A Multidisciplinary Study on the Seismic Vulnerability of St. Agostino Church in Amatrice following the 2016 Seismic Sequence

ABSTRACT

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.     

A Bayesian approach to rapid seismic vulnerability assessment at urban scale

The seismic vulnerability of city centers is commonly assessed by extending the study methods applied to single buildings to urban aggregations. This approach is not always applicable at territorial scale, as it is uneconomical in terms of time and costs. An innovative method provides reasonable large-scale a priori estimation of parameters not directly evaluable from the exterior of buildings by elaborating values which can be measured from the outside. Those parameters are treated as continuous variables, by assigning them a suitable probability density function. The Bayesian approach is adopted, which allows the update of initial hypotheses by using new data gathered during on-site surveys. In this regard, a rapid survey form for the on-site data collection is proposed. An example of its application to a façade of a building structural unit in Santo Stefano di Sessanio in L’Aquila province (Italy) is proposed, showing promising preliminary results for buildings belonging to Italian historical centers.     

The Use of a Large-Scale Seismic Vulnerability Assessment Approach for Masonry Façade Walls as an Effective Tool for Evaluating,Managing and Mitigating Seismic Risk in Historical Centers

ABSTRACT

The vulnerability assessment of the building stock in a given territorial area, such as a city or an entire country, is a key prerequisite for evaluating risk, not only because of the potential physical consequences resulting from the occurrence of an event, but also because it is one of the few aspects in which engineering research can intervene. In fact, the rigorous vulnerability assessment of existing buildings followed by the implementation of appropriate retrofitting solutions can help to substantially reduce the levels of physical damage and economic impact of future events. Particularly regarding the seismic vulnerability assessment of historical centers, the amount of knowledge that has been accumulated over the past decades, together with the broad damage data obtained from post-earthquake damage surveys, provides a singular opportunity to develop and calibrate innovative large-scale seismic vulnerability assessment approaches, which can be used to outline and support risk mitigation and management strategies. This article addresses this issue by discussing the use of a large-scale seismic vulnerability assessment methodology for masonry façade walls as a tool for evaluating the potential benefit resulting from the application of different seismic retrofitting strategies, both considering their contribution to reduce post-event urban losses and accessibility.     

Seismic Assessment of a Monumental Building through Nonlinear Analyses of a 3D Solid Model

ABSTRACT

The paper analyzes the static behavior and the seismic vulnerability of the “San Francesco ad Alto” building in Ancona (Italy), which is currently used as a Regional Headquarter of the Marche Region by the Italian Army and was formerly a monastery. The global static structural behavior and the dynamic properties have been evaluated using the Finite Element modeling technique, in which the nonlinear behavior of masonry has been taken into account by proper constitutive laws. The concepts of homogenized material and smeared cracking are used to evaluate the capacity of the monastery to withstand lateral loads together with the expected demands resulting from seismic actions (N2 method), using a nonlinear static analysis (pushover). The comparison of seismic demand and capacity confirms the susceptibility of these types of buildings to extensive damage and collapse, as frequently observed in similar buildings. This paper aims to point out that advanced numerical analyses can offer significant information on the understanding of the actual structural behavior of historical buildings. It is believed that the methodology and the overall conclusions of this case study are valid for many historical monasteries in Europe.     

Comparing expeditious procedures for the seismic vulnerability assessment on the European territorial context: reliability,feasibility, cost,and time consumption

ABSTRACT

The definition of strategies for the preservation and protection of cultural heritage is a topical issue, especially in view of the increasing relevance of the theme of seismic risk mitigation and reduction.

The prediction of the impact an earthquake could have on existing buildings requires the knowledge of their dynamic behaviour. The procedure to be adopted for this purpose is quite complex and onerous in terms of costs, time, and implementation, especially when the study concerns territorial areas rather than single buildings. The definition of methodologies aimed at respecting the principles of economic sustainability and preserving human life and architectural heritage is of paramount importance to assess seismic vulnerability using available resources. Rapid methods for the seismic vulnerability assessment, aimed at defining buildings vulnerability and intervention priority lists, must be implemented to guarantee the preservation of historical centers.

This article describes the application to some case studies of different methods aimed at creating fragility curves for the vulnerability assessment on the European territorial context. The comparison between a deterministic approach and a new probabilistic one is performed for all case studies, to define the most suitable methodology in terms of reliability and savings in cost and time.     

