Vulnerability Assessment Of Buildings Research Articles

First-order approximation towards empirical seismic vulnerability assessment of low-cost unreinforced masonry buildings in South Africa

The 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.

Identification of Surface Deformation-Sensitive Features under Extreme Rainfall Conditions in Zhengzhou City Based on Multi-Source Remote Sensing Data

Extreme precipitation is one of the most prevalent meteorological disasters occurring today. Its occurrence not only causes significant social and economic losses but also indirectly affects surface deformation, creating safety hazards for diverse ground features. Although there are presently high-precision, comprehensive tools such as continuous scattering interferometry to observe surface deformation, it takes a long time to locate potentially vulnerable objects. A monitoring scheme for surface deformation anomalies was devised to address the timeliness issue of identifying sensitive surface features under extreme rainfall conditions. An SAR image of Sentinel-1A is used to derive the surface deformation in three years before and after a rainstorm in the main urban area of Zhengzhou, and the anomaly surface deformation objects after extreme precipitation are screened to determine the surface deformation-sensitive objects. The results indicate that, in the past three years, a 22.14 km2 area in Zhengzhou City has experienced a settlement speed greater than 10 mm/yr. Under the influence of the “7–20” rainstorm in the main urban area of Zhengzhou City, among them, the area of highly sensitive agricultural land for deformation is 2,581,215 m2, and there are 955 highly sensitive houses for deformation, with an excellent recognition effect. This method is effective in rapidly locating surface deformation-sensitive or potentially damaged features; it can provide a reference for the vulnerability and risk assessment of buildings.

Improvement and updating of the SP-BELA method for the vulnerability assessment of masonry and RC buildings

Italy is a country with medium to high seismicity, densely populated and with an architectural heritage highly vulnerable but also very important from a cultural point of view. This fragility was manifested in the recent earthquakes that hit the peninsula. The evaluation of the structures vulnerability is therefore of fundamental importance to plan the seismic risk mitigation interventions that the Government is putting in place. Several research groups are dealing with this issue, including Eucentre (European Centre for Training and Research in Earthquake Engineering), a centre of excellence of the Italian Civil Protection Department (ICPD). Already in 2008 Eucentre researchers had developed SP-BELA, a simplified analytical method for masonry and RC buildings vulnerability assessment at large-scale. Over the years, this method has been improved to represent the behaviour of the structures in an increasingly realistic manner. This has been possible mostly due to the large amount of observed damage data made available by the ICPD. These data, collected in the online platform Da.D.O. (Database of Observed Damage) owned by the ICPD and developed by Eucentre, allowed calibrating the mechanical vulnerability models on the real damages. This paper describes the new calibration of SP-BELA, which also accounts for the effect of infill panels on the building vulnerability, and provides the parameters describing fragility curves obtained from capacity curves that represent the behaviour of typical Italian building taxonomies. Finally, the human and economic losses risk maps, resulting from the application of the method, are also shown and compared with the published maps.

Seismic vulnerability assessment of step-back hill buildings through experimental investigation, numerical simulation and fragility estimation

Seismic vulnerability assessment of step-back hill buildings through experimental investigation, numerical simulation and fragility estimation

Socioeconomic vulnerability assessment of coastal villages and buildings along Andhra Pradesh East Coast of India

Socioeconomic vulnerability assessment of coastal villages and buildings along Andhra Pradesh East Coast of India

Assessment of Seismic Vulnerability of School Buildings: A case study in Bandung, West Java, Indonesia

