Vulnerability Of Buildings Research Articles

Machine learning (ML) algorithms for seismic vulnerability assessment of school buildings in high-intensity seismic zones

Ensuring seismic resilience of school buildings is crucial for safeguarding their occupants during earthquakes. This paper focuses on assessing the seismic vulnerability of school buildings constructed in the Kashmir region of Pakistan after the 2005 earthquake, which claimed the lives of 19,000 school-going children. It explores the feasibility of utilizing machine learning (ML) algorithms for enhanced rapid screening of schools to establish fragility information. The study is based on data collected in the Kashmir region and focuses on assessing representative reinforced concrete (RC) and unreinforced masonry (URM) school buildings. To determine structural fragility curves, Incremental Dynamic Analyses (IDA) are performed, simulating fifteen historical earthquakes. Four different ML models are investigated to predict fragility curves, including Random Forest (RF), Artificial Neural Networks (ANNs), Extreme Gradient Boosting (XGBoost), and Extremely Randomized Tree Regressor (ERTR). The performance of the algorithms is compared using performance metrics such as precision, accuracy, and f1 score. The study identified XGBoost and RF as the highest performing algorithms, achieving highly satisfactory accuracy with the correlation coefficients of 0.91 and 0.81 for RC schools, and 0.88 and 0.83 for URM schools during testing phases. Alternatively, ERTR’s performance could not justify its use for structural seismic vulnerability assessments. This highlights the significant potential of using ML algorithms for automated seismic vulnerability evaluation of buildings, greatly reducing the overall computational burden while maintaining high accuracy and reliability.

Wide area maps of building differential deformations

Abstract. The European Ground Motion Service (EGMS) uses Sentinel-1 data to monitor and measure land displacement across Europe, delivering information on ground motion phenomena. The EGMS service includes three types of products, enabling the analysis of annually updated ground motion data. The authors are working on a project aimed at computing the spatial gradient of land deformation and generating wide-area differential deformation maps. This type of maps can help identifying potentially vulnerable buildings and urban structures. The project involves developing a software pipeline to compute and convert original deformation data and creating a customized web viewer to display the results. Given the large volume of the processed datasets, with several millions of measurement points an accurate algorithm implementation is needed. The resulting information will aid in monitoring anthropogenic phenomena and their impact on building and infrastructures. This will be essential for urban management and risk mitigation planning.

Multi-attribute-based procedure for seismic loss scenario in a historical area

AbstractSeismic events have shown to be exceedingly damaging to structures over time, with serious social and economic consequences. As a result, large-scale seismic risk assessments are essential for reducing the potential damage from future earthquakes. Therefore, the proposed study attempts to examine the vulnerability and risk of unreinforced masonry buildings (URM) placed in aggregate conditions in a historical area of the city centre of Lisbon. To this purpose, a comprehensive exposure model was developed combining satellite remote sensing, GIS software, and census data. Subsequently, seismic hazard was evaluated in the area, considering both Peak Ground Acceleration (PGA) and macro-seismic intensity for different return periods (i.e. 2-50-100-475-975-2500-5000 years). Vulnerability was assessed by introducing a novel approach to earthquake risk assessment using Multi-Criteria Decision-Making methodologies. Specifically, the method employs the Analytic Hierarchy Process (AHP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) computational methods to evaluate parameter weights and vulnerability index. Damage scenarios, fragility curves and mean damage ratios curves were provided to offer an overview of the vulnerability of the assets exposed to risk. Finally, the expected consequences were evaluated in terms of direct economic losses showing an economic loss of 595 M€ for a 475-years return period, while 1108 M€ for 5000-years. This study significantly enhances seismic analysis for urban areas by introducing a Multi-Criteria Approach. This method simplifies vulnerability assessment, ensuring ease of application and reproducibility. Its insights offer valuable support for disaster risk management decisions, facilitating the implementation of resilience and risk-reduction strategies.

Seismic Vulnerability Assessment of Historic Centers with Two Fast Methods Based on CARTIS Survey Methodology and Fragility Curves

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.

