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The 2014 Orkney earthquake caused significant damage to unreinforced masonry buildings in the surrounding townships. After the earthquake, field surveys were conducted to assess the extent of damage in the affected areas. This study reviews data collected from the 2014 Orkney earthquake to investigate damage patterns, evaluate building safety for occupancy, and support fragility curve construction. Damage was quantified based on the European Macroseismic Scale (EMS-98) to assess building safety and conduct regression analysis. The results indicate that the collected data is suitable for investigating damage patterns and determining building safety for occupancy. However, it is not suitable for constructing fragility curves. Empirical fragility curves are typically developed using logistic regression, but this study found the data unsuitable for regression analysis due to sampling errors and limited data quantity. This study recommends the use of first-order approximation methods to supplement the dataset, reducing sampling errors and increasing data quantity. [ABSTRACT FROM AUTHOR]

This paper presents a combined approach for the seismic vulnerability assessment of pitched portal frames by coupling elastic and limit analysis. Pitched portal frames are widely adopted both in civil and industrial building structures, as well as in architectural heritage structures, including cathedral portal frames in ecclesiastical buildings. The seismic vulnerability assessment of such structures is crucial for mitigating territorial seismic risk. In this study, elastic and limit analyses are adopted and combined to evaluate the seismic capacity of pitched portal frames. To this end, a simplified model is proposed to analyze both linear and non-linear responses of these structures under horizontal actions. Although the analysis focuses on two-dimensional (2D) portal frames, it can be extended to three-dimensional (3D) buildings in a straightforward manner due to the specific characteristics of the analyzed structural scheme. The proposed approach provides a preliminary yet efficient evaluation of the seismic vulnerability of buildings with pitched portal frames. Furthermore, the effectiveness of the proposed procedure ensures valuable applicability in large-scale seismic assessments. [ABSTRACT FROM AUTHOR]

In this paper, the seismic vulnerability of churches is assessed using different methods characterized by different levels of complexity depending on the accuracy of the results to be achieved. Specifically, we compare the two main types of methodologies applied in the literature, namely, empirical and analytical methods. Empirical methods assess seismic vulnerability based on engineering judgements. In this study, these evaluations were carried out through an automatic tool, the MACHRO form, which was introduced in the past by the authors with the purpose of making evaluations as objective as possible. Analytical methods evaluate the vulnerability of a stock of churches through linear and nonlinear kinematic analyses performed for the most vulnerable macro-elements, which are treated by means of mechanical models. When the number of churches in the stock is huge, this type of evaluation might prove unfeasible. For this reason, churches are grouped into a manageable number of archetypes in order to be analyzed. The above-described methodologies were applied to a relevant number of churches, aiming to appraise discrepancies in terms of results and highlight advantages and drawbacks of their application. [ABSTRACT FROM AUTHOR]

Fragility curves are fundamental tools in seismic risk assessments, providing insights into the vulnerability of structures to earthquake-induced damages. These curves, which plot the probability of a structure reaching or exceeding various damage states against earthquake intensity, are critical for developing effective modification strategies. This review aims to present the characteristics between building- and site-specific fragility curves, which incorporate detailed local characteristics, and generic fragility curves that apply broader, more generalized parameters. We utilize the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology to systematically review the literature to address key research questions about the methodological differences, applications, and implications of these curve types in assessing seismic risks. The methods involved a comprehensive search and combination of existing studies on the topic, focusing on how these curves are developed and applied in real-world scenarios. The results from this review show that building- and site-specific curves, while more precise, require extensive data and are therefore more complex and costly to develop. In contrast, generic curves, though less accurate, offer a cost-effective solution for preliminary risk assessments over large areas. The conclusions drawn from this review suggest that while each type has its merits, the choice between building- and site-specific and generic fragility curves should be guided by the specific requirements of the seismic risk assessment task, including available resources and the need for precision in the vulnerability estimations. [ABSTRACT FROM AUTHOR]

Fragility curves are fundamental tools in seismic risk assessments, providing insights into the vulnerability of structures to earthquake-induced damages. These curves, which plot the probability of a structure reaching or exceeding various damage states against earthquake intensity, are critical for developing effective modification strategies. This review aims to present the characteristics between building- and site-specific fragility curves, which incorporate detailed local characteristics, and generic fragility curves that apply broader, more generalized parameters. We utilize the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology to systematically review the literature to address key research questions about the methodological differences, applications, and implications of these curve types in assessing seismic risks. The methods involved a comprehensive search and combination of existing studies on the topic, focusing on how these curves are developed and applied in real-world scenarios. The results from this review show that building- and site-specific curves, while more precise, require extensive data and are therefore more complex and costly to develop. In contrast, generic curves, though less accurate, offer a cost-effective solution for preliminary risk assessments over large areas. The conclusions drawn from this review suggest that while each type has its merits, the choice between building- and site-specific and generic fragility curves should be guided by the specific requirements of the seismic risk assessment task, including available resources and the need for precision in the vulnerability estimations.

After an earthquake, legislation tends to permit the rapid demolition of damaged buildings, including the built heritage, for safety reasons, as was the case for many small historic centers after the 2016 earthquake in central Italy. A balance should, of course, be struck between safety and preservation. There must be a willingness to engage in continuous interaction with the various bodies involved in post-earthquake management, particularly in the preventive phase of the complex activities regarding the issues of the seismic vulnerability of historic built. The widespread historical built heritage in Italy requires fast and reliable assessment procedures that allow a large-scale evaluation of the vulnerability of historical buildings before a seismic event. To this end, a proposal is presented here for the inverse use of the protocol for the seismic vulnerability survey of historic centers by means of a system called CARTIS form, coordinated since 2015 by the Italian consortium of Seismic and Structural Engineering Laboratories (ReLUIS). This rapid assessment is compared with an equally fast method for constructing fragility curves, based only on the information available in the ReLUIS–CARTIS database, defining the relationship between the probability of reaching a level of loss of structural safety or a vulnerability index as a function of the seismic acceleration PGA and the ground orography. The methodology outlined could be considered to be progress in cultural heritage diagnostics on a large scale, considering cultural heritage to be the diffuse historical residential masonry buildings that form the historic centers.

