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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]

Seismic bands are frequently employed as an earthquake-resilient technique to enhance the performance of random rubble (RR) stone masonry buildings. This study quantifies the effect of five possible scenarios of roof diaphragms in RR stone masonry along with the seismic bands at roof, lintel, and sill levels and stitch bands at corners under seismic forces. A single-story school building is numerically modeled through finite element analysis adopting the macro modeling technique. The stone masonry building is investigated for static as well as dynamic loading by performing pushover and time-history analysis. Spectrum-matched ground motions are considered to perform the incremental dynamic analysis (IDA) and the fragility curves of RR stone masonry buildings are generated with four defined damage states. The base shear capacity of an RR stone masonry building with wooden roof and seismic bands at the roof and lintel level has shown a notable increase of 73%. The insertion of stitch bands in between the lintel and sill level at the corner and T-junction of walls of the building has reduced the vulnerability of the building at various damage states. The obtained results highlight that at maximum credible earthquake (peak ground acceleration = 0.36 g), the probability of near collapse of stone masonry having a wooden roof with two and four bands is reduced by 70% and 90%, respectively, as compared to buildings without bands. The study signifies the importance of horizontal bands in providing the desirable seismic performance for building with diaphragms and also for building with negligible diaphragm contribution. [ABSTRACT FROM AUTHOR]

This study presents a novel framework for integrating corrosion effects into critical infrastructure seismic risk assessment, focusing on reinforced concrete (RC) structures. Unlike traditional seismic fragility curves, which often overlook time-dependent degradation such as corrosion, this methodology introduces an approach incorporating corrosion-induced degradation into seismic fragility curves. This framework combines time-dependent corrosion simulation with numerical modeling, using the finite–discrete element method (FDEM) to assess the reduction in structural capacity. These results are used to adjust the seismic fragility curves, capturing the increased vulnerability due to corrosion. A key novelty of this work is the development of a comprehensive risk assessment that merges the corrosion-adjusted fragility curves with seismic hazard data to estimate long-term seismic risk, introducing a cumulative risk ratio to quantify the total risk over the structure's lifecycle. This framework is demonstrated through a case study of a one-story RC moment frame building, evaluating its seismic risk under various corrosion scenarios and locations. The simulation results showed a good fit, with a 3% to 14% difference between the case study and simulations up to 75 years. This fitness highlights the model's accuracy in predicting structural degradation due to corrosion. Furthermore, the findings reveal a significant increase in seismic risk, particularly in moderate and intensive corrosion environments, by 59% and 100%, respectively. These insights emphasize the critical importance of incorporating corrosion effects into seismic risk assessments, offering a more accurate and effective strategy to enhance infrastructure resilience throughout its lifecycle. [ABSTRACT FROM AUTHOR]

In Almaty, the largest city in Kazakhstan lying on a high seismic region, many residential buildings constructed during the Soviet Union are still in service. These buildings were not properly designed against earthquakes and special seismic detailing was not well considered according to the local design code. Therefore, this paper presents an analytical seismic assessment of two typical reinforced concrete moment frame residential structures constructed in this era, representing 812 buildings with almost identical construction materials, geometries, and structural details. Two-dimensional nonlinear models were developed for these buildings in each orthogonal direction based on the structural details collected from a Kazakh government agency. Incremental dynamic analyses were then performed using 24 historical strong ground motions with fault characteristics similar to those in the Almaty region. Structural global and local seismic responses were investigated. A new approach was proposed to define structural global inter-story drift limits at different damage states based on local seismic demands considering uncertainties of earthquakes and structural nonlinear dynamic responses. Based on these inter-story drift limits, the structural fragility curves were then developed to identify the damage probability of these buildings, which were further used to roughly estimate repair costs at different earthquake intensity levels. It has been found that these buildings are vulnerable to destructive earthquakes due to poor structural details. They possess a high probability of incurring extensive damage (high repair cost) or even collapsing (irreparable) at the earthquake intensity level, with a return period of 475 years or 2475 years, respectively. [ABSTRACT FROM AUTHOR]

