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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]

Traditional ancient Tibetan buildings (TATBs) date back hundreds of years. The seismic performance of TATBs constructed with stones and mud was analyzed by utilizing structural subscale features (materials, walls, and structures). The key to load-bearing in TATBs is the three-leaf stone wall. Based on the mechanical properties of materials, compression tests and quasistatic static tests of walls, this paper confirms that the seismic resistance capacity of the three-leaf stone wall of TATBs is unable to meet Chinese standards. The aims of this study are to present the dynamic behavior of TATBs by shaking table tests. According to the experimental data, the transcendence intensity magnification calculation method is modified to calculate the seismic vulnerability of TATBs. The results show that when the peak acceleration of ground motion is 1.042 m/s2, 1.598 m/s2 and 2.881 m/s2, TATBs undergo slight damage, moderate damage, and severe damage, respectively. [ABSTRACT FROM AUTHOR]

A comprehensive understanding of the elements at risk, through the identification of the main hazards, level of exposure and different dimensions of the vulnerability of the communities, is an essential step toward the definition and adoption of more effective risk reduction strategies. Historic urban centres have received special attention in the assessment of damage and physical vulnerability to earthquakes, but it is well known that vulnerability also depends on the social and demographic characteristics of communities. This paper discusses the application of a holistic approach aimed at assessing the seismic vulnerability of historic urban centres by considering their physical and social dimensions. Two index-based methodologies are presented, and the data are analyzed using the CENSUS block as the unit of study, which is scarcely present in the literature. The results of both indices are crossed through a matrix, which allows the classification of the blocks in five levels of priority and are mapped using a Geographic Information System tool. The Historic city centre of La Serena, one of the oldest in Chile, was selected as a case study. This historic city centre still preserves historic buildings of raw earth of diverse architectural typologies widely distributed throughout the country, which makes it relevant, not only by itself but as a model that can be replicated and extrapolated to other historic centres of similar constructive characteristics. [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]

The determination of seismic risk in urban settlements has received increasing attention in the scientific community during the last decades since it allows to identify the most vulnerable portions of urban areas and therefore to plan appropriate strategies for seismic risk reduction. In order to accurately evaluate the seismic risk of urban settlements it should be necessary to estimate in detail the seismic vulnerability of all the existing buildings in the considered area. This task could be very cumbersome due to both the great number of information needed to accurately characterize each building and the huge related computational effort. Several simplified methods for the assessment of the seismic vulnerability of existing buildings have been therefore presented in the literature. In order to estimate the occurrence of damage in buildings due to possible seismic phenomena, the published studies usually refer to response spectra evaluated according to seismic events expected in the territory with assumed probabilities. In the present paper seismic events are instead simulated using a modified Olami–Feder–Christensen (OFC) model, within the framework of self-organized criticality. The proposed methodology takes into account some geological parameters in the evaluation of the seismic intensities perceived by each single building, extending the approach presented in a previous study of some of the authors. Here, a large territory in the Sicilian oriental coast, the metropolitan area of Catania, which includes several urbanized zones with different features, has been considered as a new case study. Applications of the procedure are presented first with reference to seismic sequences of variable intensity, whose occurrence is rather frequent in seismic territories, showing that the damage can be progressively accumulated in the buildings and may lead to their collapse even when the intensities of each single event are moderate. Moreover, statistically significant simulations of single major seismic events, equivalent to a given sequence in terms of produced damages on buildings, are also performed. The latter match well with a novel a-priori risk index, introduced with the aim of characterizing the seismic risk of each single municipality in the considered metropolitan area. The proposed procedure can be applied to any large urbanized territory and, allowing to identify the most vulnerable areas, can represent a useful tool to prioritize the allocation of funds. This could be a novelty for risk policies in many countries in which public subsidies are currently assigned on a case-by-case basis, taking into account only hazard and vulnerability. The use of an a-priori risk index in the allocation process will allow to take into due account the relevant role of exposure. [ABSTRACT FROM AUTHOR]

This paper presents a seismic vulnerability analysis of historic brick masonry buildings in Vienna, Austria from the period of the Austro-Hungarian monarchy (1840–1918). The vulnerability study is based on comprehensive data from the devastating earthquake damage to the masonry buildings in Zagreb, Croatia on March 22, 2020, which are from the Austro-Hungarian monarchy and comparable to Viennese buildings from that period, as well as on comprehensive numerical structural analyses calibrated on in situ test series. The statistical analysis of the earthquake damage to the Zagreb masonry stock and the comprehensive numerical simulations, allowed profound conclusions about the proportional damage distribution over individual structural areas of the masonry buildings, considering construction-specific characteristics such as the building height, the structural regularity/irregularity or the construction type under the ground level. This study enhances the still limited knowledge about the vulnerability of the historic brick masonry buildings from the period of the Austro-Hungarian monarchy and allows extensive conclusions about the seismic vulnerability of these buildings. [ABSTRACT FROM AUTHOR]

Constructing a seismic vulnerability assessment model is crucial for emergency response and mitigating seismic risk. In the wake of increased usage of machine learning, it helps the assessment model to produce more spatial and quantitative results with higher speed, providing a global view of seismic vulnerability in large areas. This paper explores the applicability and performance of different machine learning algorithms in vulnerability assessment. Three regression algorithms of supervised learning (multiple linear regression, BP neural network and support vector machine) are adopted for testing and validation of the models. The detailed vulnerability inventories of different categories of civil structures under Ludian earthquake are compiled according to field investigation and adopted as the training set. Various kinds of damage ratio are determined to consider the different degrees of impact on civil structures under earthquake. Four aspects of factors containing structure category, topographical, seismic, comprehensive factors are selected as independent variables. It is found that the prediction error shows distinctions in different categories of civil structures irrespective of the algorithms, suggesting the necessity of considering structure category in seismic vulnerability assessment using machine learning. Nonetheless, the highest success rates are obtained using BP neural network, with an RMSE of less than 0.05. [ABSTRACT FROM AUTHOR]