Seismic vulnerability analysis of hospitals and school buildings considering the Gaussian regression algorithm

This study combines the Gaussian regression algorithm to propose a nonlinear regression model that can be used to evaluate the seismic vulnerability of regional hospitals and school buildings. The failure features and disaster mechanisms of hospital and school buildings affected by the Jishishan (JSS) earthquake on December 18, 2023, and the Wenchuan (WC) earthquake on May 12, 2008, were reported. The samples of 252 damaged buildings (37 hospitals and 215 schools) in Dujiangyan city affected by the Wenchuan earthquake for which the author participated in the survey were collected and counted. Hospitals and school buildings were classified according to the types of reinforced concrete (RC) and masonry structures, and earthquake vulnerability probability matrices for hospital and school building clusters were established considering the actual failure probabilities. A total of 2103,213 acceleration records (from the Wenchuan earthquake) monitored by 12 real stations were selected. Using dynamic time history and response spectrum analysis methods, time history and spectrum curves were generated, considering the influence of different seismic directions. Using the developed Gaussian regression model, vulnerability comparison curves and parameter matrices considering multiple regression algorithms were generated. This paper considers the effects of the construction year and number of floors on the seismic vulnerability of hospital and school buildings. Seismic vulnerability curves and failure probability matrices were generated and established on the basis of actual structural failure probabilities. According to regression and vulnerability surface analysis, the evaluation results of the proposed model are highly consistent with actual field observations.

Identification of risk factors that are dominant to the vulnerability of buildings due to earthquakes and their mitigation by the importance index method

Identification of risk factors that are dominant to the vulnerability of buildings due to earthquakes and their mitigation by the importance index method

Urban Vulnerability Assessment of Sea Level Rise in Singapore through the World Avatar

This paper explores the application of The World Avatar (TWA) dynamic knowledge graph to connect isolated data and assess the impact of rising sea levels in Singapore. Current sea level rise vulnerability assessment tools are often regional, narrow in scope (e.g., economic or cultural aspects only), and are inadequate in representing complex non-geospatial data consistently. We apply TWA to conduct a multi-perspective impact assessment of sea level rise in Singapore, evaluating vulnerable buildings, road networks, land plots, cultural sites, and populations. We introduce OntoSeaLevel, an ontology to describe sea level rise scenarios, and its impact on broader elements defined in other ontologies such as buildings (OntoBuiltEnv ontology), road networks (OpenStreetMap ontology), and land plots (Ontoplot and Ontozoning ontology). We deploy computational agents to synthesise data from government, industry, and other publicly accessible sources, enriching buildings with metadata such as property usage, estimated construction cost, number of floors, and gross floor area. An agent is applied to identify and instantiate the impacted sites using OntoSeaLevel. These sites include vulnerable buildings, land plots, cultural sites, and populations at risk. We showcase these sea level rise vulnerable elements in a unified visualisation, demonstrating TWA’s potential as a planning tool against sea level rise through vulnerability assessment, resource allocation, and integrated spatial planning.

Comparison of seismic assessment guidelines using a case study reinforced concrete wall building

There are several seismic assessment standards and guidelines available around the world that can be used to identify vulnerable buildings. The assessment procedures and criteria in these documents are different, and thus, the assessment outcomes for a particular building, if assessed using different standards, can also be different. In this study, provisions of the linear static and non-linear static analysis procedures of three prominent seismic assessment documents, the American Society of Civil Engineers /Structural Engineers Institute standard ASCE 41 (2017) [1], the New Zealand Seismic Assessment Guidelines (2017) [2], and the European Standard EN 1998-3 (2005) [3] (also known as Eurocode 8 Part-3 or EC8-3) are discussed and compared, highlighting some of their similarities and differences. A reinforced concrete (RC) wall building used in FEMA P-2006 (2018) [4] for demonstration of ASCE 41 provisions is taken as the case study building for comparison of the assessment provisions. The linear and non-linear static analysis procedures specified in the three documents are applied to the case study building and the assessment outcomes are compared. The assessment results are found to vary across the analysis methods and guidelines. However, the critical governing vulnerability for the building is found to be the same. It is observed that with the simplifying modelling assumptions, coupled with the inherent conservatism in the assessment using linear static analysis, a more conservative outcome is obtained using the linear static methods as compared to the non-linear static methods. Overall, EC8-3 provisions are found to be the most conservative of all three guidelines considered for the assessment of the example building.

