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The seismic assessment of the vulnerability of existing public structures, especially school buildings, is a crucial issue in seismic prone countries. Recently, several national and regional programs and activities have focussed on the mitigation of Italian public buildings. They promote the scheduling of public buildings' structural safety assessment and, when needed, the design and execution of strengthening interventions. Nevertheless, the three strong earthquakes that occurred in the last decade in Italy, Abruzzo (2009), Emilia (2012), and Central Italy (2016), confirmed the vulnerability of school buildings and the social importance of their quick re-opening after a damaging earthquake. In the present paper, the activities carried out on 1514 school building structures in the aftermath of the 2016 Central Italy earthquake sequence are reported and analysed. According to survey data collected by post-earthquake usability inspections, the paper analyses the school buildings characteristics, damage level and extent to structural and non-structural components as well as the correlation between seismic intensity and observed damage. [ABSTRACT FROM AUTHOR]

This paper focuses on the structural performance of existing masonry and reinforced concrete bridges which were surveyed in the aftermath of the 2016 Central Italy earthquakes. Typical bridge vulnerabilities are first reviewed, as they provide a reference for the response of the bridges that were damaged by the 2016 earthquake swarm. Case studies are then discussed and preliminary numerical analyses are carried out to interpret the observed failure modes. In general, all surveyed masonry bridges experienced some extent of damage, particularly when built with poor-quality materials and subjected to geotechnical-induced effects. However, they offered a robust response in terms of collapse prevention. The majority of existing reinforced concrete bridges, although designed primarily for gravity loads, exhibited acceptable performance; however, local damage due to the poor maintenance of the structural systems was observed, which affected primarily the non-structural components of the bridges. [ABSTRACT FROM AUTHOR]

Non-structural elements represent most of the total construction cost of typical buildings. A significant portion of the total losses in recent earthquakes worldwide, has been attributed to damage to non-structural elements. Damage to non-structural elements occurs at low levels of ground shaking, and can significantly affect the post-earthquake functionality of buildings. However, in Europe, limited prescriptions are provided in the codes for seismic design of non-structural elements and this may partially explain why it is so common for these elements to perform poorly during earthquakes. This paper describes the observed damage to non-structural elements following the 2016 Central Italy earthquake. The most commonly damaged elements were partition walls, ceiling systems, non-structural vaults, chimneys, and storage racks. As a result, it was highlighted the need to introduce seismic regulations devoted to improving the seismic performance of non-structural elements and to reduce the associated economic losses, loss of functionality, and potential threats to life safety. [ABSTRACT FROM AUTHOR]

The earthquake sequence started on May $$20$$ th 2012 in Emilia (Italy) affected a region where masonry constructions represent a large part of the existing building stock and the construction of new modern masonry buildings is a common practice. The paper is focused on the performance of common architectural configurations, typical for residential or business use. The large majority of old masonry buildings is made of fired clay bricks. The seismic performance of these buildings is particularly interesting since major past earthquakes in Italy affected areas with mainly stone masonry structures. Apart from examples showing systematic or peculiar structural deficiencies governing the vulnerability of several buildings, the overall seismic performance of these structures to repeated shaking, with PGA as large as 0.25-0.3 g was rather good, despite the major part of them were only conceived for carrying vertical loads. In fact, seismic design is mandatory in the area only since 2003. Modern low-rise masonry buildings erected after this date and incorporating seismic design and proper detailing resulted in most cases practically undamaged. The examples reported in the paper allow an evaluation of the superior performance of seismically designed modern masonry buildings in comparison to older ones. [ABSTRACT FROM AUTHOR]

For important facilities, such as hospitals or schools, advanced seismic risk assessment methodologies have been developed and are now available for use by owners and facility managers. These include seismic hazard analysis coupled with structural and non-structural response and damage analyses leading to a final consequence analysis that provides indications of performance measures, which are often referred to as decision variables. Typical decision variables are repair costs, probability of collapse of the entire building and downtime. These decision variables do not provide specific information regarding the likelihood of individual rooms to remain functional after an earthquake. For the case of a hospital, for example, information regarding the functionality of specific critical rooms (e.g. operating or emergency rooms) could influence major design/retrofit decisions by the owner or facility manager. The main objective of this paper is to present, through a case study hospital building in Italy, a methodology for assessing the loss of functionality of individual rooms in critical facilities following an earthquake event. The methodology includes all the aspects that are usually considered individually in seismic risk assessment, such as ground motion selection for probabilistic seismic hazard analysis, structural performance of the building, and the performance of non-structural elements that can affect the functionality of selected rooms. [ABSTRACT FROM AUTHOR]