The possibility of characterising an existing building based on a limited set of attributes would permit building a semantical, graphical or even conceptual model that could serve as a reference for analytical purposes. Providing that the intent of the analysis and the evaluation procedures are consistent with each other and coherent with the description, it is plausible to assume that the data required to build such a conceptual model could be obtained by resorting, for example, to an ad-hoc survey composed of a set of pre-selected parameters. In the context of a growing interest in preserving Mexican cultural heritage, there has been a continuous effort to catalogue the buildings that, under the corresponding legal definition, are considered historical monuments; in this case, all constructions dated from the early 16th century until 1900. This catalogue has allowed putting together a comprehensive database of the Mexican architectonic heritage. Among other applications, this catalogue has been used to support intervention decision making, particularly in the sequence of recent seismic events in Mexico. Much of the information included in the current version of the catalogue is related to the buildings' structural characteristics, making it pertinent to discuss the suitability of using these data for feeding simplified vulnerability assessment methodologies. With this in view, the present paper explores and discusses the feasibility of a transversal use of an index-based seismic vulnerability assessment approach for façade walls together with the Mexican National Catalogue of Historical Monuments. For such, the methodology—a pre-established vulnerability assessment approach for façade walls—was applied to a set of representative masonry buildings damaged by the 2017 Puebla earthquake. Furthermore, this paper offers a proposal for enhancing the existing survey to obtain data that would permit to include a semi-quantitative index for vulnerability as a part of the current catalogue works. [ABSTRACT FROM AUTHOR]

In the last few decades, Jammu and Kashmir has faced many moderate to large earthquake events that caused catastrophic damage to the physical infrastructure and significant socioeconomic loss. The growing number of infrastructure projects, as well as previous historical records of severe earthquakes in this area demand the study of the seismic vulnerability of tunnel. In this paper, an attempt has been made to develop the seismic fragility curves for circular tunnels located in four distinct zones classified based on seismic microzonation results of the Jammu Region (JR). The damage probabilities of shallow tunnels in these zones decrease fiercely as lining thickness increases. Furthermore, increasing PGA by 0.2 g increases the exceedance probabilities for minor, moderate, and extensive damage exposed to 82%, 89%, and 93%, respectively for shallow tunnels. The fragility functions proposed for Jammu and Kashmir were employed to assess seismic risk for tunnels under Udhampur Srinagar Baramulla Rail Link (USBRL) project. Most of the tunnels in Phase 3 showed more than 50% of damage probability for the region specific defined seismic environment. [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]

Typological-observational methods still constitute one of the most commonly applied tools for evaluation of the seismic risk and vulnerability of the existing building stock. Their efficiency is mainly related to the effectiveness of the procedure for deriving fragility curves, and the reliability and completeness of the database that describes the building stock. This paper presents a comparison between the vulnerability and damage distribution assessment provided by fragility curves used in the Macroseismic and Heuristic methods, and a comparison of exposure evaluation methodologies according to two different approaches, namely a compartment- and a building-scale survey. An application to the case study of the residential building stock in the historic center of Alcamo, a town of 45,000 inhabitants in Western Sicily (Italy), shows the major reduction in fragility provided by recalibration of the masonry buildings' ductility values that characterize the Heuristic method. Moreover, the efficiency of the compartment scale survey approach, based on the CARTIS typological-structural characterization method of ordinary buildings in urban areas, is underlined. [ABSTRACT FROM AUTHOR]

This paper explores and validates the use of ground shaking scenarios generated via 3D physics-based numerical simulations (PBS) for seismic fragility studies. The 2009 L'Aquila seismic event is selected as case-study application, given the availability of a comprehensive post-earthquake database, gathering observed seismic damages detected on several building typologies representative of the Italian built environment, and of a validated numerical model for the PBS of ground shaking scenarios. Empirical fragility curves are derived as a function of different seismic intensity measures, by taking advantage of an improved statistical technique, overcoming possible uncertainties in the resulting estimates entailed by data aggregation. PBS-based fragility functions are compared to the corresponding sets of curves relying on updated ShakeMaps. The predictive capability of the adopted simulation strategies is then verified in terms of seismic damage scenarios, by respectively coupling PBS- and ShakeMap-based fragility models with the corresponding ground shaking scenarios. Comparison of observed and predicted damage distributions highlights the suitability of PBS for region-specific seismic vulnerability and risk applications. [ABSTRACT FROM AUTHOR]

In these studies, we show that the seismic risk of large cities in developing countries is most often due to the high vulnerability of apartment buildings. To reduce the seismic risk in the territory of such cities, it is important to study the dynamics of its change over time, since the risk is not formed immediately and for various reasons. Establishing these causes is important for both risk prevention and reduction. As an object of study, we chose the capital of Armenia, the city of Yerevan, whose high seismic risk was formed mainly due to the construction of a large number of seismically vulnerable apartment buildings and the associated rapid mechanical population growth. The seismic risk of the territory of Yerevan has been repeatedly estimated, while the dynamics of risk growth over time has not been studied. This paper is aimed at studying the dynamics of the growth of seismic risk in the territory of Yerevan for 1900–2019, depending on the seismic hazard level, the number of vulnerable apartment buildings, and the number of residents in these buildings. To estimate the risk, a special methodology based on the lessons of the devastating Spitak earthquake 1988 was used. It was confirmed that a high level of seismic risk was formed mainly from 1957 to 1989 due to an underestimation of the seismic hazard, the construction of a large number of apartment buildings with high and medium seismic vulnerability, rapid growth, and an uneven population distribution. [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]