Strong seismic events frequently strike Chile. The last three significant events that caused considerable damage and losses are the 2010 ( M w 8.8, Maule), 2014 ( M w 8.2, Iquique), and 2015 ( M w 8.3, Illapel) earthquakes. Therefore, reliable fragility curves are necessary to evaluate the threat of earthquakes to the built environment. This study aims to develop empirical fragility curves of Chilean houses using damage from the 2014 and 2015 earthquakes. The data from 9085 and 7431 damaged houses from the 2014 and 2015 earthquakes, respectively, was obtained by the government. The fragility curves were estimated for reinforced concrete, reinforced masonry, timber, and adobe houses. Additionally, the fragility curves were constructed using three different Peak Ground Acceleration (PGA) maps to quantify the variation of the fragility parameters based on the selected PGA map and to identify which PGA map generates the highest correlation with observed damage. Additionally, fragility curves obtained in this study are compared with curves from other studies. The median θ values of the fragility curves obtained in this study are larger than those from other reported studies. [ABSTRACT FROM AUTHOR]

This paper proposes a mathematical framework for optimal retrofit and recovery strategies of bridge networks. The pre-earthquake and postearthquake management of the highway systems is addressed considering performance objectives based on seismic resilience and life-cycle costs. Structural capacity of vulnerable bridges and traffic performance of the transportation network are investigated accounting for the effects of aftershocks by state-dependent fragility curves informing cumulative damage scenarios. Optimal intervention sequences are identified under uncertainties related to bridge damage levels and mainshock–aftershock sequences based on a biobjective optimization problem aiming to maximize network resilience and minimize costs associated with pre-event retrofit and postrepair restoration activities. [ABSTRACT FROM AUTHOR]

Irregular reinforced concrete framed buildings are peculiar and their seismic response is difficult to predict using simplified approaches. The irregularity in structural configuration is characterized by cross-sectional area reduction of the columns along the height, in-elevation and in-plan irregular distribution of the masses, complex floor geometry or floor geometry variation along the height. This study analyses the seismic response of several four-storey buildings with different types of irregularities, namely in-elevation floor height and floor geometry variation. Additionally, responses of both seismically designed and gravity load designed structures are compared for each geometry considered. A numerical model accounting for non-linear flexural and shear response of the structure is developed, aimed at conducting non-linear incremental dynamic analyses. The results are discussed in terms of inter-storey drift, floor acceleration profiles, fragility functions and floor response spectra. A significant influence of the irregularity on floor accelerations and displacements was observed, as well as on the spectral acceleration at collapse, mainly caused by mass and stiffness variation along the height. On the other hand, no significant influence was detected on failure modes. [ABSTRACT FROM AUTHOR]

This article presents the derivation of a fragility model for the Italian masonry school building asset, comprising 265 sets of fragility curves for as many building types, classified on the basis of few parameters: construction age, number of stories, plan area, and type of masonry (i.e. with regular or irregular pattern). The fragility assessment was carried out by means of parametric analyses, generating more than 7500 samples which were then analyzed through the mechanics-based procedure Vulnus. Sample fragilities were then linearly combined to obtain fragility curves consistent with the adopted taxonomy based on few parameters. A macroseismic–heuristic model from the literature was used to extend the fragility model to five damage states, according to the European Macroseismic Scale (EMS98). The proposed model was compared to empirical information in terms of observed damage on three existing schools and fragility curves recently derived by processing data of school damaged by the 2009 L'Aquila earthquake, showing a satisfactory agreement. In addition, a comparison with fragility sets for residential buildings was carried out. Both fragility models were developed with the same procedure, so as to point out differences between schools and ordinary buildings. Similar fragilities were observed for schools and residential buildings built before 1945, whereas for later periods, schools showed a higher fragility than the residential asset. Finally, seismic damage maps were developed at national scale showing the distribution of expected damage as a possible application of the derived model. [ABSTRACT FROM AUTHOR]