This paper addresses the structural damage to the main buildings of the cities of Reggiolo and Carpi after the primary earthquake shocks on May 20th and 29th, 2012, in Emilia Romagna. The damage survey, performed via form-based methods, highlights the different seismic behaviour of several types of buildings, especially those having historical features, and the consequences of the damage in terms of costs. Moreover, an analysis of some failure mechanisms activated in Reggiolo enables the evaluation of the local peak ground acceleration, due to the soil amplification. [ABSTRACT FROM AUTHOR]

Many countries exposed to high levels of seismic risk, including Italy, are facing a huge challenge in promptly quantifying post-earthquake damages to their built historical heritage. In this context, structural health monitoring plays a fundamental role allowing to continuously track changes in selected damage-sensitive features. However, monitoring data interpretation is often not univocal and may be affected by large uncertainty, provoking false positives and false negatives. Hence, this research proposes a novel approach for post-earthquake structural condition assessment by exploiting the aggregation of different sources of information, notably steering from both monitoring and visual inspection campaigns, in order to take risk-informed decisions. More in depth, an automatic tool is proposed to detect and locate structural damages in monumental structures with the aid of a data fusion approach including vibration-based system identification, static and dynamic measurements, finite element (FE) and surrogate modeling, Bayesian-based model updating and visual inspections. In a preliminary phase, potential damage-sensitive regions in the structure are identified through FE-based numerical analysis and engineering judgment. Then, the solution of the inverse problem aimed at deriving the Bayesian posterior statistics of the uncertain parameters is entrusted to a computational-effective surrogate model (SM). Finally, the Bayesian-based updated parameters are adjusted considering the different allowable sources of information to achieve a final assessment. The effectiveness of the proposed approach is demonstrated by using the recorded data acquired in the Consoli Palace, an historical building located in Umbria, central Italy, which has been continuously monitored since 2017 using dynamic, static and environmental sensors and which has been hit by low-intensity earthquakes in 2021. [ABSTRACT FROM AUTHOR]

Remarkable damage to non-structural elements and sometimes to structural members was surveyed in buildings retrofitted with dissipative bracing (DB) technologies recently hit by moderate-to-medium amplitude earthquakes. Damage is a consequence of the delayed contribution of protective systems to the seismic response of the buildings, caused by too high activation forces of dissipaters. In view of this, a sizing procedure for DB systems incorporating fluid viscous (FV) spring-dampers is implemented in this study. The procedure provides a simplified version of a recently proposed energy-based design criterion, and an extension of it by including a pre-evaluation of the activation force of the FV devices with respect to the normative Serviceability Design Earthquake (SDE)-related seismic demand. The sizing procedure is applied to the retrofit design of a demonstrative case study, represented by a school built in Italy in the early 1980s. Noticeable seismic vulnerabilities of the above-ground steel structure of the building are assessed in current conditions, highlighting local unsafety conditions of the profiles constituting the reticular steel columns starting from the SDE. A retrofit intervention consisting in the installation of a DB system equipped with FV spring-dampers is presented for the steel structure, designed by applying the proposed sizing method. The final verification time-history analyses confirm the activation of the FV devices at the SDE, and the attainment of the targeted elastic structural response up to the Maximum Considered Earthquake normative level. [ABSTRACT FROM AUTHOR]

The non-smooth contact dynamics method was selected to investigate the damage occurred to typical masonry churches (namely Apennine churches) belonging to Central Italy areas affected by the seismic activity started in 2016. The investigated buildings show discontinuous dynamics since the optioned method gave the chance to properly model the temples as multi rigid body systems using the Signorini's impenetrability condition and the dry-friction Coulomb's law, achieving a thoughtful response to ground seismic solicitations. The results provided by the assessment grant an overview of the most common damages and failure mechanisms, giving the guidelines to restoration projects that fully respond to structural needs. [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]

