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This paper focuses on seismic fragility and damage scenario assessment of minor Italian historical centres through the development of urban fragility curves. With reference to the case study of Balvano, a small centre located in Basilicata Region of Italy, two hybrid models have been adopted. The first is a mechanic-based hybrid model developed by the authors to derive urban fragility curves specifically; the second is the macroseismic method, originally conceived to derive typological fragility curves for single building classes, expanded to derive urban fragility curve herein. Balvano was strongly struck by 1980 Irpinia-Basilicata earthquake (Ms = 6.90) and hence subjected to an intense reconstruction process during 1980s, where almost the 80% of the buildings were reconstructed with reinforced concrete structures in the place of unreinforced masonry ones. Seismic vulnerability and damage scenarios before and after 1980 have been assessed and compared with the purpose of validating the effectiveness of the urban scale fragility curves obtained through hybrid methodologies and quantifying the effect of the 'new' seismic hazard maps and first seismic codes and recommendations released by the Italian Government in the aftermath of 1980 for the construction of new buildings or for retrofitting the existing ones. A good matching between predicted and occurred damage scenario from the research outcomes emerged, confirming the effectiveness of the urban scale hybrid fragility curves to assess seismic vulnerability at urban scale. Moreover, the comparison of the damage scenarios pre and post-reconstruction highlighted the crucial role played by the code prescriptions adopted in that years for reducing the seismic vulnerability of the municipality and the importance of the 'new' seismic hazard maps introduced in 1980s. Finally, the differences between mechanical-based hybrid and macroseismic model have been discussed in the paper. [ABSTRACT FROM AUTHOR]

The Department of Civil Protection (DPC), in compliance with the EU decision 1313/2013 and at the request of the Sendai Framework for Disaster Risk Reduction 2015–2030 to update the disaster risk assessments by various countries, released the latest National Risk Assessment for Italy at the end of 2018. Specifically, as regards the seismic risk assessment, six research units belonging to two centres of competence of the DPC collaborated under its guidance to update the risk maps of the Italian residential heritage. This extensive collaboration complied with the recent Italian code for Civil Protection, which requires a broad scientific consensus for risk assessment. During this research activity, six fragility models were developed, according to some common criteria (four for masonry buildings and two for RC buildings). These models were then implemented by the DPC for the definition of the national seismic risk. Within this context, the aim of this paper is to evaluate the risk results provided by these models, compare their features, and assess and validate their prediction capabilities. In particular, this paper shows the comparison of predicted and observed damage scenarios and consequences on building stock and the population of two seismic events, i.e. L'Aquila 2009 and Amatrice 2016. Furthermore, the paper provides some interesting damage and risk predictions at a national level. Overall, the forecasts and comparisons made in this study demonstrate the validity of the approach adopted by the DPC for the assessment of national seismic risk. [ABSTRACT FROM AUTHOR]

The paper presents a mechanical-based framework for the evaluation of local-scale seismic fragility curves. The approach is oriented to a seismic vulnerability assessment of unreinforced masonry buildings and makes use of basic exposure data easily obtained from survey or available in existing database. An efficient finite element model and static nonlinear analyses are employed to assess the structural behaviour. The mechanical-based fragility curves are evaluated using Monte Carlo simulations that allow to account for the uncertainties propagation. The proposed approach is tested on a case-study regarding the city centre of Cosenza, in southern Italy, using exposure information available from CARTIS database. [ABSTRACT FROM AUTHOR]

This paper presents the path of knowledge developed for assessing the structural safety of the Norman-age Pisan Tower, which is mostly incorporated into the Royal Palace in Palermo, Italy. Historical, geomatic, and mechanical investigations were conducted and the most relevant results are herein collected and presented. The research path was addressed to specific tasks: identification of the building, geometric surveys, recognition of the sequence of phases of building transformation, detection of the components of the load-bearing structure, structural diagnostic surveys, and investigation of the subsoil and foundations. The explicit vulnerabilities found were mostly confined to the Piazzi library floor, while implicit vulnerabilities were identified in the presence of false walls and in high loads and fillings on the vaults of the last levels. The results of the analyses allowed the individuation of the confidence factors to use in structural analysis models aimed at the assessment of the seismic safety of the building. [ABSTRACT FROM AUTHOR]