This study assesses physical infrastructure vulnerability for infrastructure network components exposed during the 2015 Illapel tsunami in Coquimbo, Chile. We analyse road and utility pole vulnerability to damage, based on interpolated and simulated tsunami hazard intensity (flow depth, flow velocity, hydrodynamic force and momentum flux) and network component characteristics. A Random Forest Model and Spearman's Rank correlation test are applied to analyse variable importance and monotonic relationships, with respect to damage, between tsunami hazards and network component attributes. These models and tests reveal that flow depth correlates higher with damage, relative to flow velocity, hydrodynamic force and momentum flux. Scour (for roads and utility poles) and debris strikes (for utility poles) are strongly correlated with damage. A cumulative link model methodology is used to fit fragility curves. These fragility curves reveal that, in response to flow depth, Coquimbo roads have higher vulnerability than those analysed in previous tsunami event studies, while utility poles demonstrate lower vulnerability than with previous studies. Although we identify tsunami flow depth as the most important hydrodynamic hazard intensity metric, for causing road and utility pole damage, multiple characteristics correlate with damage and should also be considered when classifying infrastructure damage levels. [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.

Records of wave-induced damage on coastal bridges during natural hazards have been well documented over the past two decades. It is of utmost importance to decipher the loading mechanism and enhance the resilience of coastal bridges during extreme wave-inducing events. Quantification of vulnerability of these structures is an essential step in designing a resilient bridge system. Recently, considerable efforts have been made to study the force applied and the response of coastal bridge systems during extreme wave loading conditions. Although remarkable progress can be found in the quantification of load and response of coastal superstructures, very few studies assessed coastal bridge resiliency against extreme wave-induced loads. This paper adopts a simplified and practical technique to analyze and assess the resilience of coastal bridges exposed to extreme waves. Component-level and system-level fragility analyses form the basis of the resiliency analysis where the recovery functions are adopted based on the damage levels. It is shown that wave period has the highest contribution to the variation of bridge resiliency. Moreover, this study presents the uncertainty quantification in resiliency variation due to changes in wave load intensity. Results show that the bridge resiliency becomes more uncertain as the intensity of wave parameters increases. Finally, possible restoration strategies based on the desired resilience level and the attitude of decision-makers are also discussed.

We have proposed a methodology to assess the robustness of underground tunnels against potential failure. This involves developing vulnerability functions for various qualities of rock mass and static loading intensities. To account for these variations, we utilized a Monte Carlo Simulation (MCS) technique coupled with the finite difference code FLAC3D, to conduct two thousand seven hundred numerical simulations of a horseshoe tunnel located within a rock mass with different geological strength index system (GSIs) and subjected to different states of static loading. To quantify the severity of damage within the rock mass, we selected one stress-based (brittle shear ratio (BSR)) and one strain-based failure criterion (plastic damage index (PDI)). Based on these criteria, we then developed fragility curves. Additionally, we used mathematical approximation techniques to produce vulnerability functions that relate the probabilities of various damage states to loading intensities for different quality classes of blocky rock mass. The results indicated that the fragility curves we obtained could accurately depict the evolution of the inner and outer shell damage around the tunnel. Therefore, we have provided engineers with a tool that can predict levels of damages associated with different failure mechanisms based on variations in rock mass quality and in situ stress state. Our method is a numerically developed, multi-variate approach that can aid engineers in making informed decisions about the robustness of underground tunnels.

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]

Earthquakes and floods in Albania are devastating, but combining these two different hazards in terms of action on bridge structures may lead the bridge to collapse. This article presents a seismic risk assessment of a code-conforming precast reinforced concrete bridge located in a region prone to earthquakes and where local scour induced by floods is a significant concern. The seismic action is considered using a group of ground motion accelerograms generated by matching the accelerogram of the 29 November 2019 earthquake in Durres (M = 6.4), Albania, to the target response spectrum. The scouring effects on the bents of the bridge are characterized by the scour depths. A set of non-linear time-history analyses of the bridge are performed to assess the bridge's performance. The bridge fragility curves are generated and analyzed for multi-hazard scenarios at both element and system levels for different flow discharge values and PGA levels. The result shows a low seismic risk of the bridge with bearings when considering the local scour induced by flood events in the seismic analysis due to their flexibility to adapt to changes in structure geometry and significant foundation stiffness. This research also emphasizes the significance of choosing the right foundation type and depth for bridges located in areas prone to local scour induced by floods. [ABSTRACT FROM AUTHOR]