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]

This paper analyses the seismic vulnerability of various rammed earth medieval fortifications situated in Southeastern Spain, where seismic events with intensity over VII have taken place in the last millennium, using the vulnerability index method. This method begins with the choice of a certain initial value, V0, of the vulnerability index, which is obtained from a preset range between maximum, V 0 max , and minimum, V 0 min , values, which are likely for vulnerability indices, according to the constructive material characteristics and based on expert judgments. Rammed earth structures have not yet been studied using the vulnerability index method, despite the fact that they are quite common medieval structures in Spain and other countries in the Mediterranean region, many of which are also heritage sites, and hence are legally protected. Intervention priorities on them have been determined from the results in this paper with the aim of reducing their seismic vulnerability. For the different rammed earth techniques, a proposed primary value Vp = 0.76 together with some other material modifiers (construction typology and quality, current material porosity and density, and superficial deterioration) make the range of values V0 vary between 0.58 and 1.02. Moreover, structural behavior modifiers (MK) have been adapted to the various defensive rammed earth structural typologies used for these fortifications allowing us to obtain individualized vulnerability index values. Three rammed earth fortifications damaged by historical earthquakes and located in SE Spain have been used to validate the method, in which values of V0med range between 35.2 and 89.1% and upwards and the vulnerability index IVmed may vary between 27.9 and 70.7% and upwards as compared to those used by other authors for castles. Besides, the proposed method has been used by carefully choosing six rammed earth fortifications (two towers, two walls and two castles) in SE Spain which are representative of different construction systems, structural typologies and topographies. Furthermore, the mean damage grade and the probability of its occurrence is determined for each fortification based on PGA data and site effects, taking into account a probabilistic seismic scenario for a 975 year return period, in accordance with existing legislation. In the end, direct relations are established between the seismic vulnerability and the types of material and the typology of the fortifications. We have carried out a sensibility analysis in order to learn about the influence of the constructive technique, the material condition and the structural typology on the damage grade value. The results show that lime-crusted rammed earth technique and tower typologies are the most vulnerable structures while topography is somehow less important. The results suggest that for half of the structures analyzed for the given scenario the probabilities are above 80% for damage grade 4 and 5 (EMS-98). [ABSTRACT FROM AUTHOR]

Assessing the actual seismic economic losses of regional building portfolios is essential to quantify the seismic resilience of urban and rural areas. Various building clusters indicate different damage levels under real earthquakes of different intensities, which directly leads to apparent anomalies in the actual economic losses of various building portfolios. This paper proposes an economic loss assessment model for large-scale regional building portfolios, considering the damage probability matrices. The traditional empirical vulnerability quantification method is optimized and updated by combining the analysis methods of probability risk, reliability, macroseismic intensity, and instrument intensity. Five typical building sample sets (total survey area: 56,937.1893 × 104 m2) of 57 typical cataclysmic earthquakes that occurred in Yunnan Province, China, from 1993 to 2022 are collected and processed, and an updated fragility dataset is established. The calculation model considering empirical structural vulnerability and economic loss quantitative parameters is innovatively developed. Combined with the quantitative approaches of the multidimensional nonlinear fitting model and the established regional empirical structural vulnerability database, the seismic loss evaluation model of large-scale regional structures is established. Ultimately, the earthquake loss point cloud and matrix of typical building portfolios in the large-scale zone are developed using cloud analysis and the proposed seismic loss evaluation model. [ABSTRACT FROM AUTHOR]

A growing attention has been paid to the deep renovation of RC buildings, particularly focusing on their structural vulnerability and on the development of retrofit strategies; however, the issue of the in-plane diaphragm action and the capacity of existing floors has rarely been addressed. Although floor capacity does not seem critical for the seismic capacity of existing structures, commonly affected by greater vulnerabilities, it may become critical when an additional lateral force resisting system is introduced. This paper investigates the in-plane capacity of beam and hollow-clay-block floor system, typical of the European post-WWII RC buildings. Considering the diaphragm action as associated with an in-plane tied-arch mechanism developing within the floor thickness, the main failure mechanisms are discussed, and some simplified equations are provided to preliminary estimate the maximum capacity of floors. Experimental and numerical analyses are than carried out to validate the simplified analytical model. The relevant influence of possible staircase openings on the in-plane load paths and on diaphragm flexibility and capacity are also considered. Finally, the influence of the floor capacity on the seismic vulnerability assessment and in the conceptual design of a seismic retrofit intervention is discussed. This preliminary study shows that only some of the beam-and-block floor systems have a reliable in-plane capacity, while other typologies cannot serve as floor diaphragms. When the diaphragm action can be relied upon, the diaphragms often exhibit a fairly stiff behaviour up to a brittle failure, which is commonly associated with the ultimate capacity at the tied-arch supports. [ABSTRACT FROM AUTHOR]