This paper illustrates the derivation of an empirical fragility model for residential unreinforced masonry (URM) buildings, calibrated on Italian post-earthquake damage data and compatible with the key features of the Italian national seismic risk platform. Seismic vulnerability is described by fragility functions for three vulnerability classes, then refined based on the building height. To this aim, a clustering strategy is implemented to merge predefined building typologies into vulnerability classes, based on the similarity of the observed seismic fragility. On the other side, a specific procedure is built up to determine the vulnerability composition of the exposed URM building stock, starting from national census data. The empirically-derived model was implemented into the national seismic risk platform and used, together with other vulnerability models, for assessing seismic risk in Italy. The results presented in this paper, consisting of refined typological fragility curves and fragility curves for vulnerability classes, can be also exploited for estimating both expected seismic damage and risk in sites with similar seismic hazard and building inventory. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Post-earthquake reconstruction activities need tools for assessing the vulnerability of structures, based on visual inspection and quick survey. So far, the public administrations in charge of granting the funds and monitoring reconstruction have adopted different methods taken from scientific literature or developed ad hoc for specific events. The time is ripe for a standard method to be developed, treasuring from the lessons learned in the field. This paper proposes an expeditious tool based on visual survey for the assessment of the seismic vulnerability of unreinforced masonry buildings, starting from available methods, whose parameters were reassessed and recalibrated, and scientific evidence from recent literature. The influence of the main structural features was considered to calculate a vulnerability index in the 0–100 range. The effects of materials and arrangement of masonry were quantitatively evaluated through the masonry quality index, which represents an advancement with respect to current practice. The method was validated on a sample of 50 masonry aggregates and nearly 200 structural units of L'Aquila, Italy, where reconstruction is underway after a destructive earthquake in 2009. The sample is representative of the built heritage of other earthquake prone areas in Italy and many European Countries and the proposed method is a step forward the development of a standard tool to be used in future post-earthquake reconstruction scenarios. [ABSTRACT FROM AUTHOR]

Seismic upgrading and retrofitting of existing constructions is a pressing need for designers and researchers. The necessity of efficient seismic upgrading/retrofitting techniques is, therefore, required in seismic-prone countries, such as Italy. In this framework, steelwork has clearly shown many advantageous applications in the last century. Nonetheless, if compared to other different technologies, steelwork is still limited for consolidation purposes. Moreover, the wide damage provoked by earthquakes to industrial buildings have induced scientific research to investigate the seismic vulnerability of such constructions much more. In the current study, the attention has been, therefore, focused on the use of steelwork systems as anti-seismic intervention techniques from a precast RC industrial warehouse hit by the 2012 Northern Italy earthquakes. Besides the usefulness of steelwork in implementing reliable techniques against earthquakes, the paper has the aim of discussing the different seismic behaviour of the building deriving from dissimilar beam-to-column joint types obtained using steelwork interventions. Other than the widely diffused static scheme with hinges, other types of joints (semi-rigid and rigid), along with the presence of a rigid roof, have been investigated, and the different seismic risk indicators derived from these static schemes have been achieved, highlighting the case of the best seismic behaviour of the warehouse. Finally, the effectiveness of local steel interventions in improving the efficient global response of the building has also been highlighted. [ABSTRACT FROM AUTHOR]

The paper focuses on the assessment of the seismic performance of Menta Dam, a bituminous faced-rockfill dam located in Southern Italy. The dam was designed in the '70s and a comprehensive assessment of hydraulic and seismic vulnerability has been recently performed according to most recent Italian dam regulations. The present work aims at predicting the displacement capacity of the embankment as an indicator to assess the overall seismic vulnerability of the system. To this aim, different displacement-based methods, which can be classified in the framework of simplified dynamic analyses, have been applied. The results of empirical approaches and of Newmark's type dynamic analyses are compared to the ones obtained by a novel application of Direct Displacement-Based Assessment (DDBA) method for embankment structures. The latter approach seems to be promising, since it is capable to furnish the maximum displacement experienced by the dam crest for progressively increasing seismic actions, and its probability of exceedance; hence, the likelihood of reaching a threshold damaged condition can be deduced and usefully plotted in terms of fragility curves. [ABSTRACT FROM AUTHOR]

Following a seismic event that occurred years ago in Central Italy, the public opinion was growing and growing a concern on the adequacy of educational buildings all across Italy. This activated several political decisions and a consequent technical effort is in progress. Technically speaking one has to manage the classical problem of retrofitting existing buildings. However, the legal environment goes across national codes, targeted guidelines and the professional need of achieving pragmatic solutions based on ethical and social acceptation schemes.This paper introduces the topic in its worldwide exception and focuses then on some operative aspects in the Italian situation. It outlines the consolidated steps along this technical process and emphasizes the weak aspects one meets when going across the designers' reports. [ABSTRACT FROM AUTHOR]