The development of fragility curves is an important step in seismic risk assessment within the scope of performance‐based earthquake engineering. The goal of this work is to use machine learning methods (regression‐based tools) to forecast the large‐span precast parking structural responses and fragility curves. This study proposes five predicting models based on machine learning to evaluate the seismic performance of the large‐span precast parking structures, including: neural networks, genetic algorithm‐based neural networks, support vector machine, decision tree and random forest. A database that includes 453 numerical synthetic results was used to train and test the machine learning models. The seismic performance of large‐span precast parking structures were predicted using the constructed machine learning models. Finally, the sensitivity analysis of input parameters was conducted. From this paper we can conclude that: (1) the genetic optimization‐based neural networks' predicting model has the most accurate predictive ability for seismic fragility estimation and (2) the structural responses and the fragility curves of parking structures are related to the differences of the stiffness of the connectors and the number of floors, of which the stiffness of the connectors should be given special attention. [ABSTRACT FROM AUTHOR]

Earthquake-induced pounding in bridges is a complex contact phenomenon in which the dynamic responses of structures, including collisions between deck and abutments, are strongly related to structural properties and earthquake excitation. The goal of this study is to develop and compare the seismic fragility curves of overall system and individual components of regular and irregular box-girder highway bridges in two cases: with pounding and without pounding. For this purpose, four levels of altitudinal irregularity, ranging from regular to highly irregular, are considered. To extend the results for all bridges in the same class, different sources of uncertainties related to earthquakes, structural geometries, and material properties are taken into account. The analytical fragility curves have been developed based on nonlinear time history analyses in OpenSees finite element software for the cases with and without pounding effects. The process has been repeated for each two-, three-, and four-span classes at four irregularity levels. The fragility function parameters for the two cases with and without pounding have been compared for all classes considered in this study. Using fragility functions, this paper clarifies the interactive roles of irregularity and pounding between deck and abutments for seismic vulnerability of multi-span box-birder highway bridges. The results indicate that collisions often show an adverse effect on all structural components. It has also been observed that the detrimental effect of pounding on seismic fragility is more apparent in irregular bridges when compared with regular ones. In addition, the study introduces a conversion coefficient to clarify the effects of pounding on the fragility of bridge components and the overall system. This coefficient can be applied in both conventional analytical methods like static or simplified analysis and technical earthquake models like HAZUS, adjusting fragility values for pounding and irregularity effects. [ABSTRACT FROM AUTHOR]

Research on disaster damage estimation for buildings has gained extensive attention due to the increased number of disastrous events, facilitating risk assessment, the effective integration of disaster resilience measures, and policy development. A systematic mapping study has been conducted, focusing on disaster damage estimation studies to identify trends, relationships, and gaps in this large and exponentially growing subject area. A novel approach using machine learning algorithms to screen, categorise, and map the articles was adopted to mitigate the constraints of manual handling. Out of 8608 articles from major scientific databases, the most relevant 2186 were used in the analysis. These articles were classified based on the hazard, geographical location, damage function properties, and building properties. Key observations reveal an emerging trend in publications, with most studies concentrated in developed and severely disaster-affected countries in America, Europe, and Asia. A significant portion (68%) of the relevant articles focus on earthquakes. However, as the key research opportunities, a notable research gap exists in studies focusing on the African and South American continents despite the significant damage caused by disasters there. Additionally, studies on floods, hurricanes, and tsunamis are minimal compared to those on earthquakes. Further trends and relationships in current studies were analysed to convey insights from the literature, identifying research gaps in terms of hazards, geographical locations, and other relevant parameters. These insights aim to effectively guide future research in disaster damage estimation for buildings. [ABSTRACT FROM AUTHOR]

This paper evaluates the effectiveness of a novel capacity-design based retrofit for improving both the local and global behaviour of existing reinforced concrete buildings using fibre-reinforced polymers. The approach was previously tested on beam-column joints and is here extended to the building level. A new fibre-element model for the global retrofit is proposed and validated against full-scale experiments. Non-linear push-over analyses confirm the adequacy of the retrofit and fragility analyses are used to compare it to a simpler local retrofit. Finally, cost-benefit analyses for three levels of seismicity highlight the cost-effectiveness of the global retrofit for moderate to high seismicity. [ABSTRACT FROM AUTHOR]

