and mortar, and the composite masonry. The experimental tests were prior to a numerical analysis implemented by the adoption of a nonlinear model capturing the cracking behavior. The main mechanical parameters were then calibrated by means of an optimization algorithm of Levenberg-Marquardt, considering a continuous approach with both (i) macro- and (ii) micro-modelling techniques and obtaining resistance parameters not deriving directly from the experimental tests. The comparison between the results obtained from the Levenberg - Marquardt algorithm by changing the parameters of the damage model based on data given by the experimental campaign allowed to confirm the validity of the approach used. [ABSTRACT FROM AUTHOR]

This study is motivated by the amplified transmission rates of the SAR-CoV-2 virus in areas with high concentrations of fine particulates (PM 2.5) as reported in northern Italy and Mexico. To develop a deeper understanding of the contribution of PM 2.5 in the propagation of the SAR-CoV-2 virus in the population, the deposition patterns and efficiencies (DEs) of PM 2.5 laced with the virus in healthy and asthmatic airways are studied. Physiologically correct 3-D models for generations 10–12 of the human airways are applied to carry out a numerical analysis of two-phase flow for full breathing cycles. Two concentrations of PM 2.5 are applied for the simulation, i.e., 30 μg⋅m−3 and 80 μg⋅m−3 for three breathing statuses, i.e., rest, light exercise, and moderate activity. All the PM 2.5 injected into the control volume is assumed to be 100% contaminated with the SAR-CoV-2 virus. Skewed air-flow phenomena at the bifurcations are proportional to the Reynolds number at the inlet, and their intensity in the asthmatic airway exceeded that of the healthy one. Upon exhalation, two peak air-flow vectors from daughter branches combine to form one big vector in the parent generation. Asthmatic airway models has higher deposition efficiencies (DEs) for contaminated PM 2.5 as compared to the healthy one. Higher DEs arise in the asthmatic airway model due to complex secondary flows which increase the impaction of contaminated PM 2.5 on airways' walls. [Display omitted] • Deposition of PM 2.5 laced with the virus in healthy and asthmatic airways was studied. • 3-D models for generations 10–12 of the human airways were applied. • Two concentrations of PM 2.5 of 30 and 80 μg⋅m−3 were applied for the simulation. • Asthmatic airways had higher deposition for contaminated PM 2.5 than healthy ones. • Higher DEs in asthmatic airways were due to complex secondary flows. [ABSTRACT FROM AUTHOR]

The present research paper properly focuses on the dynamics and failure mechanisms of the masonry "Apennine Church" of Santissimo Crocifisso in Pretare, municipality of Arquata del Tronto in the province of Ascoli Piceno (Marche region, Central Italy). Such a peculiar structural type traditionally characterizes the intense seismic area of Central Italy, unfortunately almost totally damaged by the recent shock sequence of 2016. Advanced numerical modeling through discontinuous and continuous approaches were here utilized to have an insight into the dynamic properties and behavior of the structure under strong nonlinear dynamic excitations. In the discrete element approach, the non-smooth contact dynamics method, implemented in LMGC90©, was applied, adopting a full 3D detailed discretization. The church was schematized as an arrangement of rigid blocks, subjected to sliding by friction and perfect plastic collisions, with a null restitution coefficient. In the finite element approach, the concrete damaged plasticity model available in Midas FEA NX© was involved. This model allows reproducing the tensile cracking, the compressive crushing, and the degradation of the material under cyclic loads. Finally, the numerical analyses provided a valuable picture of the actual behavior of the church, thus giving useful hints for future strengthening interventions. [ABSTRACT FROM AUTHOR]

• Aging problem for a wall package with vacuum insulation panels is studied. • Measures of heat flux and temperatures for 5 years are compared. • Experimental and analytical elaborations are combined for finding the aging trend. • The aging curve is implemented in a case study by means of dynamic simulation tool. • Energy consumptions, environmental indices and cost savings are discussed. The lack of data on the aging rate, under real operating conditions, is one of the most critical aspects for the diffusion of vacuum insulation panels in the building sector. This problem is analyzed in this paper by means of an integrated experimental-numerical approach. The panels under investigation are characterized by micro-porous silica pressed powder core with an aluminum barrier layer, for a total thickness of 10 mm. These are the insulation layer of a wall made of autoclaved aerated concrete blocks (total thickness of 21 cm) placed in a test room located in Benevento (south Italy). The experimental analysis is focused on the monitoring of heat flux and temperatures in order to evaluate the performance by means of the comparison with the same wall without insulation and for the indirect determination of the aging after five years (2015–2020). Results indicate an increment of thermal conductivity of 10.6%. Moreover, basing on experimental data, a semi-empirical linear function is appropriate to approximate the aging trend. A numerical case study, that implement the obtained aging trend, shows that the increment of thermal conductivity of vacuum insulation panels brings a reduction of the expected energy saving of 3% after 15 years. This result is true for several European cities with heating dominated climates. [ABSTRACT FROM AUTHOR]