In this paper, empirical fragility curves for reinforced concrete buildings are derived, based on post-earthquake damage data collected in the aftermath of earthquakes occurred in Italy in the period 1976–2012. These data, made available through an online platform called Da.D.O., provide information on building position, building characteristics and damage detected on different structural components. A critical review of this huge amount of data is carried out to guarantee the consistency among all the considered databases. Then, an in-depth analysis of the degree of completeness of the survey campaign is made, aiming at the identification of the Municipalities subjected to a partial survey campaign, which are discarded from fragility analysis. At the end of this stage, only the Irpinia 1980 and L'Aquila 2009 databases are considered for further elaborations, as fully complying with these criteria. The resulting database is then integrated with non-inspected buildings sited in less affected areas (assumed undamaged), to account for the negative evidence of damage. The PGA evaluated from the shakemaps of the Italian National Institute of Geophysics and Volcanology (INGV) and a metric based on six damage levels according to EMS-98 are used for fragility analysis. The damage levels are obtained from observed damage collected during post-earthquake inspections through existing conversion rules, considering damage to vertical structures and infills/partitions. The maximum damage level observed on vertical structures and infills/partitions is then associated to the whole building. Fragility curves for two vulnerability classes, C2 and D, further subdivided into three classes of building height, are obtained from those derived for specific structural typologies (identified based on building height and type of design), using their frequency of occurrence at national level as weights. [ABSTRACT FROM AUTHOR]

The paper compares several simplified methods proposed in the literature for assessing the seismic vulnerability of existing buildings. Type and number of input and output data, limitations of use for different structural typologies, and complexity of use are examined for each methodology to identify the most suitable for assessing the vulnerability of a given class of buildings, based on the available data, the computational effort, and the type of vulnerability judgment. The selected methods were applied to a sample of school buildings located in the province of Naples (Italy). Data were available due to a digital platform and were used to verify the possibility of providing reliable large scale vulnerability judgments based on a reduced set of information, without carrying out additional surveys. The most simplified methods were applied to a sample of about a thousand of buildings, while more detailed methods, needing more information, were applied to a smaller sample. The comparison between the results obtained from different methods allows highlighting advantages and weaknesses of each, so as to identify the convenience in their use according to the specific available information and the objectives of the analysis, finally to evaluate which is more or less safe. [ABSTRACT FROM AUTHOR]

The paper presents a detailed report on a large sample of masonry churches damaged by the 2016–2017 Central Italy seismic sequence. The first part of the work analyses the seismic sequence to give an overview of the occurred events in terms of both ground motion parameters and macro-seismic intensities. The surveyed data are organized into a database made, to date, of 990 cases, which represent almost one-fourth of the whole surveys performed during the emergency phase. Such a significant statistical sample was used to carry out a regional scale typological analysis in order to identify the most recurrent typologies of churches present in Central Italy. The analysis of the observed damage and usability outcomes allowed drawing some conclusions on the behaviour of the inspected churches under the 2016–2017 seismic sequence. The collected data were used to create damage probability matrixes for homogeneous classes of churches at different damage levels and, successively, to implement the corresponding fragility curves in terms of PGA. [ABSTRACT FROM AUTHOR]

The paper presents an interactive kinematic limit analysis approach that can be handled also by inexperienced users for a reliable evaluation of the seismic vulnerability of masonry towers. The procedure requires only a 3D Computer-Aided Design CAD representation of the tower and the mechanical properties to assign to the different volumes. Five possible failure mechanisms are hypothesized, corresponding to those more frequently observed during post-earthquake surveys. They are all constituted by few macro-blocks mutually roto-translating and the code proposed automatically optimizes the shape of the selected failure mechanisms with a Genetic Algorithm GA approach, minimizing the failure multiplier—in agreement with the upper bound theorem of limit analysis—so furnishing quickly an estimation of the collapse acceleration and the crack pattern at collapse. The approach has several advantages, the most important being (1) the possibility to account for the actual geometry of the tower in an extremely detailed manner (so considering openings, irregularities, mass variation along the height, etc.), (2) the drastically reduced computational burden needed (only the recursive evaluation of the principle of virtual powers is required), (3) the adaptation of the failure mechanisms to the specificity of the problem treated, (4) the possibility to apply distributions of horizontal loads different from standard ones and finally (5) the possibility of utilization for all those practitioners not familiar with finite elements and computational limit analysis. The practical procedure proposed is validated against FE pushover computations and non-linear dynamic analyses conducted on two historical towers located in northern Italy, showing perfect agreement with results obtainable by means of complex procedures certainly not manageable at a common professional level. [ABSTRACT FROM AUTHOR]