Unreinforced masonry (URM) buildings in historic urban areas of European countries are generally clustered in an aggregate configuration and are often characterized by façade walls mutually interconnected with adjacent ones. As a result, the seismic performance of buildings in an aggregate configuration can be affected by the mutual interaction between the adjacent units. This interaction, often called the aggregate effect, could significantly influence the level of the seismic vulnerability of URM buildings in aggregate configuration toward in-plane and out-of-plane mechanisms, the latter being the object of the present paper. Traditional methods for assessing the seismic vulnerability of URM buildings neglect the interactions between adjacent buildings, potentially underestimating the actual vulnerability. This study aims to derive fragility curves specific for UMR buildings in aggregate configuration and proposes an innovative methodology that introduces the aggregate effect into an analytical approach, previously developed by the authors for isolated URM buildings. The aggregate effect is modeled by accounting for the friction forces arising among adjacent facades during the development of out-of-plane overturning mechanisms by considering different scenarios, based on how façade walls interact with neighboring structures (e.g., whether they are connected to transverse and/or lateral coplanar ones). The proposed approach is applied to a real case study of an Italian historical center. The obtained results demonstrate that the aggregate effect significantly influences the fragility curves of URM buildings arranged in aggregate configurations. This highlights the importance of considering this effect and the usefulness of the proposed approach for large-scale assessments of seismic vulnerability in historic urban areas, contributing to sustainable disaster risk prevention. [ABSTRACT FROM AUTHOR]

The earthquake sequence that occurred on 6 February 2023 in Turkiye caused significant damage to various infrastructures including geostructures such as dams. A total of 17 earth dams within a 200-km radius of the earthquake epicenter experienced varying degrees of damage, ranging from minor (∼2 cm) to major (up to ∼150 cm) deformations. As study of these reveals that the damaged dams are located within the closest distance to the fault of less than 30 km, with an average value of ∼12 km. This study specifically focuses on the seismic displacement analysis of the 17 damaged dams, utilizing the sliding block methods. The recorded motion data was analyzed using the kriging technique to estimate the spectral response at the dam sites. Moreover, the recorded ground motions were scaled to the resonant period of the dam site to estimate acceleration time history. The findings reveal that the rigid block analysis can provide an average estimation of seismic displacement with a relative error of less than 44%. The results of the damage analysis indicate that seven dams reached the ultimate limit state and two dams experienced the serviceability limit state. Moreover, the univariate and multivariate fragility functions are developed to estimate seismic probabilistic analysis of earth dams based on the observed data and the limit states. The results show that the selection of a single intensity measure (IM) and a combination of IMs can affect the predicted probability of failure. The findings provide an insight into the resilience assessment of dams and other geosystems during this strong earthquake. [ABSTRACT FROM AUTHOR]

Our study introduces a methodology to improve large-scale seismic damage assessment by incorporating site-specific fragility curves, considering soil–structure interaction (SSI) and site amplification (SAmp) effects. The proposed method proposes an enhanced building exposure model, using publicly available data and the open-source OpenQuake Engine software. The objective is to determine whether a more refined approach incorporating SSI and SAmp can impact the final damage calculation. We evaluate our approach by estimating the damage distribution for the Thessaloniki 1978 earthquake scenario using the actual building stock of Thessaloniki. We present several maps with aggregated damages at different levels to investigate the spatial variability of SSI and SAmp, and their influence on the resulting damages. Our estimated physical damages have been compared with those obtained using approaches from the existing literature. Apparently, using an updated building exposure model to assess damages makes any comparison with past observed damages challenging. Nevertheless, incorporating SSI and SAmp in large-scale damage assessment can provide valuable support for strategic decision-making in cities and improve the accuracy of the expected loss assessment due to a seismic event. [ABSTRACT FROM AUTHOR]