Indonesia is an earthquake-prone country. In many earthquakes, school buildings suffer the most damage than other public facilities. In 2020, the conditions of around 70% of 218,234 school classrooms in Indonesia were deteriorating. This contributed to a significant earthquake vulnerability. Limited funding for rehabilitation and renovation became an obstacle to reduce the vulnerability. This study proposed that Rapid Visual Screening (RVS), which is a simple method and has a wide coverage, could be a solution to prioritize building rehabilitation. Bandung, the capital city of the most populated province in Indonesia, has complex earthquake hazard risks, which made it a suitable study area for implementing RVS. This study conducted a seismic vulnerability assessment of school buildings in the city of Bandung, Indonesia. The methodology used is based on Indonesia National Disaster Management Agency (BNPB)’s Regulation No. 4 of 2012 on Rapid Visual Screening (RVS) procedure compared to FEMA 154 RVS procedure with local hazard data and building data. RVS was conducted in total 334 elementary school buildings in 30 districts. The result of the BNPB’s RVS procedure showed an average RVS score (S) of 4.455 where 36.53% buildings were in safe condition and 63.47% buildings required further assessment of the conditions from construction experts. The result of the FEMA 154 RVS procedure showed an average RVS score (S) of 0.905 where 22.16% of the buildings were in high probability of grade 4 damage and 77.84% of the buildings were in high probability of grade 3 damage.

A mechanical-based seismic vulnerability assessment method with an application to masonry structures in Cosenza (Italy)

AbstractThe paper presents a mechanical-based framework for the evaluation of local-scale seismic fragility curves. The approach is oriented to a seismic vulnerability assessment of unreinforced masonry buildings and makes use of basic exposure data easily obtained from survey or available in existing database. An efficient finite element model and static nonlinear analyses are employed to assess the structural behaviour. The mechanical-based fragility curves are evaluated using Monte Carlo simulations that allow to account for the uncertainties propagation. The proposed approach is tested on a case-study regarding the city centre of Cosenza, in southern Italy, using exposure information available from CARTIS database.

Assessment of Building Physical Vulnerability in Earthquake-Debris Flow Disaster Chain

Large earthquakes not only directly damage buildings but also trigger debris flows, which cause secondary damage to buildings, forming a more destructive earthquake-debris flow disaster chain. A quantitative assessment of building vulnerability is essential for damage assessment after a disaster and for pre-disaster prevention. Using mechanical analysis based on pushover, a physical vulnerability assessment model of buildings in the earthquake-debris flow disaster chain is proposed to assess the vulnerability of buildings in Beichuan County, China. Based on the specific sequence of events in the earthquake-debris flow disaster chain, the seismic vulnerability of buildings is 79%, the flow impact and burial vulnerabilities of damaged buildings to debris flow are 92% and 28% respectively, and the holistic vulnerability of buildings under the disaster chain is 57%. By comparing different vulnerability assessment methods, we observed that the physical vulnerability of buildings under the disaster chain process is not equal to the statistical summation of the vulnerabilities to independent hazards, which implies that the structural properties and vulnerability of buildings have changed during the disaster chain process. Our results provide an integrated explanation of building vulnerability, which is essential for understanding building vulnerability in earthquake-debris flow disaster chain and building vulnerability under other disaster chains.

Seismic vulnerability assessment of Portuguese masonry buildings

According to the 2011 National Housing Census, masonry buildings comprise more than 50% of the Portuguese building stock. This type of construction has demonstrated a poor performance during the destructive events that struck Portugal in the last century (e.g., 1909 M6.3 Benavente, 1969 M7.8 Algarve, 1980 M6.9 Azores). While some efforts have been made towards the vulnerability assessment of individual masonry buildings or the residential building stock at the national scale, this building class has been the target of limited research. In this study, a comprehensive database of material and geometric properties of granite and limestone buildings was used to generate complex 3D numerical models. These models were subjected to nonlinear time history analysis to derive fragility curves considering the record-to-record and building-to-building variability. The structural damage was defined using two novel engineering demand parameters, and the resulting fragility functions were compared against other existing models. These results can be used directly to generate earthquake scenarios at the country scale or in probabilistic seismic risk analysis to identify regions where risk reduction measures should be prioritized.