This paper addresses the large-scale classification of the seismic vulnerability of nonstructural components in school buildings. A rapid visual screening methodology is proposed that highlights the factors that likely have a major effect on the seismic behavior of nonstructural building components. This methodology is based primarily on questionnaire forms that are used to construct a nonstructural index and priority ranking that identifies the most vulnerable category of nonstructural components. Because numerical answers in the questionnaires can produce unreliable results, a calibration of the categories by weight is proposed via fragility functions to obtain a vulnerability index. Finally, the developed methodology is applied to a case study of school buildings in Italy. [ABSTRACT FROM AUTHOR]

Soon after the earthquake that damaged L'Aquila municipality and its Province in the Abruzzi Region, Italy, on the 6th of April 2009, a widespread damage and usability assessment of buildings was launched. In 3 months, about 70,000 buildings were inspected, with the AeDES form, by public servants and professionals coordinated by the Italian Civil Protection Department. The paper, after describing the procedures and the form that were used for the assessment, discusses the time evolution of the inspections and analyses the data on building type and seismic damage. The empirical damage distribution conditional upon seismic intensity and building type is provided and the role of several vulnerability factors, such as the quality of masonry, the construction year, the number of stories, and the pre-existing damage, is highlighted. Lastly the damage consequences, such as the immediate occupancy conditional upon building damage and building type, are reported. [ABSTRACT FROM AUTHOR]

This paper presents the experimental application of a new method for seismic vulnerability assessment of buildings recently introduced in literature, the SMAV (Seismic Model Ambient Vibration) methodology with reference to their operational limit state. The importance of this kind of evaluation arises from the civil protection necessity that some buildings, considered strategic for seismic emergency management, should retain their functionality also after a destructive earthquake. They do not suffer such damage as to compromise the operation within a framework of assessment of the overall capacity of the urban system. To this end, for the characterization of their operational vulnerability, a Structural Operational Index (IOPS) has been considered. In particular, the dynamic environmental vibrations of the two considered strategic buildings, the fire station and the town hall building of a small town in the South of Italy, have been monitored by positioning accelerometers in well-defined points. These measurements were processed through modern Operational Modal Analysis techniques (OMA) in order to identify natural frequencies and modal shapes. Once these parameters have been determined, the structural operational efficiency index of the buildings has been determined evaluating the seismic vulnerability of the strategic structures analyzed. his study aimed to develop a model to accurately predict the acceleration of structural systems during an earthquake [ABSTRACT FROM AUTHOR]

Artworks play a fundamental role in the cultural and economic assets of communities, enhancing their identity and helping with social integration. Despite their importance, they are not always adequately protected against degradation, which can be induced by aging, atmospheric and human-induced occurrences, and catastrophic events. Earthquakes certainly represent one of the main risks for art objects; however, traffic, construction works, and shipment can also represent a threat to art goods. Therefore, the assessment of the vulnerability of art collections to dynamic excitations plays a crucial role in their conservation, and it has been collecting increasing attention from researchers, academics, and museum managers. This work focuses on the vulnerability of the art collections exhibited at the "Gaio Cilnio Mecenate" museum in Arezzo. Namely, it aims to assess the effective dynamic loading experienced by the artworks, which is a function of the dynamic propagation played by the foundation soil, the building, and the displayers used for the exhibition. In this study, the dynamic properties of some of the displayers used for exhibiting the art collections are investigated by performing an experimental survey. The analysis of the experimental data led to the assessment of the proper frequencies of the displayers, which were compared to those of the building and the foundation soil of the museum. [ABSTRACT FROM AUTHOR]