The role of passive, active, and operational parameters in the relationship between urban heat island effect (UHI) and building energy consumption

The energy performance of buildings located in urban areas is strongly influenced by the UHI phenomenon, which usually leads to higher cooling energy consumption and lower heating energy consumption. Despite the known effects of UHI on building energy consumption, there is a lack of detailed knowledge on the role of building design and operational parameters in determining the effects of UHI on building energy use. To address this knowledge gap, this study analyzes the impacts of UHI on annual, heating, and cooling energy consumption of 16 prototype buildings located in 16 climate zones in the United States. The objective is to determine the relative relevance of building types (e.g., residential, commercial, healthcare facilities etc.), occupancy parameters (e.g., occupancy schedule) and the Heating, Ventilation and Air Conditioning (HVAC) systems in governing the impact of UHI on the building energy use matrices. Additionally, the thermal properties of the building envelope were evaluated to determine their relative importance in mitigating the effects of UHI on building energy performance. We found that, among the studies building types, while the cooling energy use of restaurant and outpatient healthcare buildings was most affected by UHI (higher cooling energy demands), the outpatient healthcare buildings were most impacted by UHI in terms of their heating energy use (lower heating energy use). The selection of HVAC systems type was found to have negligible influence on the energy impacts of UHI. Lastly, with regard to the thermal properties of the building envelope, window insulation was noted to be the most influential thermal property, followed by roof and wall insulation. Also, the role of insulation as well as other thermal properties was higher in the context of UHI’s impact on heating energy consumption as compared to cooling energy consumption. Not only are the results of this study useful for urban planning purposes to determine the vulnerability of different buildings to UHI, but they also are beneficial to UHI-resilient building designs.

Balance point concentration: An indicator for classroom performance against outdoor PM2.5

Indoor air quality significantly affects occupants' health, making it crucial to evaluate a building's vulnerability to air pollution. In this study, 17 classrooms in urban areas of Seoul, Korea were monitored to determine how long a clean air environment can be maintained. We propose the balance point concentration (BPC) as the threshold value of outdoor PM2.5 concentration that can maintain PM2.5 in classrooms at the target value of 15 μg/m3. Based on the mass-balance equation, BPC is a comprehensive indicator that considers PM2.5 that can penetrate through building envelope, be generated from indoor activities, and be removed by an air purification system. For non-occupied classrooms, the BPC ranged from 20.6 to 34.3 μg/m3. We find that better airtightness reduced air pollution in buildings. However, due to students' activities, BPC decreased to 7.6–12.0 μg/m3. Lastly, in classrooms with mechanical ventilation systems in operation, the BPC ranged from 24.3 to 34.2 μg/m3, showing improved performance. Under such conditions, students can spend more than 88 % of the year in a classroom environment with clean air. In areas with low outdoor pollution levels, satisfaction can be even higher. Evaluating buildings performance using BPC allows for a more intuitive and clear assessment compared to existing indicators. When outdoor concentrations exceed BPC, additional air quality management in the classroom is necessary. This can be widely utilized when planning improvements to the environment or the operation of air purification system.

Integration of Building Age into Flood Hazard Mapping: A Case Study of Al Ain City, United Arab Emirates

Accurate and timely information on building age is essential for mitigating the impacts of natural disasters such as earthquakes and floods. Traditional methods for collecting these data are often inefficient and costly. This study leverages remote sensing and machine learning to classify building age and integrate this information into a comprehensive flood hazard map for Al Ain City. By combining building age with elevation, topography, land use, population density, and other factors, we generated a flood hazard map that effectively identifies high-risk areas. Our results show that a significant portion of the city is has low potential for flooding (61%), while others face moderate (32%), high, or very high flood hazards. This study provides crucial information for informed decision-making regarding future urban planning, disaster management, and development strategies in Al Ain City. By identifying vulnerable buildings in advance, it supports efforts to reduce disaster risks, protect lives, and optimize resource allocation.

Natural Lime–Cork Mortar for the Seismic and Energetic Retrofit of Infill Walls: Design, Materials, and Method

Recent seismic events have prompted research into innovative and sustainable materials for strengthening and repairing obsolete and vulnerable buildings. These earthquakes have exposed the high seismic vulnerability of existing reinforced concrete (RC) buildings, particularly in secondary structural elements like infill walls. In addition to structural issues, these buildings often face significant energy deficiencies, such as thermal bridges, due to inadequate insulation. Traditionally, structural and energy improvements for residential buildings are addressed separately with different methods and protocols. This preliminary study is part of a broader research initiative at the University of Reggio Calabria (Italy), aiming to design an innovative fiber-reinforced plaster using natural, sustainable, and locally produced materials to enhance the energy and structural performance of existing wall infills. The study investigates two plaster matrices made of natural hydraulic lime and silica sand, with 15% and 30% cork granules added. Mechanical and thermophysical tests on multiple specimens were conducted to evaluate their suitability for seismic and energy retrofitting of infill walls. Results indicate that adding cork reduces mechanical strength by approximately 42% at a 30% cork content without compromising its use in seismic retrofitting. Thermophysical tests show improved thermal performance with a higher cork content. These findings suggest that the lime–cork mixture at 30% is effective, offering excellent ductility and serving as a promising alternative to traditional cementitious plaster systems. The next experimental phase will test matrices with varying percentages of gorse fiber.

