Vulnerability Assessment Of Structures Research Articles

Modal-Based Fragility Analysis of High-Rise Tubular Structures: A Methodology for Vulnerability Assessment

This study addresses the limitations of current vulnerability assessment processes for tall buildings, which fail to incorporate the effects of higher modes and the resulting structural vulnerability to seismic hazards. Additionally, the extensive computational resources required for assessing tubular high-rise buildings make vulnerability assessments almost impossible. This study proposes a new methodology for assessing the modal-based structural vulnerability of high-rise reinforced concrete (RC) tubular buildings by incorporating nonlinear response and reducing computational effort. The proposed methodology discreetly develops the vulnerability information of each structural vibrational mode separately using nonlinear time history analysis rather than the linear Modal Response Spectrum Analysis (MRSA). The methodology includes steps for establishing vulnerability information for high-rise tubular buildings, and a case study of a 55-story RC building with core wall is presented to demonstrate the methodology. The vibrational modes of the building were decoupled and analyzed separately using single degree of freedom (SDOF) systems, and fragility curves were developed for three different limit states using various intensity measures. The obtained fragility relationships were compared with the curves of another structure of similar class. The results indicated good compatibility and significance of incorporating higher vibrational modes in assessment of structural vulnerability, thus, proposed methodology can be extended to any structural configuration of tubular buildings.

A novel framework for effective structural vulnerability assessment of tubular structures using machine learning algorithms (GA and ANN) for hybrid simulations

Abstract Seismic vulnerability assessments are conventionally conducted by using sophisticated nonlinear analytical models, leading to aggressive computational demands. Previous attempts were made to reduce computational efforts for establishing vulnerability assessment of structures; however, the area of super tall and tubular structures still faces considerable lack. Advent of efficient machine learning (ML) has enabled engineering practitioners to automate the processes for fragility analysis; however, its application for high-rise tubular structures is not yet exploited, and most implementations are limited to basic ML. In this work, an attempt was made to reduce computational demand for the fragility assessment process for tubular structures by employing genetic algorithms (GAs) for nonlinear structural modeling, and development of artificial neural network (ANN) using deep learning for fragility development. Consequently, a simple lumped parameter model had been developed using open-source code of ZEUS-NL, containing parameters selected by GA to acutely account for convoluted interactive behavior of structural systems and dynamic demands. Subsequently, incremental dynamic analysis (IDA) was performed on the optimized model. A new framework has been established to develop and train ANN architecture by amalgamating Weka’s capability of data preprocessing with deep learning. The established ANN model resulted in correlation coefficient of 0.9972 and R 2 of 0.95, demonstrating adequate performance.

Structural resilience evolution and vulnerability assessment of semiconductor materials supply network in the global semiconductor industry

In the context of the complex global supply chain situation, which faces significant challenges for the sustainable development of the semiconductor industry, such as energy and resource consumption, addressing risks and resilience issues, and sustainable resource management, etc. Therefore, this paper constructs a directed weighted supply network of semiconductor materials (gallium, germanium, and silicon) from an upstream perspective within the semiconductor industry chain during the period 2013–2022, which assesses the structural resilience under steady-state scenarios and vulnerability under the impact of risk attacks, and identifies resource power and resource center countries (or regions) within this network. The results demonstrate an improvement in the structural resilience of the gallium and germanium material supply networks, accompanied by an increase in vulnerability. There is a transition from a more centralized distribution of resource power among core countries (or regions) towards a more decentralized arrangement, while resource center countries (or regions) exhibit relative stability. In contrast, the structural resilience of the silicon material supply network declines, with a slight reduction in vulnerability. The shifts in resource power and resource center status among core countries (or regions) remain relatively stable. In conclusion, this paper presents policy recommendations aimed at enhancing the resilience of the global semiconductor materials supply chain.

A Review of Structural Vulnerability Assessment Methods in the Advent of a Tsunami

The interaction between hazard and exposure gives rise to risk. Tsunami risk assessment is derived from both hazard assessment and vulnerability assessment. Exposure can manifest in various aspects, such as social factors (e.g., population), environmental factors (e.g., agricultural areas), or economic factors (e.g., infrastructure). Our focus in this review paper is specifically on economic exposure, with an emphasis on structural vulnerability assessment. The approaches employed in tsunami vulnerability assessment are diverse. In this paper, we categorize them into simplified and in-depth methods, encompassing: (1) Empirical vulnerability functions, (2) Index-based approach, (3) Building tsunami vulnerability model (BTV).