Following major seismic events occurred in Italy over the last 50 years, a notable amount of data relevant to post-earthquake damage of ordinary buildings was collected. These data today represent an inestimable scientific heritage, useful for prevision and prevention purposes, including calibration of vulnerability models for seismic risk assessment and formulation of damage scenarios. However, the data sets resulting from different inspection tools developed over the years are not immediately comparable with each other. The need for enhancing the reliability of prevention models and more effectively support strategic decision-making has moved the Italian Civil Protection Department to undertake, since 2014, a specific project with this ambitious goal. Developed with the technological support of Eucentre Foundation, the web-gis platform, named Da.D.O. (Observed Damage Database), is meant to store and to share data from large post-earthquake damage campaigns occurred in the past. Da.D.O. is addressed to Civil Protection Department users, members of the scientific community and Regions, though its access could be further extended in the future to other stakeholders. The paper describes goals, contents and capabilities of the IT platform, which, at present, includes data sets relevant to nine seismic events (or sequences) occurred from 1976 (Friuli earthquake) to 2012 (Emilia-Romagna earthquake). [ABSTRACT FROM AUTHOR]

Italy is located in a very active seismic zone, and many earthquakes have marked the country, some of them in the recent past. In order to take adequate measures of seismic prevention and protection, in the last decades, the Italian Civil Protection Department (DPC) initiated a survey and introduced a specific form for the quick and/or post-seismic assessment of buildings. This is useful to obtain statistics on the types of structures and their vulnerability and a judgement on the damage, leading to a decision about the possibility of reuse and/or the level of retrofitting to be applied. Those activities have been developed since the beginning of 2000. This task is currently carried out by the Italian DPC-ReLUIS project research, line WP2 on the inventory of building structures, setting up the CARTIS form for any structural type, like masonry, reinforced concrete, precast concrete, steel, and timber structures, the latter being mainly related to large span buildings, extensively used in Italy. In this context, the paper presents the first draft of the CARTIS form for large span timber structures that provides a general description for typical structural schemes, through the singular points commonly considered as seismic structural vulnerabilities. Moreover, the statistics on timber large span structures based on a sample of 10 buildings is presented. [ABSTRACT FROM AUTHOR]

The paper presents some numerical results on a Romanesque masonry church located in Emilia-Romagna (Italy), a region recently stricken by a devastating seismic sequence on 20 th - 29 th May 2012. A full investigation of the damages and their comparison with advanced FE analyses, in both linear and nonlinear range are carried out. FE limit analyses are performed through non-commercial software proposed by one of the authors. A remarkable consistency is found among limit analysis results, real performance of the structure under seismic excitation and advanced nonlinear dynamic analyses. In particular, both damage patterns and active failure mechanisms found numerically are consistent with that observed on the church after the seismic event. The results put in evidence the insufficient strength of the apse for combined shear/bending actions, the columns of the central nave for bending, as well as the façade for overturning of the upper part. A seismic upgrading by means of CFRPs composite materials is proposed, designed and analysed quantitatively using FEs, finding an optimal fit between the required performance and the invasivity reduction. The interaction between CFRP strips and masonry substrate is accounted for assuming the behaviour of the reinforcement in agreement with Italian Guidelines for r.c./masonry strengthening with composite materials (CNR DT200). It is found that, with a targeted design, it is possible to prevent premature collapses of the macro-elements, strongly increasing the load carrying capacity of the structure. [ABSTRACT FROM AUTHOR]

This paper develops a model to forecast unreinforced masonry buildings’ usability, i.e. the condition of a building being habitable or occupiable after a seismic event. The model is based on scores given to seven building parameters that are usually easy to survey: building position within the structural aggregate, number of storeys above ground, construction timespan, structural class, presence of strengthening interventions, roof type, and pre-existing damage to structural elements. Usability coefficients are calibrated for each category of each parameter, by varying macroseismic intensity and regressing data from the 2009 L’Aquila earthquake in central Italy. The parameters contribute to the creation of a synthetic index, according to weights or loading computed through principal component analysis. Usability probability matrices are determined and they can be used for territorial scale scenario assessment, as shown with an application to an entire historical centre. [ABSTRACT FROM AUTHOR]