Evaluation of rapid visual screening assessment of existing buildings using nonlinear numerical analysis

Different methodologies are available in the literature to perform seismic assessment of existing buildings. Amongst the simplified ones, Rapid Visual Screening (RVS) methodologies have been recently developed and proposed. RVS methods are simplified procedures that can be implemented rather quickly for preliminary assessment of building vulnerability without the need to perform a detailed model and numerical analysis. Their application is particularly useful in regions characterised by high seismicity or where an important share of the buildings was not designed according to seismic provisions. The outcome of RVS methods is a safety index, based on the data from simplified forms that are filled during visual inspection of the buildings. For this reason, the accuracy of the results could be significantly affected by building features that cannot be considered by such forms. To address this issue and to evaluate the effectiveness of RVS methods, this paper focuses on the comparison between the results of a specific RVS method and those from advanced numerical modelling and nonlinear analyses of masonry-infilled reinforced concrete buildings. Several case-study buildings were selected from a database developed in the framework of a recently concluded European project, which focused on the seismic risk assessment of residential buildings in Northern Algeria, a seismic prone region. The buildings are analysed using detailed structural finite element models, through both nonlinear static and dynamic analysis, considering also the influence of mechanical and geometrical properties of the masonry infills. The comparison results show that, despite the significant variability observed in the RVS vulnerability assessment outcomes, there is a fair overall match with the nonlinear analysis results, confirming the utility of RVS methods at an initial assessment stage, as well as the need for further extended validation research efforts.

Vulnerability Assessment of non-engineered houses related to earthquake in West Pasaman District

The earthquake on February 25, 2022, in West Pasaman resulted in damage to people’s houses as well as fatalities. The quake happened just under the Mount of Talamau, 18 km northeast of the city of Simpang Empat City, with a magnitude of 5.2 M. This earthquake was followed by small earthquakes that occurred until February 27, 2022. Damage to houses in the earthquake-affected area became the focus of attention in this research to assess the housing vulnerability related to the earthquake hazard. The vulnerability assessment of house buildings is critical in earthquake-prone areas because it can provide information about the impacts on the buildings. The vulnerability of house buildings is closely related to the potential for damage due to earthquake hazards. The benefit of the vulnerability assessment of house buildings is to arrange the mitigation action plan to reduce the level of damage to building structures. The method, in turn, can reduce the number of fatalities as well. Buildings with a high level of vulnerability to earthquakes are non-engineered or residential buildings that are built without considering essential factors in planning, such as the necessary technical requirements.

Vulnerability assessment of RC buildings with irregularities using probabilistic analysis

Modern construction comprises of large number of reinforced concrete structures with geometric irregularities. Even though these types of structures have good serviceability and aesthetic appearance, such structures show high vulnerability during earthquakes. The present study investigates the performance of multistorey RC buildings, with different irregularities under seismic excitations, using Pushover analysis. Fragility curve, defined as the probability of reaching or exceeding of a specific damage state under a seismic excitation, provides an estimate of possible damage during occurrence of an earthquake. Four structural models of multi storey reinforced concrete buildings with different configurations consisting of bare frame with plan irregularity, setback frame, set back frame with shear wall without openings and set back frame with shear wall with openings are considered. Three-dimensional models of the structures with different geometric irregularity are generated and pushover analysis of each model is carried out using the software ETABS. The capacity curves generated using pushover analysis are transformed into bilinear curves and the roof displacement at the yield and ultimate levels are obtained. The procedure asper ATC-40 is followed to find the performance point from this nonlinear analysis. Later the damage probability is calculated based on the damage state levels, and curves of fragility are generated. To quantify the damage of the structure using fragility curve, damage state levels are fixed as Slight, Moderate, Extreme and Collapse Damage Level. The results of pushover analysis indicate the effect of enhancement of the stiffness of the setback frame by providing shear wall without openings, but no significant effect in terms of stiffness and ductility while including shear wall with openings. Based on the damage state level chosen and fragility analysis of the four structural models, the structural system with setback frame with shear wall without openings has shown better performance.

The Seismic Vulnerability Assessment of Heritage Buildings: A Holistic Methodology for Masonry Churches

ABSTRACT 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.