The metropolitan area of Lisbon is the region of Portugal with the highest seismic risk, given the coexistence of moderate-to-high hazard with high population density and building stock exposure. The present work addresses the seismic risk assessment of pre-code masonry buildings in this region, accounting various typological classes and conservation states in order to evaluate the consequences in terms of economic losses. The analyses are conducted through a seismic probabilistic approach, considering the site-specific ground motion through a non-stationary stochastic method. The results can serve as a useful guide for decision-making in developing regional seismic risk mitigation strategies. [ABSTRACT FROM AUTHOR]

Cliff-attached structures are structures attached to slopes and connected tightly, which is particularly complex to analyze due to the foundations' unequal grounding and the lateral stiffness' irregularity. In rare earthquakes, seismic waves are usually obliquely incident on the foundation at a certain angle. Therefore, it is not appropriate to consider only seismic waves' vertical incidence, and it is necessary to consider multi-angle oblique incidence. In this paper, based on the theory of viscous-spring artificial boundary and the principle of equivalent nodes at the interface of oblique incidence of ground shaking P-waves, and combined with the dynamic properties related to Buckling-Restrained Brace, the numerical models of slopes and two kinds of cliff-attached structures considering the slope amplification effect and soil-structure interaction are established. The dynamic response of the obliquely incident seismic waves under the action of the cliff-attached vibration reduction structure is studied in depth, and the additional effective damping ratios of the nonlinear energy-dissipated units based on the deformation energy are compared and analyzed. It is shown that under the four oblique incidence angles of incidence (compression waves in the vertical plane) studied in this paper, the seismic dynamic response and damage degree peaked at an angle of incidence of 60°, with a tendency to increase and then decrease with increasing angles of incidence. The ability of an energy-dissipating vibration reduction device to change structural vibration characteristics decreases with an increase in incidence angle. The difference between the total strain energy of the structure in the X-direction (Transverse slope direction) and Y-direction (Down-slope direction) and the total energy dissipation of the dissipative components is obvious, with the X-direction being about 10 times that of the Y-direction. [ABSTRACT FROM AUTHOR]

Substations function as neural hubs within power systems and play pivotal roles in the aggregation, transformation, and distribution of electrical energy. Previous experiences indicate that substation systems are highly susceptible to damage under earthquakes, resulting in a subsequent decrease in power supply functionality. To mitigate the risk of earthquake‐induced damage, a novel approach based on Bayesian theory is proposed to assess the seismic vulnerability of complex engineering systems. The proposed method initially obtains the prior distribution of seismic fragility parameters for electrical equipment through numerical simulations of coupled finite element models. Subsequently, seismic damage survey data and Bayesian updating rules are applied to update the prior probability, obtaining a hybrid fragility function for electrical equipment. The Bayesian network was constructed using logical relations among internal electrical components in the substation, aiming to quantify the seismic vulnerability of the system across different functionality indicators. Finally, the causal inference technique was employed to quantify the importance of various components and equipment. A realistic case study on a typical 220/110/35 kV substation system was performed using the proposed method. The results demonstrate that the method improves the confidence level of the equipment fragility curves, reduces the computational workload of the system vulnerability analysis, and provides a theoretical basis for improving substation performance and formulating post‐disaster maintenance plans. [ABSTRACT FROM AUTHOR]

After an earthquake, legislation tends to permit the rapid demolition of damaged buildings, including the built heritage, for safety reasons, as was the case for many small historic centers after the 2016 earthquake in central Italy. A balance should, of course, be struck between safety and preservation. There must be a willingness to engage in continuous interaction with the various bodies involved in post-earthquake management, particularly in the preventive phase of the complex activities regarding the issues of the seismic vulnerability of historic built. The widespread historical built heritage in Italy requires fast and reliable assessment procedures that allow a large-scale evaluation of the vulnerability of historical buildings before a seismic event. To this end, a proposal is presented here for the inverse use of the protocol for the seismic vulnerability survey of historic centers by means of a system called CARTIS form, coordinated since 2015 by the Italian consortium of Seismic and Structural Engineering Laboratories (ReLUIS). This rapid assessment is compared with an equally fast method for constructing fragility curves, based only on the information available in the ReLUIS–CARTIS database, defining the relationship between the probability of reaching a level of loss of structural safety or a vulnerability index as a function of the seismic acceleration PGA and the ground orography. The methodology outlined could be considered to be progress in cultural heritage diagnostics on a large scale, considering cultural heritage to be the diffuse historical residential masonry buildings that form the historic centers. [ABSTRACT FROM AUTHOR]

There is limited existing research that identifies the optimum rehabilitation strategy, taking utility decision-makers' risk attitudes into account. The objective of this study is to detect the critical pipes of a water distribution network (WDN) for rehabilitation, maximizing the post-earthquake serviceability of the WDN while minimizing the risk of choosing a specific rehabilitation strategy. For that purpose, a multi-objective optimization framework is formulated. System Serviceability Index (SSI) is quantified to represent the serviceability of a WDN after an earthquake. One of the two objective functions in the optimization problem maximizes the expected SSI value. The second objective function minimizes the value at risk (VaR) or conditional value at risk (CVaR) of the decision-making. The solution methodology comprises five steps: pipe seismic repair rate calculation, hydraulic modeling, and analysis, Monte Carlo simulation, nondominated sorting genetic algorithm (NSGA) for optimization, and nondominated or Pareto-optimal rehabilitation strategies identification. The proposed approach is applied to a WDN to demonstrate its effectiveness. The proposed approach offers a range of nondominated or Pareto-optimal rehabilitation strategies facilitating the decision-making based on tradeoffs between post-earthquake serviceability and risk within a specific budget limit. The proposed approach outperforms existing methods by providing risk-averse decision-makers with a set of optimal rehabilitation strategies with known risk levels. [ABSTRACT FROM AUTHOR]

The 2014 Orkney earthquake caused significant damage to unreinforced masonry buildings in the surrounding townships. After the earthquake, field surveys were conducted to assess the extent of damage in the affected areas. This study reviews data collected from the 2014 Orkney earthquake to investigate damage patterns, evaluate building safety for occupancy, and support fragility curve construction. Damage was quantified based on the European Macroseismic Scale (EMS-98) to assess building safety and conduct regression analysis. The results indicate that the collected data is suitable for investigating damage patterns and determining building safety for occupancy. However, it is not suitable for constructing fragility curves. Empirical fragility curves are typically developed using logistic regression, but this study found the data unsuitable for regression analysis due to sampling errors and limited data quantity. This study recommends the use of first-order approximation methods to supplement the dataset, reducing sampling errors and increasing data quantity.