• An ASHP coupled with an EAHX system is proposed and modelled. • The ASHP- EAHX behaviour is tested in four locations with different climates. • The model has been validated with a real case. • The ASHP- EAHX allows to use ASHP also with lower external temperatures. • For cold extremely climate, the reduction of the shutdown periods of ASHP. Geothermal energy has a huge potential in building applications. This paper proposes the use of an Air-Source Heat Pump (ASHP) system coupled with a Horizontal Earth-To-Air Heat Exchanger (EAHX) to reduce energy consumption in buildings. The novelty is to geothermally pre-heat or pre-cool the air source of the ASHP through the EAHX, reducing the electric power needed, keeping constant heating/cooling capacity. The behaviour of ASHP-EAHX system has been investigated by a numerical model implemented in TRNSYS. A total of 54 combinations have been obtained and tested varying ground thermal properties, burial depth, air flow rate and pipe length. The model has been validated with a real case showing a good agreement between simulated and monitored data. The study is focused on the city of Turin (North of Italy), compared with Brindisi (South of Italy), and extremely cold and hot climates like Tromsø (Norway) and Béchar (Algeria), respectively. The ASHP-EAXH performance has been investigated, by the comparison with the traditional ASHP, using different coefficients, such as the Coefficient of Performance (COP), the Energy Efficiency Ratio (EER), the Seasonal Coefficient of Performance (SCOP), and the Seasonal Energy Efficiency Ratio (SEER). The paper reveals how the ASHP-EAHX system show higher performance compared to the traditional ASHP, in all seasons. The overall merit is, for cold extremely climate, the reduction of the shutdown periods, when the outside temperature is below the limit operating temperature, and to allow the extension of the use of the heat pump to locations, where it is currently not convenient for the average outside temperature lower than the limit operating temperature of the heat pump. [ABSTRACT FROM AUTHOR]

In this study, the sustainability of low-temperature geothermal field exploitation in a carbonate reservoir near Mondragone (CE), Southern Italy, is analyzed. The Mondragone geothermal field has been extensively studied through the research project VIGOR (Valutazione del potenzIale Geotermico delle RegiOni della convergenza). From seismic, geo-electric, hydro-chemical and groundwater data, obtained through the experimental campaigns carried out, physiochemical features of the aquifers and characteristics of the reservoir have been determined. Within this project, a well-doublet open-loop district heating plant has been designed to feed two public schools in Mondragone town. The sustainability of this geothermal application is analyzed in this study. A new exploration well (about 300 m deep) is considered to obtain further stratigraphic and structural information about the reservoir. Using the derived hydrogeological model of the area, a numerical analysis of geothermal exploitation was carried out to assess the thermal perturbation of the reservoir and the sustainability of its exploitation. The effect of extraction and reinjection of fluids on the reservoir was evaluated for 60 years of the plant activity. The results are fundamental to develop a sustainable geothermal heat plant and represent a real case study for the exploitation of similar carbonate reservoir geothermal resources. [ABSTRACT FROM AUTHOR]

• A tool to detect spatio-temporal landslide-induced effects on buildings is presented. • Building performace is investigated by DInSAR and structural analyses. • Pre- and post-repair intervention is analyzed by DInSAR time-series. Slow-moving landslides are a natural hazard which affects wide areas in the world and often are cause of significant damage to structures and infrastructures. Analysis of landslide evolution and of their interaction with existing man-made structures plays a key role in risk prevention and mitigation activities. To this purpose, a considerable interest towards innovative approaches has grown among the scientific community and land management institutions. In this work, Synthetic Aperture Radar data acquired by C-band and X-band sensors, combined with numerical analyses, have been successfully applied as a tool to detect spatial and temporal landslide-induced effects, in terms of deformations and structural behavior of a building affected by ground instability. Such approach has been applied to Moio della Civitella urban settlement (Salerno province, Italy), whose whole territory is interested by several slow-moving landslides. In detail, performance of a masonry building aggregate and the efficacy of restoration works have been investigated through an integrated assessment of displacement time-series pre- and post-repair intervention, and structural analysis performed with numerical code. Historical DInSAR data have permitted firstly the interpretation of building displacement time-series corresponding to pre- and post-works configurations; subsequently, the analysis of interpolated interferometric products has allowed to define gradient maps of vertical and horizontal displacements and to identify part of aggregate which can suffer a greater susceptibility to damage as a consequence of deformation gradients. Finally, the comparison of satellite and numerical data showed a substantial agreement with local failures and damage surveyed, thus confirming the capability of DInSAR technique to investigate building performance where no in situ displacement measurements were available. [ABSTRACT FROM AUTHOR]