Macromechanism Approach for Vulnerability Assessment of Buildings on Shallow Foundations in Liquefied Soils

The damage caused by seismic shaking and liquefaction-induced permanent ground deformation has conventionally been assessed as two separate problems often by different engineers. However, the two problems are inherently linked, since ground shaking causes liquefaction, and liquefaction-induced soil softening affects ground shaking. Modelling both problems within a single numerical model is complex for both the engineer and the software, and most finite element software only have the capabilities to address one of them. To improve the estimates of the seismic performance of buildings on liquefiable soil, a new sub-structuring approach is proposed called the macro-mechanism approach. This approach allows the soil-liquefaction-foundation-structure interaction to be considered in a series of sub-models accounting for the major nonlinear mechanisms of the system at a macro level. The proposed approach was implemented in the open-source finite element software OpenSees and then applied to a case study of a building where significant liquefaction- and shaking-induced damage was observed after the 1999 Mw 7.4 Kocaeli Earthquake. The case study building was also simulated using two different commercial software programs, the finite difference software FLAC, and the finite element software PLAXIS, by two different research teams. A comparison between the results from the macro-mechanism approach compared to full numerical models shows that the macro-mechanism approach can capture the extent of the foundation deformation and provide more realistic estimates of the building damage than full approaches since the FLAC and PLAXIS models consider elastic elements for the building.

Flood vulnerability assessment of urban buildings based on integrating high-resolution remote sensing and street view images

Urban flood risk management requires an extensive investigation of the vulnerability characteristics of buildings. Large-scale field surveys usually cost a lot of time and money, while satellite remote sensing and street view images can provide information on the tops and facades of buildings respectively. Thereupon, this paper develops a building vulnerability assessment framework using remote sensing and street view features. Specifically, a UNet-based semantic segmentation model, FSA-UNet (Fusion-Self-Attention-UNet) is proposed to integrate remote sensing and street view features and the vulnerability information contained in the images is fully exploited. And the building vulnerability index is generated to provide the spatial distribution characteristics of urban building vulnerability. The experiment shows that the mIoU of the proposed model can reach 82% for building vulnerability classification in Hefei, China, which is more accurate than the traditional semantic segmentation models. The results indicate that the integration of street view and remote sensing image features can improve the ability of building vulnerability assessment, and the model proposed in this study can better capture the correlation features of multi-angle images through the self-attention mechanism and combines hierarchy features and edge information to improve the classification effect. This study can support for disaster management and urban planning.

Integrated HBIM-GIS Models for Multi-Scale Seismic Vulnerability Assessment of Historical Buildings

The complexity of historical urban centres progressively needs a strategic improvement in methods and the scale of knowledge concerning the vulnerability aspect of seismic risk. A geographical multi-scale point of view is increasingly preferred in the scientific literature and in Italian regulation policies, that considers systemic behaviors of damage and vulnerability assessment from an urban perspective according to the scale of the data, rather than single building damage analysis. In this sense, a geospatial data sciences approach can contribute towards generating, integrating, and making virtuous relations between urban databases and emergency-related data, in order to constitute a multi-scale 3D database supporting strategies for conservation and risk assessment scenarios. The proposed approach developed a vulnerability-oriented GIS/HBIM integration in an urban 3D geodatabase, based on multi-scale data derived from urban cartography and emergency mapping 3D data. Integrated geometric and semantic information related to historical masonry buildings (specifically the churches) and structural data about architectural elements and damage were integrated in the approach. This contribution aimed to answer the research question supporting levels of knowledge required by directives and vulnerability assessment studies, both about the generative workflow phase, the role of HBIM models in GIS environments and toward user-oriented webGIS solutions for sharing and public use fruition, exploiting the database for expert operators involved in heritage preservation.