Assessing Seismic Social Vulnerability in Urban Centers — the Case-Study of Nablus,Palestine

ABSTRACT

Seismic risk depends on three factors: seismic hazard, exposure of assets and communities, and vulnerability—physical and social. Whereas hazard and exposure are harder to act upon, vulnerability can be significantly reduced, if properly characterized for each asset, population, or society in general. This article assesses the social vulnerability and resilience level of the city of Nablus, an important urban center in Palestine. The region, considerably exposed to seismic hazard, features, from the in-built view point, very recent or very old historical buildings, without seismic design provisions. On the socio-economic side, the well-known political conflicts and societal challenges are key vulnerability factors. The method employed was based on Social Vulnerability Indicators (SoVI) extracted from census data, integrated with the more recent SCORECARD approach, which was applied to the urban community of Nablus. The goal was both to obtain an overall vulnerability score for the city and to characterize internal differences among its main areas, connected to its historical urban expansion and patterns. The results show that both physical and social vulnerability can be related and that the city development patterns can mirror the relative social vulnerability.     

Seismic Vulnerability of Historical Masonry Aggregate Buildings in Oriental Sicily

ABSTRACT

The seismic vulnerability assessment of historical UnReinforced Masonry (URM) buildings is a very complex task since it is strongly related to a great variety both of geometrical layouts and of masonry mechanical characteristics. In this article, some results of a Catania University research project, denomined “FIR 2014”, focused on the seismic vulnerability estimation of historical buildings, built in Catania after the 1963 earthquake, are presented. First, a detailed typological analysis of the considered urban fabric, characterized by typical residential masonry buildings, has been performed. Such analysis allowed recognizing an elementary structural modulus, which has been studied according to different geometrical layouts representative of isolated or aggregate buildings. The results of nonlinear static analyses, performed by applying an innovative macro-element approach, allowed for the assessment the seismic vulnerability of typical URM buildings coherently to the Italian seismic code. The adopted macro-element strategy for the seismic assessment of aggregate masonry buildings, although related to a specific historical center, may be applied to similar urban fabrics and can also be used for the calibration and validation of fast seismic assessment strategies, particularly useful for the evaluation of the seismic risk at urban scale.     

Seismic vulnerability assessment methodology for slender masonry structures

ABSTRACT

Slender masonry structures such as towers, minarets, chimneys, and Pagoda temples can be characterized by their distinguished architectural characteristics, age of construction, and original function, but their comparable geometric and structural ratios yield to the definition of an autonomous structural type. These structures constitute a part of the architectural and cultural heritage. Their protection against earthquakes is of great importance. This concern arises from the strong damage or complete loss suffered by these structures during past earthquakes. Seismic vulnerability assessment is an issue of most importance at present time and is a concept widely used in works related to the protection of buildings. However, there is few research works carried out on developing the seismic vulnerability assessment tools for such structures.

This article presents a new method for assessing the seismic vulnerability of slender masonry structures based on vulnerability index evaluation method. The calculated vulnerability index can then be used to estimate structural damage after a specified intensity of a seismic event. Here, 12 parameters are defined to evaluate the vulnerability index for slender masonry structures. Implementation of this methodology is carried out in different types of slender masonry structures to develop vulnerability curves for these structure types.     

Building survey forms for heterogeneous urban areas in seismically hazardous zones. Application to the historical center of Valparaíso,Chile

ABSTRACT

Building survey is an essential data-collection procedure to feed large-scale seismic vulnerability assessment. The available strategies usually consider survey forms to gather information about the urban buildings. The application of the available survey forms poses important challenges for the case of the heterogeneous urban centers including different structural typologies. This work proposes four specific survey forms for traditional structural typologies constructed with masonry, reinforced concrete, mixed steel-reinforced concrete, and timber. The proposed forms request essential information on the parameters necessary for seismic vulnerability assessment, by evaluating the lateral-load resistant system, regularity, condition of conservation, and existing damages. The survey forms were applied to the study of 111 buildings of the historical center of Valparaíso, Chile. The proposed methodology was complemented with the use of Geographic Information Systems to obtain a complete database with the structural characterization of the most representative typologies for future works of large-scale seismic vulnerability assessment.     

Methods to Create a Longitudinal Integrated Demographic and Geographic Database on the Micro-Level

Abstract

The authors develop a methodology to create databases that can be used to add micro-level geographic context to longitudinal historical demographic analyses. The method transforms geographic objects as snapshots (digitized from historical maps) into temporal representations of longitudinal object lifelines and links individuals to these geographic objects. The methodology is evaluated via a case study using historical data from the Scanian Economic Demographic Database. The authors link approximately 53,000 individuals in five parishes for the period 1813–1914 to the property units in which they had lived. The results of this study are a unique contribution in terms of linking individuals to micro-level longitudinal geographic data over such long periods. Thus, these data may provide new knowledge for historical demographic research.     