Medieval defensive walls are a distinctive feature of Italian cultural heritage. These structures testify the origins of historical centres and, in some cases, the consequences of the events occurred over time. The typical configuration of medieval defensive walls, generally characterized by high slenderness ratios, out-of-plumb, the absence of deep and adequate foundations, made these elements particularly vulnerable toward seismic actions. This study focused on the assessment of the seismic safety of Italian medieval defensive walls toward out-of-plane failure mechanisms induced by seismic actions. To this end, a simple approach based on the use of generalized dimensionless capacity curves is presented. These curves, derived by the Authors from a calibration process involving a set of selected real cases, allows for a rapid preliminary seismic assessment of masonry walls particularly useful for getting an initial idea of the condition of the walls with respect to seismic actions also considering the presence of pre-existing out-of-plumb configurations. The proposed approach has been applied in the paper to the real case study of medieval walls of Cittadella, a town in northern Italy, considering the pre-existing out-of-plumb configuration. The obtained results have shown the vulnerability of these walls in case of occurrence of masonry disaggregation and, consequently, the importance of performing specific surveys finalized to investigate this phenomenon. The application of the proposed approach has clearly shown its feasibility and usefulness for the seismic evaluation. Moreover, the comparison with the corresponding results obtained by using the actual capacity curves, rather than the generalized ones, has underlined its good level of reliability. [ABSTRACT FROM AUTHOR]

The proposed research work presents a comprehensive approach to assessing the seismic vulnerability of archaeological sites. This approach aims to be a quick and easy-to-use investigation procedure that enables accurate and large-scale evaluations. While the methods employed are well-established in the literature and have been widely applied to buildings, this study contributes by proposing a structured framework that integrates different assessment procedures at different levels of analysis, specifically tailored to archaeological sites. The analysis is divided into three stages within the conceptual framework: (i) the application of the Masonry Quality Index; (ii) seismic vulnerability assessment and prediction of expected damage; and (iii) analysis of individual walls' structural response through strength domain, capacity and fragility curves. Specifically, the study explores and adapts four Vulnerability Index methods, i.e. GNDT, Formisano, Vicente and Ferreira methods, to suit the specific characteristics of archaeological sites. To this end, a simplified procedure is proposed to estimate the conventional strength in the methods' forms. The comparison of the index-based methods is then crucial for critically evaluating the reliability of vulnerability estimations. The paper illustrates the application of this framework through a detailed case study, i.e. the archaeological site of Wupatki Pueblo in Arizona (US), demonstrating its effectiveness in evaluating the seismic risk and defining the vulnerability distribution of the site. Consequently, this approach facilitates the identification of the most sensitive areas, which necessitate further investigation, providing useful outcomes for the decision-making process concerning the conservation and protection of archaeological sites. [ABSTRACT FROM AUTHOR]

A post-tensioned (PT) timber building coupled with dissipative bracing systems is a sustainable seismic-resistant structural system. This system combines desirable qualities of self-centering, energy dissipation, and lightweight timber, which attracts lesser seismic force and contributes to a better resilient system. Despite significant advancement in the provision of these sustainable seismic-resistant timber-based structural archetypes, more study is required to derive a fuller knowledge of the behaviour of these innovative structural systems under a range of ground motion intensities and limited state capacities. Direct displacement-based design, a performance-based design approach, is used for the design of this system, and performance assessment is carried out using nonlinear dynamic analysis. This study investigates the performance of the braced PT frame under different limit state considerations using ground motion records consistent with the NBC 2020 seismic hazard. [ABSTRACT FROM AUTHOR]

The seismic vulnerability assessment of monumental buildings is a complex task. Several uncertainties mine the reliability of evaluations. Within historical buildings, churches appear as particularly vulnerable objects, prone to instabilities and collapse when undergoing seismic loads. Global and local collapse mechanisms related to in plane and out-of-plane response of walls, respectively, are commonly observed in existing masonry buildings subjected to a seismic event. The main cause is the lack of strong connections among orthogonal walls and between walls and floors, which does not allow a global box-type behaviour of the building. This paper shows an approach to evaluate the vulnerability of churches based on a three-step analysis with increasing detail. The first step is a large-scale analysis to be applied to sets of churches, based on a simplified form comparing 28 mechanisms that can be activated by seismic events. The second step is referred to the evaluation of single churches and related, based on a kinematic approach, to the possibility to have out-of-plane mechanisms. The third step is based on the results of numerical models. It is useful to evaluate the behaviour in detail of some macroelements and to validate the obtained results in the first two steps. [ABSTRACT FROM AUTHOR]

In September 2017, two strong earthquakes hit the central region of Mexico, producing substantial damage to the historical buildings. A retroactive analysis for assessing the pre-event seismic vulnerability of these constructions allowed for testing the suitability of an existing parameter-based approach based on material and geometrical features. More than 160 adobe buildings in four municipalities of the State of Morelos were surveyed and included in a vulnerability-oriented GIS database. Data were collected on-site and managed by resorting to open-source GIS software combined with a Python-based database management tool and a cloud-based platform for onsite data collection using mobile devices. The parameter-based approach was used for assessing the analytical seismic vulnerability of the buildings and implementing a secondary, more conservative assessment that considers uncertainties associated with the data acquisition process. The capabilities of the database were further used to train a Machine Learning algorithm aimed at overcoming some representativeness limitations of the parameter-based analytical method. This third approach was found to be suitable for assessing the vulnerability of the building typologies addressed in this investigation. Although the implementation discussed in this paper is limited to a specific vernacular typology, it can be used to conduct customized local calibrations. [ABSTRACT FROM AUTHOR]

This paper presents a combined approach for the seismic vulnerability assessment of pitched portal frames by coupling elastic and limit analysis. Pitched portal frames are widely adopted both in civil and industrial building structures, as well as in architectural heritage structures, including cathedral portal frames in ecclesiastical buildings. The seismic vulnerability assessment of such structures is crucial for mitigating territorial seismic risk. In this study, elastic and limit analyses are adopted and combined to evaluate the seismic capacity of pitched portal frames. To this end, a simplified model is proposed to analyze both linear and non-linear responses of these structures under horizontal actions. Although the analysis focuses on two-dimensional (2D) portal frames, it can be extended to three-dimensional (3D) buildings in a straightforward manner due to the specific characteristics of the analyzed structural scheme. The proposed approach provides a preliminary yet efficient evaluation of the seismic vulnerability of buildings with pitched portal frames. Furthermore, the effectiveness of the proposed procedure ensures valuable applicability in large-scale seismic assessments.