The central Italy seismic sequence began in the latter half of 2016 and continued well into 2017, causing severe damage in the villages close to the source and causing hundreds of casualties. It is a sequence especially interesting to study, from the perspective of seismic actions experienced by structures, because it saw nine M ≥ 5.0 earthquakes within a period of 5 months, rupturing parts of the complex central Apennine mountain range fault system. Consequently, some of the main earthquake engineering issues that arose are the multiple locations where the code-mandated seismic actions were exceeded in more than one of the main events of the sequence and the number of pre- and low-code existing buildings that suffered heavy damage or collapse due to the intensity of individual earthquakes and the cumulative effect of repeated damaging shocks. The present article picks up on these topics and uses probabilistic seismic hazard, as well as the multitude of strong ground motion recordings available from the sequence, to provide a discussion on certain issues, that are all related to the topical subject of seismic actions. These issues are: (1) the unsurprising exceedance of code spectra in the epicentral areas of strong earthquakes; (2) the particular spectral shape and damaging potential of near-source, pulse-like, ground motions, possibly related to rupture directivity; and (3) structural non-linear behaviour in the wake of a sequence that produces repeated strong shaking without the necessary respite for repair and retrofit operations. [ABSTRACT FROM AUTHOR]

In the aftermath of the Mw 6.0 August 24, 2016 Central Italy earthquake, the authors carried out a reconnaissance survey in the municipality of Amatrice and gathered extensive photographic evidence of damage, with emphasis on 37 reinforced concrete buildings located outside the historical centre. Damage distribution is generally represented by widespread cracking and/or collapse of the masonry infill panels at the lower buildings' stories. Moreover, damage was observed in the columns due to the interaction with masonry infill panels. Starting from the collected information, POST—a mechanics-based damage prediction model—was applied in order to compare predicted damage distribution and damage observed during the field reconnaissance. The comparison shows an overall good agreement between the results of the POST method and the observed damage with a slightly conservative tendency by POST. [ABSTRACT FROM AUTHOR]

Data of the Italian National Institute of Statistics are collected aimed at characterizing Reinforced Concrete (RC) building stock of the area struck by the 2012 Emilia earthquake (number of storeys, age of construction, structural typology). Damage observations, collected right after the event in reconnaissance reports, are shown and analyzed emphasizing typical weaknesses of RC buildings in the area. The evolution of seismic classification for Emilia region and RC buildings' main characteristics represent the input data for the assessment of non-structural damage of infilled RC buildings, through a simplified approach (FAST method), based on EMS-98 damage scale. Peak Ground Acceleration (PGA) capacities for the first three damage states of EMS-98 are compared with registered PGA in the epicentral area. Observed damage and damage states evaluated for the PGA of the event, in the epicentral area, are finally compared. The comparison led to a fair agreement between observed and numerical data. [ABSTRACT FROM AUTHOR]

The medieval fortresses are a very common and distinctive type among the Emilian historical constructions and the earthquake of May 20 and 29, 2012 highlighted their high vulnerability. Starting from the analysis of the geometrical and constructive features, the interpretation of their seismic vulnerability has been based on an accurate damage assessment and supported by the numerical results of typical configurations. An abacus of recurring seismic damage mechanisms in fortresses has been proposed: it in particular concerns the towers and their interaction with the fortress perimeter walls. Moreover, the seismic response of the most important fortresses in the epicentral area has been described referring to their historical notes, the recent interventions and their influence on the seismic damage. [ABSTRACT FROM AUTHOR]

The article discusses earthquakes in Emilia region of Italy that occurred on May 20, 2012 and May 29, 2012. Topics include the earthquake magnitude, damage to buildings and aftershocks. Casualties, emergency response by Department of Civil Protection (DCP) of Italy and emergency declaration by the country's National Cabinet. Ground acceleration, vernacular buildings and losses to agriculture has also been mentioned.