• Real-time data acquisition and structural health monitoring using wireless sensors. • Use and comparison of different sensors (i.e. MEMS and force-balance units). • Use of dynamic identification methods (i.e. output-only or forced-vibrations ones). • Calibration of models to reproduce the actual dynamic response (adjacent buildings). • Formulations to assess the seismic vulnerability of existing buildings. This paper presents a methodology to perform the seismic vulnerability assessment of existing buildings. It starts with the acquisition of structural data from available construction drawings and field investigations to create a preliminary finite element model. Then, a wireless sensor network is used to collect the structural response at different locations. The sensors are connected and synchronized to each other to download and process data in real time. Modal identification methods, such as output-only and forced vibration techniques, are used to determine the modal characteristics and consequently calibrate the structural model for the subsequent vulnerability assessment. The proposed methodology is applied to a reinforced concrete school building in Italy. The seismic vulnerability is evaluated using a variety of alternative formulations. In particular, material nonlinearities and contact interaction at the structural joints are considered. [ABSTRACT FROM AUTHOR]

The seismic sequences occurred in Italy during the last decades confirmed the vulnerability of historical centres and the need for novel procedures aimed at preserving the cultural heritage and mitigating the structural risk. Building conservation and safeguard require a multidisciplinary approach, so that an accurate assessment of buildings conditions, both conservative and structural in nature, can be accomplished; as a result, potential risk factors and the associated interventions to increase the resilience of sites and historic buildings can be successfully identified. Herein, an insight on the technical literature offers some reflections about a reliable framework for conservation plans that could comply with the current knowledge and technology, and therefore potentially defined proactive. The opportunities given by the integration of information systems and structural monitoring techniques are analysed in the light of a SWOT analysis able to support a rational approach to the preservation of historical centres. The proposed SWOT matrix is the result of an interdisciplinary effort and reflects the key features of a real case, paradigmatic of many historical centres of the Abruzzi Region. In such a perspective, this study represents a step forward an effective and rational approach to the structural maintenance and preservation of historical centres. [ABSTRACT FROM AUTHOR]

The great influence of site effects on damage patterns produced by seismic events of the past, stresses out the need to find proper relationships between the site local conditions and the potential damage that existing buildings may experience under earthquakes of different intensity. This issue proved to be relevant, especially for those masonry buildings in small historic centers, such as the ones belonging to the Apennine areas of Italy that suffered serious damage after the 2009 L'Aquila and the 2016–2017 Central Italy seismic sequences. Some of these centers showed a not regular damage distribution, suggesting that site effects influenced the seismic response of their buildings. In this perspective, this paper provides an attempt to correlate earthquake damage to site effects, focusing the attention on two historic centers of the Abruzzi region, Campotosto and Cortino, which were damaged by the 2016–2017 Central Italy seismic sequences and for which the amplification factors of the subsoil were carefully identified, resulting more influencing were higher damage was observed. First, the damage patterns observed after the 18 January 2017 seismic shock are represented in terms of Damage Probability Matrices and maps developed in GIS environment. Moreover, the data collected in terms of stats are interpreted through the application of the binomial probability distribution, in order to check its reliability in reproducing the gathered frequencies. Finally, in order to justify the damage of some specific buildings, the results of site response analyses are compared with the damage observed punctually on three damaged masonry buildings. • Damage Scenarios observed after the 2016 Central Italy Earthquakes on a Italian minor historic center have been put in relation with the results of a 3rd level Micro zonation study. • The binomial distribution proved to work well when buildings affected by site amplification effects are not included in the scenario; • The different damage levels observed after the earthquake have been justified according to the analysis of the average spectral acceleration measured for their esteemed frequencies and accounting for site amplification effects. [ABSTRACT FROM AUTHOR]

Portal-frame reinforced concrete precast industrial facilities built in Italy between 1960 and 1990 have shown high vulnerability during recent seismic events interesting Emilia region. Post-earthquake damage observations have shown that most of collapses interested portal-frame structures arranged with dry beam-to-column friction joints because of the loss of support due to sliding of beams with respect to columns. At the same time severe damage to column base cross-sections was recognized even in the case of portal-frame systems with beam-column connection devices (fixed joints). The paper investigates the dynamic behaviour of portal-frame precast industrial facilities, especially addressing the inelastic displacement demand as function of the generalized mechanical response of beam-to-column joints. Portal-frames are idealized as 2D inelastic single degree of freedom systems. A framework based on a parametric model developed in OpenSees is defined to build inelastic spectra of maximum relative beam-column displacement demands and maximum column top displacement demands. Inelastic displacement demand spectra are defined for four different sites in Italy (Messina, Mirandola, Naples and Turin), characterized by different seismic hazard. Analytical expressions of spectra approximating numerical results are finally derived to be used for rapid displacement capacity/demand assessments of portal-frame industrial buildings with friction joints or fixed joints. The approach can account vertical component of seismic excitation in a simplified way and can be also used to assess the effectiveness of retrofitting interventions. • A framework to build inelastic displacement demand spectra of RC portal-frame facilities is proposed. • The method can be used for portal frame buildings with friction and fixed joints. • Inelastic displacement demand spectra are defined for four different sites in Italy. • Analytical expressions of spectra are also provided and can be simply used in practice engineering. • The approach can account vertical component of seismic excitation in a simplified way. [ABSTRACT FROM AUTHOR]