Five existing unreinforced masonry buildings, built in different Italian cities in a relatively recent time frame, were selected to study the seismic behaviour of modern existing structures, not designed to withstand seismic actions. The buildings were modelled using an equivalent-frame approach, adopting, and comparing two nonlinear constitutive laws and introducing specific modelling strategies to represent the distinctive features of modern existing URM structures. Nonlinear static analyses were performed to determine capacity and multi-stripe time history analyses to evaluate displacement demand at increasing return periods. Although non-exhaustive, the results show a trend of generally decreasing seismic vulnerability for more recent buildings. [ABSTRACT FROM AUTHOR]

Seismic vulnerability evaluation of existing buildings is essential to minimize the destructive impacts of earthquakes. Rapid visual screening (RVS) methods are simple and effective vulnerability assessment techniques to help quickly identify high-risk buildings for more detailed evaluations. Among various RVS methods, the Hassan–Sozen priority index (PI) is one of the simplest methods that can be used for low-rise reinforced concrete (RC) buildings. The PI relates simple, easily attainable geometric features of a building including number of stories, floor area, column area, and wall area to damageability. However, the relationship is overly simplified, and there is no absolute basis for defining damage classification boundaries that can be used to interpret the PI. Furthermore, given the lack of seismic parameters as inputs, the PI only allows for a relative evaluation of buildings in a specific region. To address these issues and develop a more broadly applicable RVS method, this study first proposes an improved PI evaluation method using machine learning techniques to define damage classification boundaries. Then, a new generalized RVS method is proposed that considers the PI input features and earthquake intensity measures to predict damage states. Data from six post-earthquake damage surveys (Duzce (1999), Bingol (2003), Nepal (2015), Taiwan (2016), Ecuador (2016), and Pohang (2017)) are used to train and evaluate the classification models. Two earthquake intensity features, modified Mercalli intensity and peak ground acceleration, are introduced to develop a new earthquake intensity aware RVS. The results of the proposed methodologies show a considerable improvement from the original PI with no judgment needed to define the damage classification boundaries. [ABSTRACT FROM AUTHOR]

Cliff-attached structures are structures attached to slopes and connected tightly, which is particularly complex to analyze due to the foundations’ unequal grounding and the lateral stiffness’ irregularity. In rare earthquakes, seismic waves are usually obliquely incident on the foundation at a certain angle. Therefore, it is not appropriate to consider only seismic waves’ vertical incidence, and it is necessary to consider multi-angle oblique incidence. In this paper, based on the theory of viscous-spring artificial boundary and the principle of equivalent nodes at the interface of oblique incidence of ground shaking P-waves, and combined with the dynamic properties related to Buckling-Restrained Brace, the numerical models of slopes and two kinds of cliff-attached structures considering the slope amplification effect and soil-structure interaction are established. The dynamic response of the obliquely incident seismic waves under the action of the cliff-attached vibration reduction structure is studied in depth, and the additional effective damping ratios of the nonlinear energy-dissipated units based on the deformation energy are compared and analyzed. It is shown that under the four oblique incidence angles of incidence (compression waves in the vertical plane) studied in this paper, the seismic dynamic response and damage degree peaked at an angle of incidence of 60°, with a tendency to increase and then decrease with increasing angles of incidence. The ability of an energy-dissipating vibration reduction device to change structural vibration characteristics decreases with an increase in incidence angle. The difference between the total strain energy of the structure in the X-direction (Transverse slope direction) and Y-direction (Down-slope direction) and the total energy dissipation of the dissipative components is obvious, with the X-direction being about 10 times that of the Y-direction.

This study discusses the effects of local sites and hazard amplification on the seismic vulnerability assessment of existing masonry buildings. In this context, a rapid seismic evaluation procedure was implemented on an old masonry building stock in the historical center Galata, located in Istanbul, to determine the seismic risk priority of the built heritage. Damage scenarios were generated for all soil classes, different moment magnitudes, and source-to-site distances to obtain more accurate results for the seismic vulnerability assessment of the studied building stock. Consequently, damage distributions estimated under nine different scenarios with/without site effects were compared and illustrated in maps to discuss changes in vulnerability owing to amplification effects. In this study, by re-examining the rapid seismic evaluation procedure by including geo-hazard-based assessment, the importance of site effects on the vulnerability and risk assessment of built heritage was underlined. The proposed framework integrating field data and local site effects is believed to advance the current applications for vulnerability assessment of masonry buildings and provide an improvement in the application of rapid seismic assessment procedures with more reliable results. [ABSTRACT FROM AUTHOR]

The Philippine General Hospital (PGH) is a tertiary hospital in Ermita, Manila, that was founded on August 17, 1907. It adheres to the philosophy of providing all Filipinos with internationally competitive, cost-effective, compassionate, and accessible health care. It was recently one of the COVID-19 facilities. The PGH sits 9.2 kilometers east of the West Valley Fault, making it more vulnerable to 'The Big One,' a 7.2 magnitude earthquake. Until present, no research has been done to examine the PGH's seismic susceptibility in the case of a large-magnitude earthquake. In keeping with this, the study intended to analyze the seismic susceptibility of the Spine Building, one of PGH's oldest structures. It focused on constructing fragility curves to assess if the building could sustain a 0.4g peak ground acceleration (PGA) earthquake with a maximum likelihood of exceedance of 10%, as required by the Philippine National Structural Code (NSCP) for Seismic Zone 4 sites. The study employed 12 worldwide and 12 local earthquakes from the Incorporated Research Institutions for Seismology, with PGA excitation levels ranging from 0.1g to 3.0g (with a 0.1g gap) (IRIS). The structural model of the PGH Spine Building was created using SAP2000, which was subsequently utilized to perform Pushover Analysis using the Capacity Spectrum Method (CSM). The PGH Spine Building might collapse with 0.538g PGA, which corresponds to Intensity VIII, according to the results of the developed fragility curves, producing significant structural shaking. Furthermore, for 0.4g PGA, the calculated highest likelihood of exceedance in the 'collapse damage' condition was 5.24 percent, with no results above 10%, implying that the PGH Spine Building complies with the NSCP seismic requirement for structures located in Seismic Zone 4. As a result, an adequate retrofitting strategy is not required for the PGH Spine Building.