The paper presents a new simplified mathematical model for predicting the structural seismic response of buildings. The model, denominated Seismic Model from Ambient Vibrations (SMAV), is based on the experimental modal parameters identified from ambient vibration and only a few information about the geometry and the structural typology of the building. After a short review of the Multi Rigid Polygons model, recently illustrated and validated in an other paper by some of the authors, that allows to estimate the seismic participation factors of the experimental modes also for buildings characterized by complex shaped plan and structural irregularity along the height, the attention is focused on a new stochastic approach for modeling the seismic response of masonry buildings. In particular this new approach aims to take into account the non linearity occurred during a seismic event so that the nonlinear behaviour of the building is considered by reducing its modal frequencies according to the response amplitude. The reduction of the natural frequencies, extracted by Operational Modal Analysis from ambient vibrations, is computed according to specific probabilistic curves: the Frequency Shift Curves (FSCs). This curves provide the percentage reduction of the natural frequencies as a function of the maximum roof drift reached during the strong motion and they are obtained, for some specific masonry typologies, through a Monte Carlo analysis carried out using a simple mechanical model of a masonry panel with geometric and mechanical parameters that vary according to their probabilistic distributions. The seismic response of the building is then computed through a linear equivalent analysis in which an iterative algorithm updates the resonant frequencies according to the specific FSC curve. The concept of structural serviceability index (IOPS), expressing the probability of the building to remain operational, is also introduced. Finally, a comparison between the seismic response computed by the model and the experimental seismic response of the Pizzoli town hall, a masonry existing building endowed with a permanent accelerometer monitoring system, is illustrated. [ABSTRACT FROM AUTHOR]

Recovering and preserving ancient churches is necessary to ensure the transmission of this cultural heritage to the future generations. To this scope, it is necessary to evaluate their performance in seismic prone areas, to design interventions capable of reducing their vulnerability ensuring also their safety use for the faithful. In this paper, investigations on seismic performance of masonry churches are illustrated by applying two different numerical methods on a case study, an existing brick masonry church. The seismic assessment is conducted by applying two simplified methods proposed by the current Italian Directive containing the Guidelines for assessment and reduction of cultural heritage seismic risk. Moreover, linear kinematic analysis is used also for investigating the influence of main parameters governing to the main façade simple overturning and narthex longitudinal response. The investigations performed highlight that the activation multiplier of macro-element response mechanism may significantly vary according to the assumptions made and that also, as narthex longitudinal response, a minimization procedure of the activation multiplier is required. [ABSTRACT FROM AUTHOR]

The purpose of this investigation is to compute the seismic vulnerability in the Rif area in order to estimate the occurrence susceptibility to liquefaction sites. In addition to that, evaluating the liquefaction potential is one of the most useful investigations for risk mitigation and seismic hazard zonation and assessment. The parameter of the seismic vulnerability can be quantified and expressed by Kg index which is derived from the well-known ambient noise horizontal-to-vertical spectral ratio (HVSR) method of Nakamura. In this paper, the depicted analysis involves 15 broadband stations extended across the Rif region. The HVSR method was conducted on the whole micro-tremor data of 2014. By extracting the fundamental frequency F0 and the amplification factor A0 from the micro-tremor data, the Kg index was calculated, and the liquefaction potential was evaluated. The lowest estimated Kg value was about 0.19 (34.97° N–3.32° W), while the highest value reached 11.93 (35.33° N–4.96° W) which refers to the station situated near the Bou-Ahmed river branch north Morocco. Accordingly, the low Kg values exhibit a dominance in the Rif area, which can be related to minor water content, thus unsaturated ground granules. [ABSTRACT FROM AUTHOR]

This paper reports the results of several on-site investigations carried out by the authors in the last 20 years in central Italy (Umbria, Marche, Emilia and Abruzzo regions) on masonry wall panels. The use of stone and brickwork masonry has been common for centuries not only for rural residences but also for public and religious buildings. In many areas, where the stone was abundant, stone became the material of choice for all constructions. However from rubble stone to perfectly squared stones, the mechanical properties may highly differ. Test results are reported with an accurate survey and analysis of the masonry typology and mechanical characterization was performed according to ASTM standards and consisted of measurements of shear properties. The paper also reports the experimental results of full-scale tests conducted on brickwork walls using different bonding patterns, mortar types and brick dimensions. These data were recorded in terms of shear strength, elastic properties and deformation capacity and are of critical importance for design, reinforcement or retrofit purposes in earthquake-prone areas. All tests were conducted on site from pre-existing undamaged wall panels. Finally, test results are compared with existing standards and indicate that masonry shear strength is sometimes overestimated by the Italian Building Code. [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 seismic vulnerability assessment of old masonry buildings is essential not only to buildings with recognised historical and heritage value but also to ordinary residential masonry buildings. Thus, and resorting a wide set of damage data collected after the 1998 Azores earthquake, this paper addresses the topic of the seismic vulnerability assessment of traditional masonry buildings through the calibration and application of a simplified vulnerability assessment method to the old city centre of Horta (Faial Island), in Portugal. In this case study, 192 buildings were assessed using this methodology, and vulnerability and loss scenarios were analysed using an integrated Geographical Information System tool. As is discussed in this paper, such procedure could allow city councils or regional authorities to plan interventions based on a global view of the site under analysis, leading to more accurate and comprehensive risk mitigation strategies, which can than support the requirements of safety and emergency planning. [ABSTRACT FROM AUTHOR]

Equivalent-frame modelling for the estimate of in-plane seismic vulnerability of masonry wall is endorsed by international codes. However, in presence of irregular layouts of openings, the definition of equivalent-frame becomes non-unique and may lead to epistemic modelling errors. The aim of this paper is to develop a simplified tool to estimate such errors as functions of the level or geometric irregularity. Four types of irregularity are considered and quantified by geometric indexes. Nonlinear static analyses are carried out through an equivalent-frame model and a nonlinear finite-element model. It is assumed that both models are exact for perfectly-regular walls, while in presence of irregularities only the continuum approach is able to correctly predict the vulnerability, so that the difference between the two results can be taken as a measure of the error of the equivalent frame. A regular wall is taken as case study and both numerical models are calibrated on experimental data. The four typologies of irregularity are introduced separately, each in steps of increasing magnitude. The results show that the equivalent frame approach is usually not safety-preserving and may be affected by a significant error. A tentative global measure of irregularity, weighting the average effects of each irregularity type, is proposed. The resulting simplified relationship between irregularity level and expected error can be used to define a confidence factor on the modelling, which penalizes the application of the equivalent frame in case of irregular walls. Eventually, an applicability limit of the equivalent-frame model might be set. [ABSTRACT FROM AUTHOR]