The role of critical infrastructures in maintaining the functioning of the economy and society and ensuring national security, particularly their durability in delivering essential services during crises, including natural disasters such as earthquakes, is critical. This work introduces an analytical methodology to quantify potential earthquake damage to power stations and evaluate the cost-effectiveness of measures to enhance their seismic resistance. By employing fragility curves and probabilistic risk analyses, this approach provides a structured framework for the comprehensive assessment of risks and the identification of economically practical mitigation strategies. A detailed examination of strategies to protect critical power station components against seismic activity is presented, revealing that a minor investment relative to the overall project budget for earthquake-proofing measures is economically effective. This investment, representing a marginal fraction of 0.5% of the total project expenditure significantly reduces the seismic risk of power station failure by 36%. Reinforcing essential elements, including switching stations, water treatment facilities, and water tanks, is emphasized to ensure their continued operation during and after an earthquake. This research highlights the critical significance of integrating risk assessment with benefit-to-cost analysis in strategic decision-making processes, supporting the prioritization of investments in infrastructure enhancements. These enhancements promise substantial reductions of risks at minimal costs, thus protecting essential services against the impacts of natural disasters. This research contributes to state-of-the-art research in critical infrastructures resilience. [ABSTRACT FROM AUTHOR]

AbstractThe 5 August 2014 Orkney earthquake in South Africa caused significant damage to low-cost unreinforced masonry buildings. After the earthquake, post-earthquake surveys were conducted to assess damage and deduce the intensity experienced by these buildings. During these surveys, only buildings that were reported as damaged were investigated. This study conducted an empirical seismic vulnerability assessment using data collected from those surveys. However, for a comprehensive assessment, the data should include all buildings in the study area. Hence in this study, a first-order approximation was applied to gather sufficient data to construct fragility curves for low-cost unreinforced masonry buildings in South Africa. The damage probability matrix technique was used for fragility curve construction. The fragility curves were constructed using the intensity and damage data, statistical models, and model fitting techniques. The fragility curves obtained in this study predicted comparable but slightly lower damage compared to other curves for unreinforced masonry buildings of similar typology. Although the method applied was able to produce fragility curves comparable with other studies, it is recommended that in order to get a reliable fragility curves all the buildings in the study area should be investigated including those that suffered little to no damage.

The fragility curve expresses the probability that an asset exceeds some serviceability state for a given level of environmental perturbation or other loadings. It is an important component in the quantitative risk analysis and resilience evaluation of infrastructure exposed to natural hazards. Incidences of over-settlement of embankments are increasingly reported due to more intense and longer-duration rainfall events. This paper develops fragility curves for the rainfall-induced embankment settlement. For this purpose, an embankment incorporating enhanced seepage and displacement analysis within unsaturated soil conditions is modelled based on a reported case history. A Monte Carlo simulation is used for rainfall infiltration and embankment deformation analysis under various rainfall scenarios. Probability values are obtained to achieve three levels of damage states in terms of road embankment settlement. The parametric analysis produces the exceedance probability curves for various rainfall intensities, saturated permeabilities and embankment slope angles. This work offers an efficient tool for assessing fragility to rainfall-induced excessive settlement of embankments. [ABSTRACT FROM AUTHOR]

This study provides a discussion using a database of historic masonry bell towers struck by past Italian earthquakes, which is the result of an extensive literature review on post-earthquake reconnaissance reports and scientific publications. The observed damage is analysed to give an insight into the seismic behaviour and vulnerability of this peculiar building typology. To this end, a macro-scale approach is adopted, two distinct damage mechanisms are identified and evaluated, and a damage index for each tower is computed. This enables to develop the damage probability matrices, providing the frequency of damage occurrence. Moreover, vulnerability and fragility curves are derived to help the prediction of future possible damage scenarios. The developed vulnerability and fragility curves are compared with the mean damage observed in the samples included in the database. This comparison allowed to check the robustness of rapid procedures today available in the field of seismic risk assessment for the specific case of historic masonry towers. [ABSTRACT FROM AUTHOR]