The big earthquake of August 24, 2016 and subsequent major shocks severely damaged many historic villages in Central Italy and dramatically showed the intrinsic vulnerability of the diffused architectural heritage. The St. Agostino church is one of the collapsed historical buildings, being inside the epicentre village of Amatrice. During the long seismic earthquake swarm, progressively the church was damaged and monitored. This multidisciplinary study of the damage of the church includes correlations of all the data derived from three steps geomatics surveys (3D aerial and terrestrial models): the archival drawings and images documenting previous events distressing the building, the previous strengthening intervention, and finally the seismic site response analysis (from Amatrice's accelerometric station). Through a back analysis carried out by a finite elements model, it was possible to understand the seismic vulnerability of this historical building, in relation to the previous interventions and damage events. The proposed methodology, based on the interdisciplinary data analysis, provides useful information for the next strengthening projects of damaged historical monument. [ABSTRACT FROM AUTHOR]

Summary In seismic risk assessment of structures, fragility functions are the probabilistic characterization of vulnerability at the component and/or structural level, expressing the probability of failure as a function of a ground motion intensity measure (IM). Fragility curves, in general, are structure‐ and site‐specific, thus a comparison of fragility curves, then of vulnerability, is not straightforward across multiple structures. Also, it could be the case that hazard at a site of interest is not available for the IM originally considered in the fragility assessment. These situations require to convert fragility curves from an original IM to a target one. The present study addresses a hazard‐consistent probabilistic framework for converting spectral acceleration‐based IMs from an original IM to a target IM at a given site. In particular, three conversion cases, under different assumptions on the explanatory power of the involved IMs with respect to structural failure, are discussed: (a) a vector‐valued IM consisting of the original and target IMs, magnitude, and source‐to‐site distance; (b) a vector‐valued IM consisting of the original and target IMs; and (c) the original (scalar) IM only, assuming that structural response, given the IM, is statistically independent of the other ground motion variables. In this framework, the original fragility functions are characterized using the state‐of‐the‐art methods in performance‐based earthquake engineering, then the fragility curves as a function of the target IM are evaluated through applications of the probability calculus rules, ensuring consistency with the seismic hazard at the site of interest. The conversion strategy is illustrated through the applications to three‐, six‐, and nine‐story Italian code‐conforming reinforced concrete buildings designed for a high‐hazard site in Italy. The study shows that, in most of the cases, the converted fragility curves have agreement with the reference curves directly developed in terms of the target IM. Cases in which least agreement was found are likely due to the models used to obtain the terms required by the conversion equations. [ABSTRACT FROM AUTHOR]

Churches struck by the earthquake sequence of 2016–2017 in Central Italy confirmed their seismic vulnerability, significantly higher than the one of other unreinforced masonry structures. This resulted in a much wider area affected by significant damages to churches, which were characterised by a rich variability of materials, typologies, dimensions and styles. In the area where significant damages were observed for ordinary buildings, most of the churches exhibited total or partial collapses. The time sequence of the main shocks helped in preventing casualties in churches although the collapse of a bell-gable in Accumoli caused victims in a neighbour house during the first event of August 24th, 2016. Damage surveys to churches were carried out on more than 4000 buildings, in a land area of about 30 000 km2 from September 2016 to May 2017. The data collected during the post-earthquake surveys represent a valuable source of information for better understanding the vulnerability of these structures as well as the effectiveness of past retrofitting interventions. Some examples are reported to show both damage progression due to the cumulated effect of repeated shaking and state-of-the-art strategies for short-term countermeasures. [ABSTRACT FROM AUTHOR]