Developing a Synthetic Index of Land Vulnerability to Drought and Desertification

This paper develops an index of the vulnerability of land to drought and desertification (LVI) for Italy. The index takes into account changes in climate, land use, vegetation cover, soil properties, and population during the period 1990–2000. The LVI was built up through a multivariate approach aimed at assessing the importance of the various indicators included in the synthetic index. Increasing land vulnerability was observed during this time, especially in dry areas of the southern regions. This is interpreted as a consequence of land management practices, agricultural intensification, population pressure, and bio-physical degradation. The LVI can be used in an integrated, decision-support system to evaluate the impact of mitigation policies in rural environments.     

Transboundary river governance and climate vulnerability: Community perspectives in Nepal’s Koshi river basin

Frequent floods in the Koshi River have left the Nepalese vulnerable to erosion and recurring inundation—especially those living on the floodplains. The situation is worsening because water flow in the river is highly uncertain, affected by rainfall in the mountains and by climate change, and influenced by the Koshi barrage, which is governed by the Koshi River Agreement, a bilateral river agreement with India. This study addresses how Koshi River governance contributes to the vulnerability of riverine communities in Nepal by drawing upon ideas about vulnerability and vulnerability mapping. A household survey and interviews were conducted in 2015 for a comparative study of people living on two river islands located upstream and downstream of the barrage. Findings remain relevant because of persistent governance challenges and growing climate change effects, escalating islanders’ vulnerability to recurrent floods. The islanders’ vulnerability was produced locally and also shaped by historical, social, economic, political, geographical, and ecological processes occurring at multiple scales. That insight highlights the need to study the broader political economy of hazard production to understand vulnerability in the context of governance.     

Assessment of risks on a territorial scale for archaeological sites in İzmir

This article focuses on natural, institutional, and human factors threatening archaeological sites. A methodology is developed for assessing risks to multiple assets on a territorial scale. The methodology consists of hazard assessment, vulnerability assessment, and risk assessment. Hazard assessment involves identifying hazard exposure areas and measuring the frequency and intensity of each hazard. Vulnerability assessment incorporates examining physical, managerial, and contextual vulnerabilities of structures and remains. Geographical information systems are utilised for producing hazard, vulnerability, and risk maps. An overall picture of risks for an entire territory allows decision-makers to make informed decisions at an upstream level to limit further degradation and ensure the preservation of archaeological assets. The methodology was tested by conducting a comprehensive study in ?zmir (Turkey), where 229 archaeological sites located in 21 metropolitan districts were studied. The proposed approach provides the promise of applicability across a range of historic environments.     

SIMULATION OF THE FOURIER PHASE SPECTRUM FOR THE GENERATION OF SYNTHETIC ACCELEROGRAMS

This study presents the application of a new method for generating synthetic accelerograms based on statistical distributions for Fourier phase differences and Fourier amplitudes as functions of earthquake magnitude, hypocentral distance and site geology. Two important characteristics of the methodology are that it requires a small number of input parameters and that ground motion time histories can be simulated without any specific modulation function. Two areas with different tectonic patterns (North-Eastern and Central Italy) were selected for the application. The results of our analysis are reliable in the case of Central Italy because the data set is large and quite uniformly distributed, while for North-Eastern Italy our results should not be used for distances greater than 30 km.     

Shear Vulnerability of Historical Reinforced-Concrete Structures

Modern buildings have been characterized by the rapid spread of reinforced concrete as a novel and versatile building material. Within the assessment of existing buildings, the most sensitive structures are those designed in the first half of the 20th century, when the theory of reinforced concrete and the detailing rules were not yet well established. This study considers the issues related to the gradual understanding of the vulnerability at a territorial scale of structural typologies designed only for vertical loads. In particular, the shear behavior of the buildings in the period between 1920 and 1960 is investigated. The shear strength control of the structural elements of an open-air stadium in Southern Italy is carried on according to Eurocode 2, the American Concrete Institute Code, ACI 318R–2008, and a method based on Arslan’s equation. The results are compared with those included in the original calculus report according to the 1930 Royal Decree-Law (RDL 18/7/1930).     

A Microtremor Survey in the Area Shocked by the ML 5.2 Salò Earthquake (North Italy): An Empirical Approach to Determine the Effects of Ground Motions

In this work, the results of a quick microtremor survey performed in the municipalities situated in the epicentre area of the Ml 5.2 2004 Salò earthquake (North Italy) are presented. The aim of this study is to understand if the large amount of damage caused by the event (about 215 million euros only in the areas near to the epicenter) is correlated more to the local surface geology conditions or to the vulnerability of ancient Italian historical centers.