This study evaluates the seismic behavior of reinforced concrete buildings with plan and vertical irregularities. Indeed, for their functional and aesthetic advantages, architects are increasingly adopting designs combining irregularity in plan and elevation. However, these irregularities increase the sensitivity of the structures to the torsion phenomenon. This article examines the influence of building irregularities on the seismic behavior of these structures by comparing their performance characteristics to those of a defined regular reference structure. Four three-dimensional models of RC shear moment frame buildings, having the same basic design but presenting different plan and elevation geometric irregularities, have been studied using the nonlinear static method in order to deduce and compare their behavior with respect to seismic excitation. Comparing the capacity diagrams has demonstrated a large decrease in the seismic performance of structure with the presence of geometric irregularity. This decrease is even more significant with the combination of the two types of irregularity. [ABSTRACT FROM AUTHOR]

The evaluation of the seismic vulnerability of existing buildings is becoming very significant nowadays, especially for ancient masonry structures, that represent the cultural and historical heritage of our countries. In this research, the Cathedral of Santa Maria Assunta in Catanzaro (Italy) is analyzed to evaluate its structural response. The main physical properties of the constituent materials were deduced from an extensive diagnostic campaign, while the structural geometry and the construction details were derived from an accurate 3D laser scanner survey. A global dynamic analysis, based on the design response spectrum, is performed on a finite element model for studying the seismic response of the structure. Moreover, a local analysis is conducted to evaluate the safety factors corresponding to potential failure mechanisms along preassigned failure surfaces. Furthermore, pushover analyses are performed on macro-elements, properly extracted from the whole structure and with an independent behavior with regard to seismic actions. A novel model based on inter-element fracture approach is used for the material nonlinearity and its results are compared with a well-known classical damage model in order to point out the capability of the method. Finally, the results obtained with the three different models are compared in terms of seismic vulnerability indicators.

Reinforced concrete (RC) structures located in aggressive environment, for example, RC bridge piers close to the sea and experiencing chloride attacks, may be exposed to an increased seismic vulnerability. This requires practical yet effective safety assessment strategies aimed to determine the seismic behavior by incorporating corrosion deterioration phenomena. An easy‐to‐use phenomenological model is here developed to describe the seismic behavior of corroded RC elements based on a fiber hinge formulation wherein the corrosion‐induced mechanical degradation of concrete and steel is implemented through appropriate constitutive laws at the fiber level. The developed fiber hinge formulation is first validated against experimental cyclic tests of corroded RC columns from the literature. Then, the proposed approach is used for the seismic vulnerability assessment of the Zappulla multi‐span viaduct (southern Italy), whose RC bridge piers (with a box‐shaped, two‐cell hollow rectangular cross section) are exposed to carbonation and chloride‐induced corrosion. A comprehensive in‐situ testing campaign is conducted for the mechanical characterization of the materials in the RC piers. Corrosion potential mapping, carbonation tests and tensile tests on corroded bars extracted from RC piers are critically interpreted to calibrate the constitutive laws of the fiber‐hinge model. Motivated by experimental findings, numerical seismic analyses (including linear dynamic, nonlinear static and nonlinear dynamic analyses) are performed under two different corrosion scenarios to quantify the impact of corrosion on the resulting seismic vulnerability conditions of bridge piers with corroded bars. The proposed approach is characterized by low computational cost and lends itself to large‐scale seismic vulnerability assessment of other existing RC bridges placed in corrosive environment. [ABSTRACT FROM AUTHOR]

The paper describes a novel Adriseismic method for expeditious assessment of seismic risk associated with unreinforced masonry buildings. The methodology was developed for the Adriseismic project of the Interreg ADRION programme, with the aim to develop and share tools for increasing cooperation and reducing seismic risk for six participating countries within the region surrounding the Adriatic and the Ionian Seas. The method is applicable to unreinforced masonry buildings characterised by three main seismic failure mechanisms, namely masonry disintegration, out-of-plane failure, and in-plane damage/failure. Depending on the input parameters for a specific structure, the assessment yields a qualitative output that consists of the masonry quality index, the index of structural response, the level of seismic risk, and the most probable collapse mechanism. Both input and output of the method are applied in the spreadsheet form. The method has so far been applied in urban areas of participating countries in the project, including Mirandola, Italy; Kaštela, Croatia; Belgrade, Serbia. In parallel, the methodology has been validated by performing a detailed seismic assessment of more than 25 buildings, and the results have been compared with the results of the proposed expeditious method. The results show a good correlation between the two methods, for example, the structural response index obtained from the expeditious method and the capacity/demand ratio obtained from the conventional assessment method. [ABSTRACT FROM AUTHOR]

This paper describes the implementation of a comprehensive strategy for the structural typification of historical buildings located in earthquake-prone regions using digital technologies such as HBIM and Augmented Reality. The paper starts by presenting a detailed analysis of a selected sample of case studies in Peru in which key structural and architectural features were identified, aiming at proposing a preliminary typological classification. This typification was then optimized by analyzing its application in a larger data set consisting of 311 churches located in the Central Andes region. This allowed formalizing 12 structural typologies, which demonstrated to have the potential to provide an accurate description of the geometrical, material, and structural characteristics of Andean churches. The paper underlines the importance of combining digital technologies and comprehensive engineering analyses for creating tools that will facilitate further structural evaluations and seismic vulnerability assessments at a territorial scale. For the study, these tools improved information management processes, analyses, and post-processing tasks, and facilitated communication and decision-making among stakeholders. [ABSTRACT FROM AUTHOR]