The 2015 Gorkha earthquake in Nepal damaged more than 28,000 school buildings across the affected areas. Nepali school buildings can broadly be categorized into special moment-resisting frame, brick masonry, stone masonry, timber, and composite construction (steel and masonry). This paper proposes a new methodology to designate seismic vulnerability of these building categories. The proposed methodology is based on the field study of around 3389 school buildings in central Nepal. Structural, non-structural, architectural, site conditions, seismic enhancement and retrofitting, and multi-hazard parameters are incorporated to develop a scoring system. Indexed based system is introduced using sensitivity analysis which allows the designation of total vulnerability scores to individual buildings. The scores are modified based on the level of seismic strengthening/retrofitting. Based on the total vulnerability score, a qualitative vulnerability level is assigned to the individual building. The results highlight that more than 90% of Nepali school buildings are moderate to very highly vulnerable. [ABSTRACT FROM AUTHOR]

The island of Hispaniola, shared by the Dominican Republic and Haiti, is located in a subduction zone between the North America plate and the Caribbean plate. In addition, there are 13 geological faults in the interior of the island, some of which have shown the potential to generate earthquakes of magnitude 7.5 and higher. Thus, the whole island is considered to be a high seismic risk region. In the past 100 years, several earthquakes have affected both parts of the island. In the case of the Dominican Republic, two earthquakes stand out: a magnitude 8.1 earthquake on August 4, 1946, north of the Samaná Province, which caused a tsunami, soil liquefaction, and the loss of about 100 lives, and a magnitude 6.5 earthquake on September 22, 2003, in the city of Puerto Plata, which caused significant damage for infrastructures. Among the observed effects, the partial and total collapse of several school buildings had a remarkable impact on local communities. In addition to the high seismic risk, a large part of the national infrastructure may exhibit high vulnerability to earthquakes because the seismic regulations had been the same for 32 years, namely from 1979 to 2011. During these three decades, thousands of structures were built nationwide, including essential facilities such as hospitals and schools. Considering that the current student population in public schools in the Dominican Republic is over 2 million, with the majority attending buildings that were designed with the 1979 seismic code and which proved to be highly vulnerable during the Puerto Plata earthquake, it is vital to take measures that reduce the risk and minimize potential earthquake damage to school buildings. In this context, the Technological Institute of Santo Domingo (INTEC) has undertaken recently a project with the main objective to assess the seismic vulnerability of 22 schools located in the San Cristóbal Province, in the south of the Dominican Republic. The latter schools were all built prior to the adoption of the current updated seismic code. This paper presents the results of the assessment of the Fernando Cabral Ortega School. Although only the results of a single RC building are presented, the response of such structure can be considered representative of a portfolio of existing schools in Dominican Republic. [ABSTRACT FROM AUTHOR]

This article presents an approach to rapidly predict the seismic vulnerability existing of low-to mid-rise residential reinforced concrete (RC) buildings. In this procedure, Capacity Index is computed considering the cross-sectional orientation and size and material properties of the components of the structural system. This index is modified considering the several coefficients of possible negative impacts of structural irregularities, which are frequently found in RC buildings. Accuracy of the proposed approach has been tested considering 196 RC buildings subjected to earthquakes. The procedure categorizes the buildings either as safe or as unsafe according to whether they meet the life-safety target performance requirement. The analytical results indicate that the consistency of the proposed approach in this paper is about over 90%. Therefore, the proposed approach can be used to asses the seismic performance and vulnerability levels of existing RC buildings. [ABSTRACT FROM AUTHOR]

The present paper deals with the analytical investigation of representative planar masonry-infilled reinforced concrete (MIRC) frames for seismic fragility, performance and demand. The study includes the effect of various patterns of layout for infills panels along the height of reinforced concrete frames. The analytical investigation has been done using non-linear dynamic time-history analysis under collection of forty SAC near-field ground motions using rational hysteretic models for structural components; the results are presented in terms of parameters such as peak inter-storey drift, residual drift and damage index. The outcomes of study are used to develop seismic fragility curves in probabilistic terms for the generic medium-rise MIRC frames. The developed fragility curves can be useful tools in predicting the life and economic losses in the future seismic event. In the current study, efforts are also made to develop curves demonstrating seismic performance and seismic demand for representative MIRC frames. [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 results of an experimental dynamic analysis and structural modelling of the Indiano Cable-Stayed Bridge in Florence, Italy, are presented in this paper. Ambient and traffic-induced vibration tests were first carried out. These allowed extracting the dynamic characteristics of the structure in terms of resonance frequencies, modal shapes and damping. The experimental results were used to set up a finite element model. The geometrical characteristics and the mechanical properties of the materials used in the structural design of the bridge were assumed. The model was then used to evaluate the effects of the static and seismic loads according to the present Italian Technical Code. The results pointed out the good performance of the bridge, even though it had been designed without accounting for the seismic actions. [ABSTRACT FROM AUTHOR]

Iran is located in a very high seismic zone. The current national code of design of buildings referred to as Standard No. 2800 (STD-2800) employs the design-basis earthquake (DBE) based on the uniform hazard philosophy. New generations of seismic codes and related researches have used a uniform risk philosophy instead, where the parameters are defined in order to provide a tool for designing the buildings with equal or at least harmonized collapse probability across the country. In this paper, a risk-targeted seismic design map has been developed for Iran. A seismic hazard model developed by EMME14 project was used for this purpose. A generic collapse fragility function was used, the parameters of which were selected based on sensitivity analyses. Taking into account the seismic hazard model from the EMME14 project, the risk of collapse of the buildings in Iran was calculated once for DBE values provided by STD-2800 and again with the DBE values resulted from the EMME14 model. An acceptable risk level of 1% in 50 years was considered then, to estimate the map of distribution of risk coefficients as well as the map of collapse risk for the buildings in the country. The results show a large dispersion in the risk of collapse across the country, in both cases. Finally, the risk-targeted seismic design map for the country is presented. [ABSTRACT FROM AUTHOR]