Existing Reinforced Concrete School buildings with low earthquake resistance may suffer structural failure or severe damage in a catastrophic seismic event. Ascertaining earthquake resistance in existing school buildings is vital to confirming the safety of students, teachers, and all school members. Reinforced concrete (RC) has been used significantly for numerous years as the primary material due to its easy access and low cost-effectiveness in construction. The current research focused on analyzing the existing RC school buildings designed and constructed in various regions of Afghanistan over the last three decades. Seismic fragility curves, which are generated from incremental dynamic analysis (IDA), have been used to evaluate the damage probability of RC school buildings against earthquake ground motions. In this investigation, 34 RC school buildings were selected from an extensive database and subsequently classified as either A-type or B-type based on specific criteria, including design details and construction year. Following this classification, an assessment of the seismic damage probability for these buildings was conducted using probabilistic models based on IDA curves. The results indicate that A-type school buildings with newer construction are less prone to damage compared to B-type school buildings, showing improved resilience. Especially the B-type buildings in seismic Zone-I are found to be highly vulnerable under the maximum considered earthquake scenarios. [ABSTRACT FROM AUTHOR]

Vertical geometric irregular reinforced concrete (RC) buildings are widely used in structural engineering due to their aesthetic appearance and functional characteristics. Indeed, improving their reliability and seismic performance is of crucial interest and has even become a necessity. This research study underlines the importance of using shear walls (SW) as a fundamental means of reinforcement for this type of structure. Twenty models, including ten with SW and ten without SW, of mid-rise buildings with setback irregularity were considered for this purpose, and fragility analyses were carried out, using a non-linear procedure, to highlight the potential usefulness of shear walls for irregular structures. The results of this work clearly indicate that the dynamic behavior and response of buildings have been improved by the use of shear walls. The fragility study reveals that for some cases the damage probability is reduced, with the difference exceeding 13% for the majority of models, and for some cases the differences are highly significant, ranging from 30% to 60%. This shows the benefits of incorporating shear walls into the design phase of irregular buildings. [ABSTRACT FROM AUTHOR]

The complex interactions between the weather, the environment, and electrical infrastructure that result in power outages are not fully understood, but because of the threat of climate change, the need for models that describe how these factors produce power grid failures is acute. Without them, it remains difficult to understand the amount of weather-related damage we may expect in the future, as well as how changes or upgrades to the infrastructure may mitigate it. To address this problem, a modeling framework is proposed in this article that integrates data derived from structural vulnerability analysis into a machine-learning based weather-related power outage prediction model to create a model that is sensitive both to the weather and the technical configuration of the infrastructure. This Physics Informed Machine Learning (PIML) approach is demonstrated using data from a major power utility operating in the US State of Connecticut, and is compared against a fragility curve modeling approach using some of the same data. The validation of the PIML model shows superior predictive ability, as well as variable sensitivities that follow expected patterns. These results suggest that the model would be able to evaluate the influence that different configurations of the infrastructure would have on the occurrence of power outages caused by severe storms, allowing for the anticipated effects of investments in infrastructural upgrades to be quantified and optimized.

This study presents a novel framework for integrating corrosion effects into critical infrastructure seismic risk assessment, focusing on reinforced concrete (RC) structures. Unlike traditional seismic fragility curves, which often overlook time-dependent degradation such as corrosion, this methodology introduces an approach incorporating corrosion-induced degradation into seismic fragility curves. This framework combines time-dependent corrosion simulation with numerical modeling, using the finite–discrete element method (FDEM) to assess the reduction in structural capacity. These results are used to adjust the seismic fragility curves, capturing the increased vulnerability due to corrosion. A key novelty of this work is the development of a comprehensive risk assessment that merges the corrosion-adjusted fragility curves with seismic hazard data to estimate long-term seismic risk, introducing a cumulative risk ratio to quantify the total risk over the structure’s lifecycle. This framework is demonstrated through a case study of a one-story RC moment frame building, evaluating its seismic risk under various corrosion scenarios and locations. The simulation results showed a good fit, with a 3% to 14% difference between the case study and simulations up to 75 years. This fitness highlights the model’s accuracy in predicting structural degradation due to corrosion. Furthermore, the findings reveal a significant increase in seismic risk, particularly in moderate and intensive corrosion environments, by 59% and 100%, respectively. These insights emphasize the critical importance of incorporating corrosion effects into seismic risk assessments, offering a more accurate and effective strategy to enhance infrastructure resilience throughout its lifecycle.