The Philippine General Hospital (PGH) is a tertiary hospital in Ermita, Manila, that was founded on August 17, 1907. It adheres to the philosophy of providing all Filipinos with internationally competitive, cost-effective, compassionate, and accessible health care. It was recently one of the COVID-19 facilities. The PGH sits 9.2 kilometers east of the West Valley Fault, making it more vulnerable to 'The Big One,' a 7.2 magnitude earthquake. Until present, no research has been done to examine the PGH's seismic susceptibility in the case of a large-magnitude earthquake. In keeping with this, the study intended to analyze the seismic susceptibility of the Spine Building, one of PGH's oldest structures. It focused on constructing fragility curves to assess if the building could sustain a 0.4g peak ground acceleration (PGA) earthquake with a maximum likelihood of exceedance of 10%, as required by the Philippine National Structural Code (NSCP) for Seismic Zone 4 sites. The study employed 12 worldwide and 12 local earthquakes from the Incorporated Research Institutions for Seismology, with PGA excitation levels ranging from 0.1g to 3.0g (with a 0.1g gap) (IRIS). The structural model of the PGH Spine Building was created using SAP2000, which was subsequently utilized to perform Pushover Analysis using the Capacity Spectrum Method (CSM). The PGH Spine Building might collapse with 0.538g PGA, which corresponds to Intensity VIII, according to the results of the developed fragility curves, producing significant structural shaking. Furthermore, for 0.4g PGA, the calculated highest likelihood of exceedance in the 'collapse damage' condition was 5.24 percent, with no results above 10%, implying that the PGH Spine Building complies with the NSCP seismic requirement for structures located in Seismic Zone 4. As a result, an adequate retrofitting strategy is not required for the PGH Spine Building. [ABSTRACT FROM AUTHOR]

Despite the fact that in recent years Portugal has not seen the occurrence of high-magnitude earthquakes, it remains threatened by these events due to its geographic location. Since the 1960s, reinforced concrete has been the most used material for new constructions; however, the historic urban centers are dominated by old unreinforced masonry (URM) buildings, which techniques and construction materials have evolved since the Great Lisbon earthquake that occurred in 1755 (Mw = 8.5). Given the presence of these buildings in areas of significant seismicity, extensive research is needed to assess the seismic risk and define mitigation policies. This kind of studies is often supported by empirical methods and based on expert judgment due to the high variability of the building stock and lack of information. The main purpose of this work is: (i) to provide analytical fragility curves, supported by nonlinear static analysis, for the entire population of old masonry buildings, built before the introduction of the first design code for building safety against earthquakes (RSSCS) in 1958; (ii) define vulnerability curves to be used by the technical community for seismic assessment of pre code URM buildings. The characterization of the building stock geometry and material properties is based on information previously collected, which was essential to define representative archetypes and typologies. [ABSTRACT FROM AUTHOR]

Historic buildings are the cultural and traditional identity of a country. However, these buildings are vulnerable to earthquakes because of their aged structure, poor maintenance, and inadequate structural health monitoring. Therefore, seismic vulnerability assessment is a critical aspect in the restoration and retrofitting of heritage buildings. In this study, a comprehensive survey was performed to collect the data of old and historic church buildings in and around the twin cities of Bhubaneswar and Cuttack in Odisha for evaluating the performance of these structures against seismic activity. The macroelemental method for seismic vulnerability assessment was used to calculate the seismic vulnerability index of church buildings. The probable damage was estimated based on the obtained values of the mean damage grade according to the EMS-98 scale and were compared with the grade of damageability acquired using the rapid visual screening method for Indian conditions. Damage probability matrices were constructed to determine the probabilistic future damage. This study identified church buildings that require immediate renovation and retrofitting.

Although Portugal has not been hit by high‐magnitude earthquakes in recent years, its history is marked by tragic seismic events and it remains susceptible due to its geographical location. The Portuguese building stock is constituted approximately by 45% masonry residential buildings and most were built before the enforcement of the first seismic code in 1958. For several years, structural interventions in these buildings were allowed without the need to assess their seismic vulnerability. In 2019, a new law was approved to regulate the rehabilitation interventions to provide safety and comfort of existing buildings. The seismic assessment of existing buildings became mandatory and based on the procedures and requirements included in NP EN 1998–3: 2017 (Portuguese version of Eurocode 8 – part 3), which establishes the performance requirements and compliance criteria for existing buildings subjected to a certain level of seismic action. According to this normative requirements, analytical seismic vulnerability assessment and reliability‐based analyses were carried out on a large set of masonry buildings representative of the Portuguese housing stock, leading to the development of surrogate and expeditious method for seismic assessment in compliance with the reference method defined in the European standard. The method allows the seismic assessment of masonry buildings with rigid and flexible floors, without explicit numerical analyses, using only geometric parameters and the material properties. Compliance of results assessed by the proposed method and the corresponding values obtained by the code were carried out by confidence tests. [ABSTRACT FROM AUTHOR]

The Lisbon earthquake occurred in 1755, which affected Morocco seriously, provoked the collapse of the Triumphal arch of Caracalla in Volubilis. The currently visible monument is the result of the rebuilding carried out in 1930 by French restores. In this paper, the timeline of collapses caused by the subsequent seismic quakes is retraced aimed at estimating the lower bound of the intensity of the 18th century earthquake, based on structural investigations carried out on rigid-block and continuous FE models. The historical investigations and the digital survey carried out by the authors in 2017 served as the base of knowledge to drive the analyses. Results of the analyses of the two models are very comparable and provide that a low acceleration of 0.168 g was sufficient to provoke the collapse of the arch and explain the reason why the expected earthquake acceleration in the zone of the archaeological site of Volubilis provided by the current Moroccan seismic code is exactly 0.16 g. Therefore, with the purpose of assessing also the current seismic vulnerability of the arch, this result leads to state that the capacity is equal to the seismic demand, and, therefore, too low to ensure the safety in the case of un unexpected event. [ABSTRACT FROM AUTHOR]