Estimating spatio-temporal variable parameters of Epidemic Type Aftershock Sequence model in a region with limited seismic network coverage: a case study of the East African Rift System

SUMMARY The Epidemic-Type Aftershock Sequence (ETAS) model is currently the most powerful statistical seismicity model that reproduces the general characteristics of earthquake clustering in space and time. However, its application can be hampered by biased parameter estimations related to earthquake catalogue deficiencies, particularly in regions where the spatial coverage of local recording networks is relatively poor. Here, we systematically investigate the possible influences of the effect introduced by data truncation through the choice of the cut-off magnitude (${{m}_{\rm cut}})$ and missing events due to heterogeneity of the seismic network on ETAS parameter estimates along the East African Rift System (EARS). After dividing the region into six source zones based on rheological and mechanical behaviours, the ETAS model is fitted to the earthquakes within each zone using the Davidon–Fletcher–Powell optimization algorithm. The fits and variations in parameter estimates are compared for each zone to the others and the seismological implications are discussed. We found that some parameters vary as a function of ${{m}_{\rm cut}}$ primarily driven by changes in catalogue size. Additionally, a systematic regional dependency of ETAS parameters is found across source zones. Furthermore, a median heat flow value for each analysed source zone in the EARS is calculated. In contrast to previous findings in other tectonic settings, the results reveal no significant correlations between the crustal heat flows and the ETAS parameters describing earthquake productivity (${{K}_0}$) and the relative efficiency of an earthquake with magnitude M to produce aftershocks ($\alpha $). Our findings have significant implications for understanding the mechanisms of earthquake interaction and, therefore, provide tight constraints on the model's parameters that may serve as a testbed for existing earthquake forecasting models in this region where the vulnerability of local buildings and structures exacerbate seismic risk.

Doing nothing is no solution: Coastal erosion management in Guardamar del Segura (Spain)

Human activities like dam construction in rivers and urban development in coastal areas, combined with climate change, are degrading coastal systems. As a result, many European countries have implemented laws and strategies to protect their shorelines. This research focuses on Guardamar del Segura in Spain, where human actions in the Segura River basin and changes in wave patterns have significantly damaged the beach-dune system, with erosion rates reaching −0.71 m/year. If these rates and extreme climate events continue to rise, the shoreline will keep retreating, leading to the destruction of beachfront houses and parts of the dune surface by 2050. This will cause changes in land ownership and irreversible ecological damage to the natural ecosystem. The Spanish Public Administration's inaction on coastal protection is due to a lack of coordination between government levels, insufficient technical tools to combat erosion, and inadequate legal mechanisms to fund protective measures. In contrast, countries like Germany, the Netherlands, and the United Kingdom have effective models in place. Potential solutions for Guardamar del Segura include beach and dune restoration or adding sand through revetments. Another option is a managed retreat of the most vulnerable buildings to avoid continuous repair and maintenance costs. Coastal erosion is a growing issue, and preserving our coastal ecosystems requires proactive measures, so doing nothing is no solution.

Empirical seismic fragility of masonry buildings in historical centres accounting for structural interventions

Fragility models are widely employed to forecast seismic damage in built environments. However, the actual conditions of buildings, depending on their construction systems and transformations, are crucial for model reliability, especially in historical centres.In this paper, an empirical fragility model for residential masonry buildings from data collected within 19 historical centres struck by the 2016 Central Italy earthquake is proposed. The dataset includes both traditional unreinforced and hybrid buildings, where reinforced concrete elements were applied in the 1980s according to seismic reinforcement prescriptions for existing structures.This study acknowledges the impact of such structural modifications on the seismic performance of buildings, which can alter their vulnerability classification either improving or worsening it. The intensity measure for the fragility functions is the peak ground acceleration obtained from actual records through interpolation for each centre. Damage data and vulnerability assessment of 2134 traditional and hybrid structural units are conducted in the framework of the European Macroseismic Scale (EMS-98). The fragility functions are plotted for both structural types and EMS-98 vulnerability classes, also considering the contribution of structural interventions, and then compared to literature empirical models. Hybrid buildings achieve a behaviour similar to traditional buildings when floors are strengthened but walls are not. However, when both masonry walls and floors are strengthened, their performance significantly improved, approaching that of modern clay block buildings with rigid floors. Compared to literature models, the proposed one showed good compatibility for the most vulnerable buildings, whereas less vulnerable ones appeared even stronger thanks to interventions.