A preliminary seismic zonation was carried out in 5 villages including about 30 measurements of microtremors analyzed by the Nakamura technique (hereinafter HVNR). The points of measurement were carefully selected considering sites located both near damaged buildings and over different local geology conditions (alluvium deposits, fluvial-glacial deposits, debris fans and rock). In order to strengthen the HVNR results and to evaluate the reliability of the Nakamura analysis, a comparison with spectral ratios calculated on earthquakes (hereinafter HVSR) recorded at the strong motion station of Vobarno was made. In general, the outcomes of the survey highlight a possible correlation between local geology conditions and ground motion amplification for different frequency bands. In order to check if this evidence is linked with the damage, a series of macroseismic intensity values were collected for different zones of the investigated area, and a nonparametric correlation approach was used to establish a possible correlation between damage and ground motion amplification for selected frequency bands. The results show, from a statistical point of view, that in the area surrounding the epicenter of the November 24, 2004 mainshock, the damage pattern is not strongly dependent upon the local surface geology but more correlated to the low quality of the civil structures present in the area, including old buildings of the last century.     

Interdisciplinary approach for reconstructing an alder-based historical agricultural practice of the Eastern Ligurian Apennines (NW Italy)

Data from four soil profiles studied through pollen and macroscopic charcoal analyses were used to identify specific palynological assemblages associated with a traditional land-use system documented in the Eastern Ligurian Apennines (NW Italy) between the 18th and early 20th century, concerning a cyclical use of grey alder plots for temporary cultivations involving to the use of controlled fire. This is the first attempt to verify on palynological evidence some hypotheses raised by previous historical ecology studies about the consequences of this agricultural practice (recently named alnocoltura) on past and present vegetation. Our investigations underline (1) high percentages of anthropogenic pollen indicators, (2) increase of Ericaceae percentages, (3) low pollen percentages of Alnus, (4) high macrocharcoal concentrations and (5) high values of palynological richness during periods affected by the alnocoltura cycle according to the historical sources. Similar patterns are also detectable in pollen diagrams from two adjacent peat bogs. The paper shows the strength of an interdisciplinary methodology (field observations, cartographical and archival historical data, palynological and archaeological investigations) for studies of past land-use systems. By demonstrating the necessity of a long-term prospective in environmental reconstructions for the preservation of the cultural landscape, one of the important elements of this research is its potential contribution to issues of habitat management and nature-conservation policy. Further analyses are needed to test the replicability and reliability of the hypotheses derived from this study.     

A Multidisciplinary Approach for the Archaeometric Study of Pozzolanic Aggregate in Roman Mortars: The Case of Villa dei Quintili (Rome,Italy)

This contribution focuses on the study of historical mortars from a Roman archaeological site known as Villa dei Quintili, a monumental villa located in the south‐eastern part of Rome (Italy). The study was carried out on 38 mortar samples, collected from several edifices within the complex. A multi‐analytical approach, including polarized optical microscopy, scanning electron microscopy coupled with energy‐dispersive system and laser ablation inductively coupled plasma mass spectrometry, was used to analyse the pozzolanic material used for the preparation of mortars. Data obtained on both major and trace elements were compared with the compositions of Pozzolana Rossa, Pozzolana Nera and Pozzolanella samples from the Alban Hills volcanic district, collected from a historic quarry nearby, as well as with literature data. The results of such a multidisciplinary approach allowed us to recognize the use of all three pozzolan types for the aggregate fraction of examined mortars from the Villa dei Quintili.     

Seismic Risk Assessment of New Zealand Unreinforced Masonry Churches using Statistical Procedures

ABSTRACT

The 2010–2011 Canterbury earthquake sequence provided extensive evidence of the significant seismic vulnerability of New Zealand unreinforced masonry (URM) churches. Given the high seismicity of the country, the exposure of human lives and the societal significance of ecclesiastic buildings, for both historical and religious reasons, the reduction in seismic vulnerability of this building type is of primary importance. By analyzing the seismic performance of a sample of 80 affected buildings, regression models correlating mean damage levels against ground-motion parameters were developed for observed collapse mechanisms, accounting for vulnerability modifiers whose influence was estimated via statistical procedures. Considering the homogeneity of New Zealand URM churches, the vulnerability models developed for the Canterbury region were extended to the whole country inventory, and a synthetic index was proposed to summarise damage related to several mechanisms. Territorial scale assessment of the seismic vulnerability of churches can assist emergency management efforts and facilitate the identification of priorities for more in-depth analysis of individual buildings. After proper calibration, the proposed approach can be applied to other countries with similar building heritage.