Research on the importance and structural vulnerability assessment of RC frame components and robustness improvement methods

ABSTRACT To reasonably evaluate the robustness of RC frame structures, the ability to resist continuous collapse is improved. In this paper, the members’ contribution to the bearing capacity of the structure and the impact of the member’s failure are comprehensively considered, and the calculation method of the importance coefficient of the member is improved. At the same time, the structural vulnerability coefficient based on the change of the strain energy of the structure is combined with the reasonable assessment of the structural robustness through the two aspects of the member and the structure finishing. The redundancy analysis of the peripheral components of the failed components is carried out, and the low redundancy components are strengthened to improve the robustness of the structure to achieve the purpose of “strengthening the part and improving the whole”. On this basis, this paper evaluates the robustness of a four-story RC frame structure. It strengthens the low redundancy components under the influence of failure components to meet the requirements of improving the robustness of the structure, which verifies the rationality of the robustness evaluation method of the RC frame structure in this paper and the feasibility of improving the robustness of the structure.

Personalized Vulnerability Assessment of Customized Low-Rise Wood-Frame Residential Structures under Hurricane Wind Loads: A Flexible Scenario-Based Simulation Approach

Hurricanes are one of the costliest and deadliest weather and climate disasters that impact the United States, largely affecting the residential sector. Residential structures are essential for the health and safety of the community during a hurricane event. However, homeowners typically have to rely on general information and instructions to understand their level of risks. The knowledge of structural vulnerability to hurricanes at the individual residential building level is often limited, which hinders personalized disaster preparation and mitigation decision-making. To this end, a vulnerability assessment method is proposed for individual homeowners to create customized finite-element models that quantify wind damage of low-rise wood-frame residential structures under various scenarios using ANSYS 2020 R1 parametric design language. A case study was conducted to test the proposed methodology and investigate prevailing failure modes under different structural characteristics and wind scenarios. Specifically, the impacts of roof framing features and previous exposure to environmental conditions on the potential damage of residential buildings under hurricane wind loads were studied. Analysis results, including the percentage of failed sheathing, nailed connections and framing members, are used to inform personalized mitigation recommendations. The proposed customized vulnerability assessment may increase homeowners’ situational awareness of disasters and promote rational retrofitting decisions.

Preparing Medical Students for Anti-racism at the Bedside: Teaching Skills to Mitigate Racism and Bias in Clinical Encounters.

Systemic racism perpetuates health disparities and negatively impacts health care delivery and patient outcomes. Racism and bias can affect every aspect of clinical care, including history-taking, physical examination, laboratory interpretation, note-writing, oral presentation, and decision-making. Medical students must learn racism- and bias-mitigation skills early in their professional development to provide high-quality, equitable care. In November 2021, senior medical students and faculty with expertise in promoting health equity and justice in medicine designed and cotaught a Zoom-based, 75-minute, interactive session for second-year medical students. Participants prepared by reading assigned articles. Breakout rooms were used to facilitate small-group discussions. Session topics included use of a structural vulnerability assessment tool, examples of how bias can impact the physical exam, demonstration of how language can transmit bias, and skill practice using neutral instead of stigmatizing language. Forty second-year medical students participated in the session. Thirty-one students (78%) completed Likert-type surveys evaluating reaction and learning. Results showed improvements in students' perceptions of their abilities to assess for structural factors that influence health, recognize ways bias can impact clinical encounters, and apply skills to minimize bias in clinical care and decision-making. Providing opportunities for health care learners to think critically about how bias impacts patients and communities and equipping them with tools to begin dismantling exclusionary, racist practices in medicine are achievable and crucial to actualizing a just and equitable health system. This educational session can be adapted for training across health care professions and the educational continuum.

Methodology for the analysis of structural vulnerability of WUI settlements

As WUI fires have become a global concern, there is a growing need for engineering methodologies that lead to proactive fire management not only at the landscape level, but at all WUI scales. This paper presents a quantitative methodology for structural vulnerability assessment at the WUI settlement level that is based on 10 indicators, established for the different fire exposure phases a WUI area experiences (pre-impact, impact and fire transfer) as well as on other factors that can escalate vulnerability. As output, a Structural Vulnerability Index (SVI) for the entire analyzed area can be obtained. The methodology can not only assess vulnerability of WUI settlements in a quantitative way, but it can also quantify the effect of measures employed for the reduction of this vulnerability. Additionally, the methodology is suitable for comparison between different settlements or neighborhoods of the same area. A case study for the city of Barcelona, Spain, is presented, in which 9 WUI neighborhoods are analyzed and vulnerability reduction measures are prioritized.