Building risk assessment methodology for explosive and non-conventional terrorist attacks

An original methodology suitable for the assessment of the risk of a terrorist attack in a given site/building is proposed and illustrated for the case of an explosive or non-conventional (Chemical, Biological, Radiological, Nuclear and explosive—CBRNe) attack. The Building Risk Assessment Methodology discussed in this paper represents the arrival point of a detailed analysis and research carried out during the past 5 years and provides the synthesis of different results obtained for the assessment of Building Threats and Building Vulnerabilities. These two assessments were discussed in detail in other already published papers. The effort presented in this work is to deploy a risk and impact assessment technique for buildings that can be adopted in any operating scenario in the presence of explosive or non-conventional threats. The main target of the methodology is to provide a sufficiently accurate estimate of the risk in a simple fashion. The methodology allows to manage the different kinds of risk related to the explosive and non-conventional threats, and it is useful for identifying a ranking of risks for different buildings in different portions of territory and for prioritizing actions and investments in preparedness, protection and resilience of critical areas and critical infrastructures. In the paper, the results of two different case studies for three different threats will be considered, analyzed and compared.

Seismic Risk Assessment in School Buildings: A Comparative Study of Two Assessment Methods

Seismic risk assessment in school buildings is critical for ensuring the safety and resilience of educational institutions against seismic events. This paper presents a new seismic risk methodology named MM Risk and comparative study with Adriseismic methodology used for seismic risk assessment. The study aims to provide insights into the effectiveness and reliability of these methods in evaluating the seismic vulnerability of school buildings. Through a comprehensive review of the existing literature and application on a dataset of 213 schools (367 buildings), this paper evaluates the strengths and limitations of each method in terms of accuracy, complexity, and practical applicability. The results show that by integrating the approach of Adriseismic methodology and incorporating extensions related to irregularities, the social risk component (number of users), and the ability to assess different types of structures, a comprehensive and tailored methodology for assessing seismic risk can be developed. This is important since these factors are strongly influencing the seismic risk of schools as connected systems. Furthermore, this paper explores the implications of these findings for improving seismic risk mitigation strategies in school buildings. MM Risk methodology places over 70% of school buildings in the medium seismic risk category and 27% in the high seismic risk category. On the other hand, the Adriseismic methodology is more stringent, classifying 60% of school buildings into high and very-high risk categories. This disparity undoubtedly influences the prioritization list for seismic risk mitigation measures. However, definitely the comparative analysis presented in this paper offers valuable guidance for engineers, policymakers, and stakeholders involved in the seismic retrofitting and design of school buildings, ultimately contributing to the enhancement of seismic resilience in educational infrastructure.

Seismic Scenario Losses Estimation Based on the Vulnerability of Pre-Code Masonry Buildings in the Metropolitan Area of Lisbon

ABSTRACT 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.

Investigating the seismic vulnerability of traditional ancient Tibetan buildings via structural subscaling experiments

Investigating the seismic vulnerability of traditional ancient Tibetan buildings via structural subscaling experiments

Multi-hazard direct economic loss risk assessment on the Tibet Plateau

Natural disasters are becoming increasingly regional, frequent, and complex. Semi-quantitative risk assessments based on risk indices or relative risk levels lack quantitative parameters to characterize losses adequately. This study focuses on earthquakes and geological disasters, quantitatively assessing the risk of probable maximum loss (PML) from multi-hazard on the Tibet Plateau (TP) in terms of both absolute and relative values. The results indicate that total PML from multi-hazard on the TP is estimated at 465.5 billion CNY, with a relative value of 5.3%. The total loss value of towns with very high absolute PML is estimated at 254.8 billion CNY, while the relative loss value of towns with very high relative PML is 25.1%. Towns with high absolute value of PML for multi-hazard may have higher fixed asset values, while those with high relative value imply higher vulnerability. Adjusting building structures and reducing the vulnerability of buildings could effectively mitigate the risk of disaster losses caused by multiple hazards.