This study proposes a methodology based on machine learning (ML) algorithms for rapid and robust classification of building structural types (STs) in multispectral remote sensing imagery aiming to assess buildings' seismic vulnerability. The seismic behavior of buildings is strongly affected by the ST, including material, age, height, and other main structural features. Previous works deployed in situ data integrated with remote sensing information to statistically infer STs through supervised ML methods. We propose a transferable methodology with specific focus on situations with imbalanced in situ data (i.e., the number of available labeled samples for model learning differs largely between different STs). We learn a transferable model by selecting features from an exhaustive set. The transferability relies on deploying geometric features characterizing individual buildings; thus, the model is less sensitive to domain adaption problems frequently induced by e.g., changes in acquisition parameters of remotely sensed imagery. Thereby, we show that few geometry features enable generalization capabilities similar to models learned with a large number of features describing spectral, geometrical or contextual building properties. We rely on an extensive geodatabase containing almost 18,000 building footprints. We follow a Random Forest (RF)-based feature selection strategy to objectively identify most valuable features for prediction. Furthermore, the problem of unbalanced classes is addressed by adopting two approaches: downsampling the majority class and modifying the classifier internally (weighted RF). The implemented model is transferred on the challenging urban morphology of the Val d'Agri area (Italy). Results confirm the statistical robustness of the model and the importance of the geometry features, allowing for reliable identification of STs. [ABSTRACT FROM AUTHOR]

The presence of the largest part ofWorld Heritage sites in a seismically-prone area, like Italy, demands always greater measures to protect the most important built heritage, as well as the minor architecture. This requires a constant improvement of the current protocol from the damage survey and the provisional safety measures to the final intervention. This procedure is summarized, briefly, here and additional practical suggestions are given to improve the activities, based on the experience of on-site volunteers during the damage survey after the earthquake that struck Italy in 2016. Basic issues on the recurrent characteristics of historic masonry buildings, that make them often complex constructions with unexpected behaviour, are fundamental in the preparation of the volunteers in surveying damage. This helps in reducing evaluation mistakes and in designing the provisional safety structures aimed at the preservation of built heritage to the extent possible. Some examples of incorrect interpretation of the damage in historic buildings are reported here. In conclusion, only the awareness that it is necessary that a correct understanding of the recurrent or, on the contrary, peculiar, characteristics of a historic building plays a key role in the damage evaluation and in its subsequent protection from further damage. [ABSTRACT FROM AUTHOR]

Recent major earthquakes in the Italian territory have reaffirmed the seismic vulnerability of precast industrial buildings typical of past Italian building practices, highlighting structural deficiencies observed during previous events and primarily related to the transfer of horizontal forces between structural and nonstructural elements. An intrinsic lack of shear and ductility capacity has been observed in simply supported beam-to-joist and beam-to-column connections, primarily constituted by vertical steel dowels or solely relying on shear friction, with or without neoprene pads. These connections were designed neglecting seismic loads and their premature failure was observed during recent seismic events to cause a loss of support of beam elements, owing to the relative movements of elements, and the collapse of part of the buildings, primarily the roof. The seismic displacement demand of the industrial buildings under consideration is larger than traditional RC frame structures owing to their higher flexibility, according to both higher interstory height and to a cantilevered static scheme. Furthermore, this high flexibility may also result in displacement incompatibility between structural and nonstructural elements, such as precast cladding panels, causing their connection failure. On the basis of detailed field observations on a relevant number of buildings, collected just after the earthquakes, seven representative industrial facilities are examined to outline the primary vulnerabilities of one-story precast concrete structures not designed and detailed for seismic loads. [ABSTRACT FROM AUTHOR]

Vulnerability is a big issue for small inland urban centres, which are exposed to the risk of depopulation. In the climate of the centre-northern part of Italy, and in the context of the recent concentration of a high number of earthquakes in that area, seismic vulnerability can become the determinant cause of the final abandonment of a small town. In some Italian regions, as well as in Emilia Romagna, municipalities are implementing seismic vulnerability reduction policies based on the Emergency Limit Condition, which has become a basic point of reference for ordinary land planning. This study proposes an approach to seismic vulnerability reduction based on valuation planning for implementation within the general planning framework of the Faentina Union, a group of five small towns located in the southwestern part of the Province of Ravenna, Italy. This approach consists of three main stages: knowledge—the typological, constructive, and technological descriptions of the buildings, specifically concerning their degree of vulnerability; interpretation—analysis with the aim of outlining a range of hypotheses with respect to damage in case of a prospective earthquake; and planning—the identification of the courses of action intended to meaningfully reduce the vulnerability of buildings. This stage includes a cost modelling tool aimed at defining the trade-off between the extension and the intensity of the vulnerability reduction works, given the budget. [ABSTRACT FROM AUTHOR]