Image-based 3D modeling-to-simulation of single-wythe masonry structure via reverse descriptive geometry

This study aims to develop an innovative image-based 3D modeling-to-simulation framework that can efficiently assess the hazard vulnerability of single-wythe masonry structures. Using the novel concept of ‘reverse descriptive geometry’, the framework utilizes 2D masonry wall images to model a 3D single-wythe masonry structure, subsequently converting it into a 3D discrete element model for the vulnerability assessment. The methodology involves segmenting all bricks in the 2D images, identifying the brick geometries by tracing the boundaries, and approximating those into polygons using the splitting method. By incorporating the wall orientations, the simplified 2D polygons are introduced into 3D space and subsequently extruded to a specified thickness. The corners between the walls, i.e., adjoining wythes, are realistically modeled with a type of structural masonry bond. The digitally constructed 3D masonry geometry is enriched with physical properties such as brick mass and mortar strengths, enabling a seamless 3D discrete element simulation to gauge the hazard vulnerability. The proposed framework is successfully applied to Stylite Tower, a heritage single-wythe masonry structure in Jordan. The results demonstrate a remarkable geometric accuracy achieved and further illustrate the structure's potential vulnerability under seismic events, highlighting the efficiency and efficacy of the developed framework. This study introduces a streamlined procedure leveraging a single 2D image per wall for 3D modeling of a structure, thus highly efficient. A discrete element modeling is adopted instead of finite element methods based on a continuum theory. Therefore, this approach accurately captures the discontinuous nature of masonry structures, resulting in a high fidelity in simulation. Furthermore, this study adopts an impulse-based dynamic simulation method that is far more computationally efficient and tolerant to geometric errors than the conventional discrete element method. Therefore, the proposed framework presents a significant advancement in the vulnerability assessment of masonry structures, providing a novel, efficient, and reliable methodology for engineering practice.

Retraction: Grey relational analysis method for typhoon vulnerability assessment of civil engineering structures based on the 2-tuple linguistic neutrosophic number.

Retraction: Grey relational analysis method for typhoon vulnerability assessment of civil engineering structures based on the 2-tuple linguistic neutrosophic number.

Empirical vulnerability estimation models considering updating the structural earthquake damage database

The seismic vulnerability of regional buildings is a fundamental index to effectively predict and estimate the seismic resilience of urban and rural areas. The structural empirical vulnerability database can be used to develop and generate relatively accurate multidimensional vulnerability models. With the development of instrument intensity and the updating of macroseismic intensity scales, the structural vulnerability assessment model established using the traditional regional structural empirical vulnerability database shows features of low accuracy. Therefore, using innovative methods to update the conventional vulnerability estimation model has become a fundamental scientific problem to be urgently solved. In this study, the mixed effects of instrument intensity and macrointensity and their evaluation scale were sufficiently considered, and the traditional vulnerability level quantification scale was improved. The structural empirical vulnerability database of three typical earthquakes in China (Wenchuan in 2008, Yushu in 2010, and Jiuzhaigou in 2017) has been comprehensively updated, and the multiscale statistical and computational model has been developed. A nonlinear regression model based on multidimensional vulnerability quantification parameters was proposed. A comparison model for predicting the actual seismic vulnerability of four types of buildings considering typical earthquakes was developed. The traditional vulnerability index algorithm was updated, and the point cloud and strip domain quantitative model based on the updated empirical vulnerability database (27,394 buildings) was established.

A Methodology for Assessing the Component-Level Fragility Curves and Its Application to a Class of Integral Abutment Bridges

Seismic vulnerability assessment of structures is a major research area and the output, i.e., fragility curves (FCs), within a probabilistic framework, devises effective seismic disaster mitigation. The present study proposes a novel methodology for obtaining the structural component-level FC through two new approaches with respect to the assessment of seismic demand and the computation of fragility. The present study evolves an existing nonlinear static method by a few steps to be able to assess the probabilistic demands and develops a numerical computation technique that exploits the actual profiles of the evaluated distributions of the structural capacity and demand data in a study to obtain the fragility magnitudes. The substitute methodology is implemented to derive the FCs of a class of integral abutment bridges while assessing the demands in a simple manner and avoiding the complexities of dynamic analysis and yet with reliable precision as well as averting the misjudgment of fragilities stemming from the lognormal or normal fit on the data, which are practically very rough fit or misfit to it, as imposed in the traditional fragility formulation.