SISMO-Fast: energy-based method for rapid seismic vulnerability assessment of industrial precast RC buildings

Single-storey precast RC buildings not originally designed to withstand seismic actions showed their vulnerability during the Emilia Earthquake events (2012). The legislation that followed this catastrophic event has highlighted the need to assess and raise their seismic performance, even if interventions are limited to the connections between structural elements. The need to evaluate the conditions of existing buildings and to compare the effectiveness of risk mitigation interventions has highlighted the importance to have rapid assessment tools to check seismic vulnerability. The procedure proposed below begins by considering a simplified energy approach and allows the quantification of the seismic vulnerability of a precast RC building using few significant parameters.The proposal, for this specific type of building, works by comparing the characteristics of a new structure, assumed to be like the one to be assessed and designed for the seismic action of the specific site, to the existing structure to be assessed. The seismic vulnerability is subsequently defined in terms of the percentage of deviation of the real structure from the ideal one. The quantification of the percentage of deviation, based on macro-parameters, is estimated in terms of the capacity to absorb and resist the seismic input, described through energy. The SISMO-Fast method is based on the evidence of damage mechanisms observed during the site survey performed after the 2012 Emilia earthquake and other recent seismic events. The procedure has been used, for rapid seismic vulnerability assessment of some industrial precast RC buildings in different seismic areas, providing always reliable results.

Performance evaluation of high-rise apartment building using pushover analysis

Indonesia is a developing country that is experiencing rapid development growth. According to the Central Statistics Agency, in 2020 the population of Indonesia will be 270.20 million people. The increase in population from year-to-year results in increasingly narrow lands for development. Therefore, developers and businesspeople make the best use of this opportunity in the world of construction by carrying out developments, including high-rise apartments. As an earthquake-prone area, the planning process for buildings, especially tall buildings in Indonesia, must be carried out very carefully by considering the strength of the structure against high-intensity earthquake loads. Risk reduction strategies can be implemented through building vulnerability assessment by checking structural performance using pushover analysis. In this study, the performance of a 32-storey apartment building was examined using the pushover analysis method. The resulting calculation is that the performance of the structure is 0.0023 for the lateral direction and 0.0113 for the transverse direction. Through the ATC 40 method it is known that the result of structural performance is Damage Control, where after an earthquake the building is still habitable.

Seismic vulnerability assessment of RC frame structures subjected to seismic excitation: A review

Because of their unpredictable nature and high damage-causing ability, earthquakes pose a significant threat to buildings. As a result, loss of lives and significant loss of economy became a primary concern in many parts of the world. Damage to structures is one of the many reasons to examine their seismic behavior when subjected to seismic forces. The seismic vulnerability of a structure can also be defined as its vulnerability to damage caused by ground shaking of a certain intensity. A building fragility analysis is performed to assess its vulnerability. The analysis of structural fragility provides a better understanding of the response of structural and non-structural systems during seismic events. It also helps to reduce damage and the risk of loss of life. Fragility curves indicate the likelihood of failure when a building is subjected to earthquakes of varying magnitudes. This paper provides an overview of the studies published in the field of seismic vulnerability assessment of RC buildings using fragility curves. The adopted methods within the past studies were nonlinear static pushover analysis, nonlinear time history analysis, incremental dynamic analysis etc. This review study discusses the effects of aging, soil structure interaction, set back irregularities, effects of infill, effect of strong column and weak beam, soft story, construction quality etc. on the vulnerability of RC frame structures.

Seismic vulnerability assessment of RC buildings at compartment scale: the use of CARTIS form

Large-scale seismic vulnerability assessment methods allow to classify the vulnerability of groups of buildings according to recurring parameters. The parameters necessary for the application of these methods may come from the adoption of survey forms. The 1st level CARTIS survey form collects the parameters of an area (town compartment) characterized by homogeneity among building types. The variation of the parameters within the same compartment may lead to the definition of several typological-structural groups of buildings, which can be characterized by different vulnerability. Therefore, the assessment of the seismic vulnerability of a compartment requires knowing the distribution of different typologies and their relative structural performance. In this work the vulnerability is evaluated at town compartment level starting from the vulnerability of the RC building typologies, by applying the RE.SIS.TO® method to the data collected from the 1st level CARTIS forms. In particular, a tree chart representation, characterized by variable number of branches depending on the different number of possible choices allowed by CARTIS form, is proposed for data organization of the typological-structural groups of buildings.