Historic urban centers characterised by traditional masonry aggregate patio houses have been studied under many aspects: the patio construction type allows to obtain thermal conditions suitable for particular climatic conditions and introverted interior spaces suitable for specific cultures. Conversely, the seismic vulnerability assessment is not yet thoroughly investigated. This paper proposes a methodology for the seismic vulnerability assessment at the urban scale for traditional masonry aggregate patio houses, developing on Vulnerability Index approach combined with the macroseismic method through vulnerability functions. In particular, an appropriate survey form is proposed by a thorough calibration on the remarkable case study of the Fes medina, UNESCO World Heritage site, which has suffered severe damages from earthquakes occurred in ancient time. The study allowed to realise vulnerability and fragility curves, damage scenarios, and loss scenarios. The method was applied a second time to the case study after simulated structural retrofitting interventions. The vulnerability assessment results are also presented through maps with the Geographic Information System (GIS). [ABSTRACT FROM AUTHOR]

The present study proposes a statistical methodology to rate the habitability of different types of buildings after an earthquake. The first step was to rank variables that affect the vulnerability of a building and formulate a statistical study with a discrimination index that makes it possible to identify buildings as habitable or non-habitable. This ranking applied the criteria established in various international guidelines that are used to distinguish between habitable (undamaged/no structural damage) and non-habitable buildings (structural damage). The proposed methodology was applied to a database with information about buildings and damage grade experienced following the 2011 earthquake in Lorca. The approach presented could be extended to other regions where neccessary data are available. [ABSTRACT FROM AUTHOR]

The evaluation of the seismic vulnerability of existing buildings is becoming very significant nowadays, especially for ancient masonry structures, that represent the cultural and historical heritage of our countries. In this research, the Cathedral of Santa Maria Assunta in Catanzaro (Italy) is analyzed to evaluate its structural response. The main physical properties of the constituent materials were deduced from an extensive diagnostic campaign, while the structural geometry and the construction details were derived from an accurate 3D laser scanner survey. A global dynamic analysis, based on the design response spectrum, is performed on a finite element model for studying the seismic response of the structure. Moreover, a local analysis is conducted to evaluate the safety factors corresponding to potential failure mechanisms along preassigned failure surfaces. Furthermore, pushover analyses are performed on macro-elements, properly extracted from the whole structure and with an independent behavior with regard to seismic actions. A novel model based on inter-element fracture approach is used for the material nonlinearity and its results are compared with a well-known classical damage model in order to point out the capability of the method. Finally, the results obtained with the three different models are compared in terms of seismic vulnerability indicators. [ABSTRACT FROM AUTHOR]

Steel racking systems are civil engineering structures used to store goods and materials before their distribution to the public. In order to serve different logistic needs, a variety of rack typologies with different uses and salient characteristics has evolved over time. As a result, racks can range from large independent buildings in the form of the Automated Rack Supported Warehouses, down to compact sub-structures, or even smaller-scale shelves contained in warehousing units. Still, in all their incarnations they represent significant capital investment in terms of structure and stored goods in need of assessment. Despite their differences in terms of usability and functionality, racking structures share common macro-characteristics that can be summarized in a flexible and collapsible taxonomy, providing the risk analyst with sufficient identification to develop exposure and seismic vulnerability models. The proposed taxonomy adopts the same terminology as the Building Taxonomy of the Global Earthquake Model, comprising five basic classes or Attributes, capable of characterizing any existing, contemporary and upcoming rack typology. [ABSTRACT FROM AUTHOR]

European countries are affected by various levels of seismic hazard, including many areas with medium to high seismicity. Heavy damage over large areas has been observed in past earthquakes in these countries, particularly in masonry buildings located in historical centers, confirming the need for enhancing the current knowledge on the seismic vulnerability of these constructions, so more informed technical and political decisions towards the mitigation of the risk can be taken. However, the characterization of building stocks for engineering purposes is still an open issue due to the enormous amount of resources that such a project would require. Nevertheless, the availability of virtual images and maps represents an outstanding opportunity for having remote approaches to urban environments. The role of on-site inspections can be complemented or even substituted by means of these remote approaches, provided it is complemented with suitable approaches. The use of these resources is not new, but the critical assessment of their capabilities and limitations deserves a critical discussion. The present paper aims at assessing the opportunities offered by web-based mapping platforms in the context of seismic vulnerability assessment of masonry buildings in old urban areas. After evaluating the advantages and shortcomings of some of the most popular web-based mapping services, an explanatory application to a set of 39 buildings located in the historic center of the city of Leiria (Portugal) is presented and critically discussed, contrasting the results obtained by using on-site and remote inspections. Two different seismic vulnerability assessment approaches are applied and analyzed herein, confirming that web-based mapping platforms can represent an efficient and cost-effective complement to traditional field surveys when the large-scale seismic vulnerability of old urban areas is of interest. [ABSTRACT FROM AUTHOR]

Aiming at protecting the vernacular heritage located in earthquake prone areas, the paper presents the development and validation of the numerical tool that constitutes the core of a novel seismic vulnerability assessment method: Seismic Assessment of the Vulnerability of Vernacular Architecture Structures (SAVVAS). An extensive numerical modeling campaign was carried out to evaluate and quantify the influence of several parameters on the seismic response of vernacular buildings. The results were compiled into a database on which regression analysis could be performed to extract correlations between seismic capacity and qualitative and simple quantitative data that can be obtained from visual inspection. [ABSTRACT FROM AUTHOR]

The seismic vulnerability assessment of buildings in historic city centres is the first step to mitigate the possible damage, to prevent heritage losses and to preserve their historical identity. In this paper, the analysis is focused on the residential buildings of "Ground Zero Area" in El Cabanyal. This unique quarter of Valencia, once a fishermen's settlement, has a strong village-like identity and heritage value. Swallowed up by an expanding city centre and threatened by a poor redevelopment plan, which caused its degradation, its rehabilitation is nowadays the object of a new protection plan. The seismic vulnerability of the residential buildings has been assessed using the Vulnerability Index Method, obtaining a global damage index, and the equivalent built area expected to be destroyed. Results, implemented in a GIS environment, revealed that, due to the high vulnerability, many of the analysed listed buildings will be significantly damaged. A new detailed analysis is recommended, to define intervention and retrofitting criteria to improve their seismic response, preserving the architectural heritage and defending the unique identity of El Cabanyal. [ABSTRACT FROM AUTHOR]