Soil structural vulnerability: Critical review and conceptual development

Soil structure affects a range of soil functions (e.g., water, air, heat, and nutrient transport) and ecosystem services (e.g., production, climate regulation). Agricultural intensification is a dominant factor in global soil structural degradation. Understanding the vulnerability of soils to structural degradation may be important to land use planning and identifying management practices that mitigate the risk of degradation. We review the current methods for assessing soil structural vulnerability and the influencing factors, focussing on soil compaction and aggregate breakdown as two key measures of structural degradation. Methods for assessing risk of soil structural degradation and management practices affecting the risk are also discussed. Critical research gaps are identified, including the lack of studies that demonstrate the link between soil structural vulnerability and loss of soil functions or ecosystem services. Our review of the literature identified that the terms susceptibility, vulnerability, and risk are often used interchangeably. We propose definitions that can be used to distinguish these terms. Soil properties (relatively static), soil wetness, and land use stress (e.g., climate and management practices) are progressively included in the assessments of soil structural susceptibility, vulnerability, and risk. Existing indicators for assessing soil structural vulnerability may not be suitable to predict potential effects on ecosystem services. We highlight that soil structural vulnerability assessments should focus on key soil structural indicators (e.g., pore network-based hydraulic properties) affecting soil functions and ecosystem services. Both the state (i.e., condition) of soil structure and its vulnerability should be included for assessing soil structural degradation. To overcome the limitations of previous assessments, we developed a conceptual model linking soil structural vulnerability assessment to loss of soil functions and ecosystem services. Our review provides insights on assessment metrics and frameworks to develop management practices that improve soil structure and delivery of ecosystem services.

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.

Grey relational analysis method for typhoon vulnerability assessment of civil engineering structures based on the 2-tuple linguistic neutrosophic number.

As one of the severe natural disasters, typhoon hazard brings tremendous tragedy to human beings. The foreland in the southeast of China is one of the most typhoon prone areas in the world. There are amount of damage of civil engineering structures induced by typhoon every year. Especially for the spacious villages, the low-rise buildings are vulnerable to typhoon so that many of them are destroyed regionally. The typhoon vulnerability assessment of civil engineering structures is a classical multiple attribute group decision making (MAGDM) issues. In this paper, the 2-tuple linguistic neutrosophic number grey relational analysis (2TLNN-GRA) method is built based on the grey relational analysis (GRA) and 2-tuple linguistic neutrosophic sets (2TLNSs) with incomplete weight information. For deriving the weight information of the attribute, an optimization model is built on the basis of the GRA, by which the attribute weights can be decided. Then, the optimal alternative is chosen through calculating largest relative relational degree from the 2-tuple linguistic neutrosophic number positive ideal solution (2TLNNPIS) which considers both the largest grey relational coefficient (GRC) from the 2TLNNPIS and the smallest GRC form 2-tuple linguistic neutrosophic number negative ideal solution (2TLNN NIS). Then, combine the traditional fuzzy GRA model with 2TLNNSs information, the 2TLNN-GRA method is established and the computing steps for MAGDM are built. Finally, a numerical example for typhoon vulnerability assessment of civil engineering structures has been given and some comparisons is used to illustrate advantages of 2TLNN-GRA method.

SLaMA-URM method for the seismic vulnerability assessment of UnReinforced Masonry structures: Formulation and validation for a substructure

An analytical procedure based on the SLaMA (Simplified Lateral Mechanism Analysis) method is proposed for the seismic vulnerability assessment of UnReinforced Masonry (URM) structures. The procedure considers an equivalent frame discretization for the structure (pier, spandrel, and joint elements) and includes: (i) the evaluation of moment‒rotation capacity curves at each pier-spandrel subassembly; (ii) the assessment of the hierarchy of strength in each subassembly; and (iii) the calculation of the structure capacity curve according to the expected failure mechanism. Validation of the proposed SLaMA-URM procedure is achieved in a one-story URM substructure tested under lateral cyclic loading. The analytical predictions are compared with numerical ones from a 2D continuous finite element (FE) model based on a macro-modelling strategy. The flexural capacity of the components is estimated using a monolithic beam analogy, and the results compared with those from traditional sectional analysis. The influence of the substructure geometry on the hierarchy of strength at the subassembly and global levels is investigated. An analytical formulation of the pier-spandrel joint strength is also proposed to be considered in the assessment of the hierarchy of strength. The method is validated for a one-story substructure subjected to lateral in-plane loading. Results, in terms of crack patterns and capacity curves, are in relatively good agreement with the experimental and FE results, even when a bilinear curve approximation is used. The potential of the SLaMA-URM method for the seismic assessment of URM buildings is demonstrated, whose application to a larger URM structure is planned as a subsequent study.