The paper deals with the investigation of the seismic behaviour of a masonry church sited in Poggio Picenze (district of L'Aquila) and damaged by the L'Aquila seismic event occurred in Italy on 2009 April 6th. This earthquake, classified as an exceptional event, caused significant damages to about 15,000 buildings. Above all, many of the cultural sites of L'Aquila and the surrounding villages, including churches, palaces and other monuments dating from the Middle Ages and Renaissance, were harmed in a severe way or demolished. The current work is framed in the post-seismic scenario of Poggio Picenze, a small town located about 10 km to the South-East of L'Aquila, and it is aimed at the seismic response assessment of the St. Giuliano church by means of experimental dynamic testing and numerical analyses. Firstly, an experimental campaign based on Ambient Vibration Tests (AVTs), that are non-destructive tests especially applied to historical and monumental buildings for evaluating their modal response, has been performed on the selected construction in the framework of the COST C26 Action as a cooperation activity between the Ss. Cyril and Methodius University of Skopje and the University of Naples "Federico II". As a result, the method has allowed to obtain the dynamic properties of the examined structure, namely natural frequencies, vibration mode shapes and damping coefficients. The experimental results have been subsequently used to implement a numerical FEM model of the church in the ABAQUS non linear code environment. Linear FEM analysis has been carried out to calibrate the experimental results and a suitable investigation in the nonlinear field has been conducted to predict the post-seismic structural behaviour of the church. Finally, the performed analyses have been of a fundamental importance for both detecting damages into the construction and programming effective retrofitting interventions. [ABSTRACT FROM AUTHOR]

The paper deals with the seismic vulnerability of masonry vaults: a review of the results of an experimental campaign recently performed by the authors and a numerical study are presented. In particular, the effectiveness of a strengthening technique based on the application, at the vault extrados or intrados, of a 30 mm thick mortar coating with glass fiber-reinforced polymer meshes embedded is discussed, referring to vaults carrying their self-weight and subjected to a lateral transversal load. The role of the connection of the vault with its abutments is particularly emphasised in this review of the experimental results, evidencing how slides and/or uplifts at the spring sections can reduce the strengthening effectiveness. The numerical study, based on non-linear static analysis, allowed to investigate in depth into the effects of an inadequate skewback configuration: it was found that a ductile connection, which allows plastic rotation at the spring section while maintaining the bending resistance and avoiding shear slip and uplift, is the optimal solution. Moreover, the results of a sensitivity study are also presented, as this permits to evaluate the incidence of the different mechanical and geometrical parameters on the behavior of the vaults and provides useful indications towards a proper design and optimization of the strengthening intervention. [ABSTRACT FROM AUTHOR]

The Indo-Gangetic Plains which lies between the Himalayan mountain ranges and peninsular India is considered to be the region of great concern due to its thick sediments and proximity to the seismically most active zone of India, the Himalayan collision zone. No earthquake loss estimation studies have been taken up previously in central Indo-Gangetic Plains (CIGP) so far. The goal of this paper is to compute the social and economic loss in CIGP region which will raise the awareness of the general public, policymakers and structural engineers about seismic risk in CIGP so that necessary mitigation measures will be taken up in advance. Further, the relative contribution of six input parameters to the overall uncertainty is ascertained from sensitivity analysis. Earthquake loss estimation reveals that Allahabad district, even though demarcated as zone II in IS 1893:2002, has expected economic losses around 9-13 billion dollars and the highest number of homeless and uninhabitable dwellings. Also, model building class (MBC) MMB (mud mortar bricks with temporary roof), comprising of 16.48% of total households in CIGP region, has high collapse rate when compared to other MBCs, due to the fact that those buildings have temporary roof made of wood, bamboo, polythene, plastic, thatch, mud and others. Further, for a scenario magnitude range of Mw 7.5-8.5, the expected human casualties vary between 0.14 and 1.7 lakhs, and the economic losses vary from 18 to 140 billion dollars, respectively. These results may not be unrealistic, as the region happens to be in the seismic bypass of 1905 Kangra and 1934 Bihar-Nepal earthquakes, with an anticipated catastrophic earthquake of Mw > 8.0. The poor quality and low seismic resilience of buildings in CIGP region are the principal reasons for the corresponding huge casualties and economic losses. Finally, from the sensitivity analysis, we found that the most sensitive parameter is magnitude followed by GMPE and source location, respectively. [ABSTRACT FROM AUTHOR]

This paper outlines the seismic vulnerability of rural stone masonry buildings affected by the 2015 Gorkha earthquake sequence. Summary of field observation is presented first and empirical fragility curves are developed from the detailed damage assessment data from 603 villages in central, eastern and western Nepal. Fragility curves are developed on the basis of 665,515 building damage cases collected during the post-earthquake detailed damage assessment campaign conducted by Government of Nepal. Two sets of fragility functions are derived using peak ground acceleration and spectral acceleration at 0.3 s as the intensity measures. The sum of the results highlights that stone masonry buildings in Nepal are highly vulnerable even in the case of low to moderate ground shaking. The results further indicate that in the case of strong to major earthquakes, most of the stone masonry buildings in Nepal would sustain severe damage or collapse. [ABSTRACT FROM AUTHOR]