Operation of critical infrastructure facilities such as hospitals, firefighting stations, and disaster shelters are critical during a postearthquake scenario. The serviceability of many such facilities is, in turn, dependent on the proper operation of water-supply systems providing water to these facilities. Due to such dependency of disaster relief systems on water supply, having a resilient water-supply system is even more critical in a postearthquake scenario as compared to a normal operating condition. Extant pertinent literature ignores spatial variabilities of the water demand priorities. It assumes that the water demand originating from critical facilities, such as hospitals and the water demand originating from less critical facilities such as golf courses and temporary storage facilities, are of equal importance. This oversimplification has made existing models practically limited, especially in a postearthquake scenario. The objective of this study is to create a methodology to identify optimized proactive seismic rehabilitation policy for water pipe networks considering spatial variabilities of demand criticalities and seismic ground motion intensities. A novel approach based on proximity analysis was created to determine the criticality of each node where the criticality was established based on the spatial distribution of water demand type in the neighborhood of the node. The spatial variabilities of demand criticalities along with the spatial variabilities of the seismic ground motion intensities integrated into the formulation of a stochastic combinatorial optimization problem to identify economical rehabilitation policies for enhancing seismic resilience of the water-supply network. A purpose-built simulated-annealing algorithm integrated with Monte Carlo simulation was then used to solve the optimization problem. A city-scale water pipe network was used as a testbed to demonstrate the effectiveness of the created methodology. The results of this study and their comparison with results from existing methods showed that the created methodology was highly effective in identifying economical proactive seismic rehabilitation policies for preventive intervention when the rehabilitation budget is limited. Furthermore, the results showed that the consideration of spatial variability in water demand type leads to the identification of rehabilitation policies that ensure higher postearthquake serviceability in nodes supplying water to critical facilities. [ABSTRACT FROM AUTHOR]

The paper describes a novel Adriseismic method for expeditious assessment of seismic risk associated with unreinforced masonry buildings. The methodology was developed for the Adriseismic project of the Interreg ADRION programme, with the aim to develop and share tools for increasing cooperation and reducing seismic risk for six participating countries within the region surrounding the Adriatic and the Ionian Seas. The method is applicable to unreinforced masonry buildings characterised by three main seismic failure mechanisms, namely masonry disintegration, out-of-plane failure, and in-plane damage/failure. Depending on the input parameters for a specific structure, the assessment yields a qualitative output that consists of the masonry quality index, the index of structural response, the level of seismic risk, and the most probable collapse mechanism. Both input and output of the method are applied in the spreadsheet form. The method has so far been applied in urban areas of participating countries in the project, including Mirandola, Italy; Kaštela, Croatia; Belgrade, Serbia. In parallel, the methodology has been validated by performing a detailed seismic assessment of more than 25 buildings, and the results have been compared with the results of the proposed expeditious method. The results show a good correlation between the two methods, for example, the structural response index obtained from the expeditious method and the capacity/demand ratio obtained from the conventional assessment method.

Collapse of, or severe damage to, existing buildings during strong earthquakes has resulted in significant economic losses, severe injuries, and casualties. Progress made over the last few decades has had a considerable impact on the seismic safety of modern buildings designed according to new standards. However, the majority of existing buildings in southern European countries do not meet the safety requirements set by the Eurocodes. Thus, the assessment of existing buildings not designed with modern codes and the development of effective retrofitting techniques are currently of paramount importance to society. The use of accurate modelling strategies and appropriate seismic assessment methodologies is crucial to understand the behaviour of existing buildings and to develop efficient and proper mitigation measures, thus, preventing future damage, casualties, and economic losses. The effect of non-structural elements should not be neglected, since they could play a vital role in buildings’ structural performance. Another major challenge is to ensure the sustainability of renovation schemes in terms of both the environmental burden (i.e., CO2) and economic investment in seismic regions. The sustainable renovation of existing buildings typically focuses on reducing operational energy consumption and using low-carbon materials in the refurbishment process, without accounting for structural deficiencies that could leave the building exceptionally unsafe and hamper the refurbishment investment, particularly in areas prone to seismic activity. This Special Issue focuses on innovations in the context of assessment and retrofitting of building structures: experimental testing and modelling.

The recent discovery of a Thermopolis in Regio V of the archaeological site of Pompeii in December 2020, still completely intact and complete with decorations and kitchenware, has recalled the important role of archaeological sites that preserve and pass on the historical, artistic and architectural value of populations. Therefore, it appears even more evident, that there is the need to identify suitable methodologies to preserve intact the archaeological heritage, consistent with their peculiar characteristic of being in a state of ruin and, therefore, even more vulnerable to external actions, such as those induced by an unexpected earthquake, as compared to a complete building. Moreover, the very fact of being a protected heritage, also necessarily requires the use of special interventions such as not to alter the structures themselves and to guarantee reversibility. In this context, in this paper the seismic vulnerability of the remains of the colonnade of the forum of Pompeii is evaluated with the methods of kinematic analysis that allows the identification of the collapse mechanisms activated by an earthquake. To increase the capacity to withstand seismic actions, a non-invasive, reversible and non-impact reinforcement system has been proposed and validated carrying out numerical analyses conducted by means of a calculation code developed specifically for the study of these structural types consisting of an assemblage of rigid blocks. [ABSTRACT FROM AUTHOR]

The city of Vila Real de Santo António (VRSA) was erected after the 1755 Lisbon earthquake following a Pombaline development similar to the well-known reconstruction of Lisbon downtown. It included seismic-resistant measures at an urban and architectural level, but most original buildings have nowadays been replaced or are highly altered. A research question arises whether or not and to what extent these alterations have compromised the seismic vulnerability of the historical city center. The paper presents the seismic vulnerability assessment of the historic city center of VRSA using a newly developed method: Seismic Assessment of the Vulnerability of Vernacular Architecture Structures (SAVVAS). The method proposes a numerical tool intended to estimate the seismic capacity of vernacular buildings using qualitative and simple quantitative data that can be rapidly obtained from visual inspections. The seismic vulnerability and loss assessment consider different scenarios, including the historical condition, and studies different retrofitting strategies. [ABSTRACT FROM AUTHOR]