Based on critical examination of both fresh and dried specimens and a morphometric analysis of herbarium specimens we performed a comparative study of the three closely related Gastridium (Poaceae, Tribe: Poeae, Subtribe: Agrostidinae) species G. ventricosum, G. phleoides and G. scabrum collected in Italy. The study aimed to provide new diagnostic tools to improve the taxonomy of the genus and confirm species delimitation. Variation in floral morphology in the three species was explored using seven quantitative and ten qualitative characters measured on 318 spikelets, both awned and unawned. Statistical methods, including principal components analysis (PCA) and non‐metric multidimensional scaling (NMDS), were used. Numerical analyses showed a general distinctness of spikelets and florets, consistent with the three studied species, and revealed among and within species variation patterns in both spikelet types. Accordingly, the most informative quantitative characters appeared to be the width and length of glumes and the length of awns, useful to distinguish G. phleoides which has the narrowest glumes and longer awns than the other species, while G. scabrum has the widest glumes. The most informative qualitative characters appeared to be the presence/absence of thick hairs or minute tubercles on the upper side of the lemma. The autonomy of the three studied species was confirmed. The taxonomic significance of the results is briefly discussed, and notes on the species distribution are included. Some nomenclatural and taxonomic notes on G. scabrum, of which literature still showed evidence of a general unawareness, are provided. [ABSTRACT FROM AUTHOR]

During recent years, the availability of innovative monitoring instrumentation has been a fundamental component in the development of efficient and reliable early warning systems (EWS). In fact, the potential to achieve high sampling frequencies, together with automatic data transmission and elaboration are key features for a near-real time approach. This paper presents a case study located in Central Italy, where the realization of an important state route required a series of preliminary surveys. The monitoring system installed on site included manual inclinometers, automatic modular underground monitoring system (MUMS) inclinometers, piezometers, and geognostic surveys. In particular, data recorded by innovative instrumentation allowed for the detection of major slope displacements that ultimately led to the landslide collapse. The implementation of advanced tools, featuring remote and automatic procedures for data sampling and elaboration, played a key role in the critical event identification and prediction. In fact, thanks to displacement data recorded by the MUMS inclinometer, it was possible to forecast the slope failure that was later confirmed during the following site inspection. Additionally, a numerical analysis was performed to better understand the mechanical behavior of the slope, back-analyze the monitored event, and to assess the stability conditions of the area of interest. [ABSTRACT FROM AUTHOR]

Renewable energy sources, especially wind power, have become a focus of energy policies in several countries around the world. Wind turbines have to be located on sites with high wind speeds, this leads to high forces acting upon the tower and the blades, causing vibrations throughout the structure. Current technical and scientific literature specifically focusses on vibrations of the wind turbine blades and the effect of earthquakes on the turbines. Additionally, there is considerable research in the field of low frequency noise and infrasound from wind turbines. This study presents the preliminary results retrieved from the analyses performed on real accelerometric time-histories recorded on a cracking wind-turbine located in southern Italy. The permanent accelerometric monitoring system has been installed in 2016, and it is recording data every day under several climatic conditions. Particularly, both weak- and strong-motion synchronized data are available from two three-directional stations: the first one, installed on the foundation and, the second one, installed on the top of the tower. In this phase of the study the recorded motion of the monitored tower has been investigated under several wind conditions correlating the dynamic characteristics of the structural eigenfrequencies with others parameters such as wind speed, air temperature, etc. Accelerometric data have been analysed using both stationary and non-stationary tools, particularly, weak-motion data have been analysed using Fourier Transform and Transfer Functions, while, strong-motion data have been analysed using the Stockwell Transform. In order to analyse the cracking phenomena observed at the base of the tower, also numerical analyses are in progress with the aim to evaluate stresses and strains associated to the complex thermo-mechanical behaviour of materials constituting the monitored tower and any fatigue phenomena. [ABSTRACT FROM AUTHOR]