Despite the importance of spatial planning and urban planning in areas with seismic risk, urban modifiers affecting the vulnerability of buildings have not received special attention from researchers. Some international initiatives such as Benedetti and Petrini (Ind Constr 18:66-78, 1984), the EMS-98 and the Risk-UE project (2003), aware of the importance of this issue have contemplated behavior modifiers, thus ultimately increasing or decreasing the building's vulnerability. This paper analyses urban planning in earthquake zones in order to classify urban modifiers that make cities vulnerable. To this end, the research is based on developments carried out as part of Risk-UE, in its Level I empirical methodology, and aimed at studying behavior modifiers. In order to determine the relationship between urban modifiers and damage, the researchers undertook an exploratory study of such modifiers in the city of Lorca with the aim of establishing their correlation with the damage caused by the 2011 earthquake 3 km from the city. This analysis could be useful for autonomous regions, municipalities and urban planners in establishing Urban Zoning Regulations, constructing new buildings and upgrading the seismic behavior of existing cities. [ABSTRACT FROM AUTHOR]

Tehran, capital of Iran, is located on a number of known and unknown faults which make this mega city exposed to huge earthquakes. Determining locations and intensity of seismic vulnerability of a city is considered as a complicated disaster management problem. As this problem generally depends on various criteria, one of the most important challenges concerned is the existence of uncertainty regarding inconsistency in combining those effective criteria. The emergence of uncertainty in seismic vulnerability map results to some biases in risk management which has multilateral effects in dealing with the consequences of the earthquake. To overcome this problem, this paper proposes a new approach for Tehran's seismic vulnerability classification based on granular computing. One of the most significant properties of this method is inference of accurate rules having zero entropy from predefined classification undertaken based on training datasets by the expert. Furthermore, not-redundant covering rules will be extracted for consistent classification where one object maybe classified with two or more nonredundant rules. In this paper, Tehran statistical zones (3,173 according to 1996 census) are considered as the study area. Since this city has not experienced a disastrous earthquake since 1830, this work's results is the relative accurate with respect to the results of previous studies. [ABSTRACT FROM AUTHOR]

This paper presents a major extension of seismic vulnerability research project on the site of Trakošćan Castle based on the initial horizontal-to-vertical-spectral-ratio (HVSR) results from Stanko et al. (2016). The estimated HVSR site frequencies and HV amplification at Trakošćan Castle can only be used as an indication of the initial soil site frequency and amplification, so-called natural soil model, corresponding to the subsoil profile without the influence of an earthquake. The equivalent-linear (EQL) site response analysis has been carried out for different earthquake scenarios for a maximum input rock peak ground acceleration (PGA) that corresponds to return periods of 95 (0.08 g), 475 (0.18 g) and 1000 years (0.31 g). The aim of the research is to evaluate structural seismic design responses and to determine type and degree of damage caused by local site effect, which is the result of an alluvial basin and topographic influences. The main objective of this research is the formation of local microseismic zones based on an EQL analysis: surface spectral acceleration and amplification maps at the predominant frequency. Based on the HVSR frequency response of the core structure of Trakošćan Castle and the Tower itself (fundamental and higher frequency modes), maps of surface spectral acceleration and soil amplification at different frequencies (3, 5 and 10 Hz) are developed for different input PGA levels (0.08, 0.18 and 0.31 g) to evaluate seismic response of the Castle. Observed amplifications are correlated with ground motion polarization and directionality of the ground motion from the alluvial basin to the hilltop. Shortening of predominant frequencies (lengthening of the period), particularly in the alluvial basin, has been observed with higher input PGA in the EQL analysis. This effect is not manifested in the Trakošćan hill, and predominant frequencies match HVSR frequencies. The use of certain geophysical survey methods at historical sites is a big problem, because terrain features (e.g. steep hills, mountains, ridges, slopes, cliffs) create lack of space and make it impossible to carry out geophysical investigation. Microtremor measurements at historical sites can overcome this limitation and provide local seismic response and vulnerability behaviour of historical monuments without destroying their authenticity. Also, computational modelling can greatly improve the results. The EQL site response analysis on the site of Trakošćan Castle has confirmed and improved the results of seismic response and vulnerability based on HVSR method. [ABSTRACT FROM AUTHOR]

Many reinforced concrete buildings have been built with masonry infill walls for architectural needs without considering their mechanical contribution. However, ignoring the structural influence of infills may lead to significant inaccuracies in the prediction of the actual seismic capabilities of the structure. Aiming at providing numerical tools suitable for engineering practice, simplified methodologies for predicting the nonlinear seismic behaviour of infilled frame structures (IFS) have been proposed, mostly considering the contribution of the infill as an equivalent diagonal strut element. In this paper, an alternative plane macro-element approach for the seismic assessment of IFS is proposed, validated and applied to a benchmark prototype building. The model validation is focused on recent experimental and numerical results that investigate the influence of non-structural infills, also in the presence of different openings layouts. As a benchmark investigation, a multi-storey plane frame prototype, for which the results of pseudo-dynamic tests are available, is investigated and compared to the results obtained by using a commonly adopted single-strut model. The merits and drawbacks of the considered numerical approaches are highlighted. [ABSTRACT FROM AUTHOR]