An expeditious tool for the vulnerability assessment of masonry structures in post-earthquake reconstruction

AbstractPost-earthquake reconstruction activities need tools for assessing the vulnerability of structures, based on visual inspection and quick survey. So far, the public administrations in charge of granting the funds and monitoring reconstruction have adopted different methods taken from scientific literature or developed ad hoc for specific events. The time is ripe for a standard method to be developed, treasuring from the lessons learned in the field. This paper proposes an expeditious tool based on visual survey for the assessment of the seismic vulnerability of unreinforced masonry buildings, starting from available methods, whose parameters were reassessed and recalibrated, and scientific evidence from recent literature. The influence of the main structural features was considered to calculate a vulnerability index in the 0–100 range. The effects of materials and arrangement of masonry were quantitatively evaluated through the masonry quality index, which represents an advancement with respect to current practice. The method was validated on a sample of 50 masonry aggregates and nearly 200 structural units of L’Aquila, Italy, where reconstruction is underway after a destructive earthquake in 2009. The sample is representative of the built heritage of other earthquake prone areas in Italy and many European Countries and the proposed method is a step forward the development of a standard tool to be used in future post-earthquake reconstruction scenarios.

Vulnerability assessment and collapse simulation of unreinforced masonry structures subjected to sequential ground motions

Vulnerability assessment and collapse simulation of unreinforced masonry structures subjected to sequential ground motions

Analysis of an empirical seismic fragility prediction model of wooden roof truss buildings

To explore the vulnerability of wood roof truss buildings (WRTBs) under earthquake action, the empirical damage typical characteristics of 12,343.4 × 104 m2 and 21,490 buildings of this type of building that suffered different degrees of loss in 22 typical destructive earthquakes in China from 1993 to 2013 were observed and analysed. Based on the analysis methods of the nonlinear vulnerability model, probability statistics, and prediction model, a novel fragility probability matrix, plane, surface, nonlinear regression curve, and function model of different intensity zones under the latest Chinese macrointensity standard (GB/T 17742–2020, CMS-20) assessment were established, and vulnerability curve models were employed based on the damage ratio (DR) and actual cumulative damage probability (ACDP) parameters. According to 1993–1999, 2000–2010, and after 2011, the time-varying fragility specimen data were classified and censusly analysed. The fragility prediction curve models of DR and ACDP were performed using the probabilistic demand modal analysis method. Combined with the matrix probability and confidence interval calculation model, a novel regional mean fragility index domain model for typical structural (WRTB) vulnerability assessment was developed.

The effects of non-structural components on the dynamic characteristics and vulnerability of concrete structures using ambient vibration tests and Nakamura's criterion

From the past up to now, selecting a reliable structural system as well as analyzing and designing it accurately have considerably attracted the attention of researchers and engineers. An appropriate evaluation of the dynamic characteristics of the structures such as natural frequency and damping ratio has a considerable effect on the accurate analysis and design of structures. In addition, the vulnerability assessment of structures plays a significant role in selecting a resilient structural system against the seismicity of the area. In the light of these facts, one of the most important challenges is that the effects of non-structural components (NSCs) are commonly considered as a concentrated/distributed mass in most FE models and their stiffness and damping ratio are ignored. Therefore, this research aims to figure out the effects of NSCs on the dynamic characteristics and the vulnerability indices of concrete structures using microtremor measurements. For this purpose, the ambient vibrations of four concrete buildings (with two bending frame and two shear wall structural systems) during the construction process are measured in three independent stages: (1) after the completion of the structural system; (2) after the completion of the interior and exterior partition walls; (3) after the completion of the flooring, facade, and parapet elements (when the building is completely constructed). Afterward, to extract the dynamic characteristics and to compute the vulnerability indices of the structures, the measured microtremors are subjected to two signal processing techniques, i.e., floor spectral ratio (FSR) and random decrement method (RDM). It is observed that, by taking the effects of NSCs into account, the values of both dynamic characteristics of the concrete structures (i.e., natural frequency and damping ratio) are increased when the buildings are under the erection process. Furthermore, the obtained results for the concrete structures with the bending frame structural system demonstrate that the vulnerability index increases in the second stage compared with the first one, whereas it remarkably decreases in the third stage compared with the second one. Reciprocally, the obtained vulnerability indices for the concrete structures with the shear wall structural system show a similar behavior.