This paper proposes a modification of the empirical method for seismic vulnerability assessment of reinforced concrete buildings in urban areas. In the RISK-UE LM1 framework, the values of the behaviour modifiers related to: (i) the level of seismic code design; (ii) the number of storeys above ground; and (iii) the structural joint between adjoining buildings, have been modified according to an analysis of the actual seismic performance of buildings and a review of the currently available models, providing continuity to the progress of the previous works published to date. The new model has been applied to the city of Lorca, Spain following the damage data from the earthquake of May 11, 2011. Less dispersion between actual observed and estimated damage in buildings is presented in comparison with the previous studies, with a statistical significance level of 5%, thus achieving a more accurate evaluation of seismic risk based on the typological, structural and urban parameters of the buildings. Nevertheless, future work to further improve these modifiers is necessary in order to achieve a better adjustment between the estimated and observed damage. By using GIS techniques, the proposal can also be used to develop the planning and management of post-earthquake emergency situations, allowing for a better definition of several damage scenarios. [ABSTRACT FROM AUTHOR]

This paper deals with the dynamic response of a free-standing ancient column in the Roman Agora of Thessaloniki, Greece as a means to shed more light on the complex behaviour of rocking bodies under seismic excitation. Numerical analyses utilizing discrete element method were carried out with the use of multiple seismic records selected based on the disaggregation of the seismic hazard for the region of interest. To identify their impact on structural performance, earthquake Intensity Measures, such as Peak Ground Acceleration and Peak Ground Velocity are examined for the case of a column that sustained no visible permanent deformations during the Ms = 6.5 Thessaloniki earthquake of 1978. The analysis revealed a weak correlation of PGA and PGV with the response results and a significant influence of the mean frequency (f) of the seismic motion. No coupling was found between the maximum displacement of the top during the oscillation and the permanent post-seismic deformations. The complementarity of both earthquake Intensity Measures in the structural vulnerability assessment is also depicted. [ABSTRACT FROM AUTHOR]

Within the 2019–2021 research agreement between the Civil Protection Department (DPC) and the Network of University Laboratories for Earthquake Engineering (ReLUIS), the work package WP4 "Seismic Risk Maps—MARS" is specifically devoted to update the 2018 release of the Italian National Seismic Risk Assessment. To this end, the previously considered models of hazard, exposure and vulnerability will be critically reviewed and updated by taking advantage also from the results deriving from other WPs of the DPC-ReLUIS research project. In the present paper some of the most relevant aspects that are being introduced in the development of the new Italian risk maps have been described and shortly analysed. First, a significant upgrade of the vulnerability model implemented in the new version of the platform used for risk calculation (IRMA) is proposed, where reference to the six EMS-98 classes is made also considering regional vulnerability features. Further, empirical data from observed real damage are integrated with results from numerical simulations (mechanical approach), in particular for reinforced concrete buildings. Finally, some special construction types such as schools, churches and bridges are included in order to provide a more comprehensive view of the national risk. [ABSTRACT FROM AUTHOR]

From the beginning of the twentieth century, and due to the rapid increase of reinforced concrete (RC) usage, mixed masonry-RC buildings have emerged. In Lisbon, Portugal, old mixed masonry-RC buildings appeared between 1920 and 1960, representing the transition period between masonry and proper RC. These buildings are often integrated in blocks, and frequently share the side-walls, implying, thus, the need to assess the seismic vulnerability of building aggregates. The present paper approaches the seismic vulnerability assessment of a specific type of old mixed masonry-RC buildings in Lisbon. The study comprises the analysis of a building, both as an isolated structure and inserted in its aggregate, using two approaches: (1) linear dynamic analysis with SAP2000 and (2) nonlinear static analysis by means of 3Muri/Tremuri software. A comparison of both approaches derives a good matching between the obtained results. However, a nonlinear analysis is required to identify, in an adequate manner, the critical areas of the structure requiring strengthening. [ABSTRACT FROM AUTHOR]

The current seismic risk assessment is based on two discrete approaches, actual and probable, validating afterwards the produced results. In the first part of this research, the seismic risk is evaluated from the available data regarding the mean statistical repair/strengthening or replacement cost for the total number of damaged structures (180,427 buildings) after the 7/9/1999 Parnitha (Athens) earthquake. The actual evaluated seismic risk is afterwards compared to the estimated probable structural losses, which is presented in the second part of the paper, based on a damage scenario in the referring earthquake. The applied damage scenario is based on recently developed damage probability matrices (DPMs) from Athens (Greece) damage database. The seismic risk estimation refers to 750,085 buildings situated in the extended urban region of Athens. The building exposure is categorized in five typical structural types and represents 18.80 % of the entire building stock in Greece. The last information is provided by the National Statistics Service of Greece (NSSG) according to the 2000-2001 census. The seismic input is characterized by the ratio, a/ a, where a is the regional peak ground acceleration (PGA) which is evaluated from the earlier estimated research macroseismic intensities, and a is the PGA according to the hazard map of the 2003 Greek Seismic Code. Finally, the collected investigated financial data derived from different National Services responsible for the post-earthquake crisis management concerning the repair/strengthening or replacement costs or other categories of costs for the rehabilitation of earthquake victims (construction and function of settlements for earthquake homeless, rent supports, demolitions, shorings) are used to determine the final total seismic risk factor. [ABSTRACT FROM AUTHOR]

The paper investigates the in-plane performance of horizontal precast reinforced concrete cladding panels, typically adopted in one-storey precast industrial and commercial buildings. Starting from in-field observations of cladding panels failures in recent earthquakes, the seismic performance of typical connections is evaluated by means of experimental tests on full-scale panels under quasi-static cyclic loading. The failure mechanisms highlight the vulnerability of such connections to relative displacements and, therefore, the need to accurately evaluate the connections displacement demand and capacity. An analytical model is developed to describe the force-displacement relationship of the considered connections and compared to the experimental results. In order to determine the seismic vulnerability of such connections and provide design recommendations, linear and nonlinear analyses are conducted taking as reference a precast concrete structure resembling an industrial precast building. The results of the analyses show the importance of a correct estimation of the column's lateral stiffness in the design process and how an improper erection procedure leads to a premature failure of such connections. [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]