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1
Grigoriu, M., e A. Radu. "Are seismic fragility curves fragile?" Probabilistic Engineering Mechanics 63 (gennaio 2021): 103115. http://dx.doi.org/10.1016/j.probengmech.2020.103115.
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Wu, Yun Dan, Xiao Yao e Shi Jun Zhou. "Seismic Fragility Analysis for Typical Multi-Span Simply Supported Railway Box Girder Bridges". Applied Mechanics and Materials 858 (novembre 2016): 137–44. http://dx.doi.org/10.4028/www.scientific.net/amm.858.137.
Testo completoAbstract (sommario):
Fragility curves for typical multi-span simply supported concrete box girder bridges in eastern China are presented. A set of bridge samples, of which five uncertain parameters are considered, is established using the Latin hypercube sampling. Nonlinear time history analyses are conducted to capture the structural response quantities. Probabilistic seismic demand models are formulated by quadratic regression analysis for the capacity/demand ratios. Fragility curves of bridge components are developed and the fragility of bridge system is evaluated using the first-order bound method. The results show that the columns and expansion bearings among bridge members are more fragile under earthquake excitation, and the bridge system is more fragile than any bridge component. The typical bridges have more than 50% probability when subjected to PGAs of 0.46, 0.58, 0.82, and 1.0g for four damage states, respectively. The fragility curves can be used for retrofit prioritization for this type of bridges.
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Kim, Beom-Jin, Minkyu Kim, Daegi Hahm, Junhee Park e Kun-Yeun Han. "Probabilistic Flood Assessment Methodology for Nuclear Power Plants Considering Extreme Rainfall". Energies 14, n. 9 (1 maggio 2021): 2600. http://dx.doi.org/10.3390/en14092600.
Testo completoAbstract (sommario):
Abnormal weather conditions due to climate change are currently increasing on both global and local scales. It is therefore important to ensure the safety of the areas where major national facilities are located by analyzing risk quantitatively and re-evaluating the existing major facilities, such as nuclear power plants, considering the load and capacity of extreme flood conditions. In this study, a risk analysis method is developed that combines flood hazard curves with fragility curves using hydraulic and hydrological models by GIS tools and the @RISK model for the probabilistic flood analysis of nuclear power plant sites. A two-dimensional (2D) analysis is first carried out to estimate flood depths in various watershed scenarios, and a representative hazard curve for both external and internal flooding is made by applying a verified probability distribution type for the flood watersheds. For the analysis of flooding within buildings, an internal grid is constructed using GIS with related design drawings, and based on the flood depth results of the 2D analysis, a hazard curve for the representative internal inundation using a verified probability distribution type is presented. In the present study, walkdowns with nuclear experts are conducted around the nuclear power plant area to evaluate the fragile structures and facilities under possible flooding. After reviewing the 2D inundation analysis results based on the selected major equipment and facilities, the zones requiring risk assessment are re-assigned. A fragility curve applying probability distribution for the site’s major equipment and facilities is also presented. Failure risk analysis of the major facilities is then conducted by combining the proposed hazard and fragility curves. Results in the form of quantitative values are obtained, and the indicators for risks as well as the reliability and optimal measures to support decision-making are also presented. Through this study, it is confirmed that risk assessment based on the proposed probabilistic flood analysis technique is possible for flood events occurring at nuclear power plant sites.
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Wijayanti, Erlin, Stefanus Kristiawan, Edy Purwanto e Senot Sangadji. "Seismic Vulnerability of Reinforced Concrete Building Based on the Development of Fragility Curve: A Case Study". Applied Mechanics and Materials 845 (luglio 2016): 252–58. http://dx.doi.org/10.4028/www.scientific.net/amm.845.252.
Testo completoAbstract (sommario):
This study aims to determine the seismic vulnerability of 5th Building of Engineering Faculty, Sebelas Maret University by developing its fragility curves. Fragility curve is a measure of probabilistic seismic performance under various ground motion. The intensity of ground motion adopted in this study is median spectral displacement, , with lognormal standard deviation, βds as uncertainty parameter. The value of lognormal standard deviation is adopted from HAZUS. The parameters of median spectral displacements are identified from the capacity spectrum curve. The capacity curve obtained from non-linear static pushover analysis. Capacity curves can be converted into capacity spectrum to identify the location of the median spectral displacement at various damage states. The obtained fragility curves provide information on the probability of various damage states to occur when certain ground motion level strikes the building under study.
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Fatimah, Samreen, e Jenna Wong. "Sensitivity of the Fragility Curve on Type of Analysis Methods, Applied Ground Motions and Their Selection Techniques". International Journal of Steel Structures 21, n. 4 (26 giugno 2021): 1292–304. http://dx.doi.org/10.1007/s13296-021-00503-z.
Testo completoAbstract (sommario):
AbstractFragility curves are the primary way of assessing seismic risk for a building with numerous studies focused on deriving these fragility curves and how to account for the inherent uncertainty in the seismic assessment. This study focuses on a three-story steel moment frame structure and performs a fragility assessment of the building using a new approach called SPO2FRAG (Static Pushover to Fragility) that is based on pushover analysis. This new approach is further compared and contrasted against traditional nonlinear dynamic analysis approaches like Incremental Dynamic Analysis and Multiple Stripe Analysis. The sensitivity of the resulting fragility curves is studied against multiple parameters including uncertainties in ground motion, the type of analysis method used and the choice of curve fitting technique. All these factors influence the fragility curve behavior and this study assesses the impact of changing these parameters.
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Wu, Tong, Luyao Wang, Liyang Zhao, Gangping Fan, Jiahui Wang, Lihui Yin, Shuang Zhang e Shengchun Liu. "Seismic Fragility of a Multi-Frame Box-Girder Bridge Influenced by Seismic Excitation Angles and Column Height Layouts". Buildings 12, n. 3 (21 marzo 2022): 387. http://dx.doi.org/10.3390/buildings12030387.
Testo completoAbstract (sommario):
Curved multi-frame box-girder bridges with hinges are widely used in the United States due to the large spanning capacity, construction simplification and construction cost economy. This type of bridge frequently has the characteristics of column height asymmetry, adjacent bridge frames vibrating discrepancy. The combination of curved shape and random seismic excitation angles could aggravate the irregularity of the structural seismic response. In this study, an OpenSees model is established for an example bridge, and the hinge is taken as a key component to observe. The impacts of seismic excitation angles and column height layouts on fragility are investigated through the comparison of the fragility curves. The conclusions list the most unfavorable seismic excitation angles corresponding to the fragilities of bridge system, plug-type concrete elements in hinges, hinge restrainers, columns, abutment bearings as well as the secondary components, respectively. The symmetrical column height layout is proved to be beneficial to mitigate the damage risks of restrainers in intermediate hinges and reduce the fragility of the bridge system. This study can provide a reference for the rapid assessment of the fragile position and damage degree of bridges through structural configuration and shape, as well as the seismic excitation angle.
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Kaplan, Stan, Vicki M. Bier e Dennis C. Bley. "A note on families of fragility curves—is the composite curve equivalent to the mean curve?" Reliability Engineering & System Safety 43, n. 3 (gennaio 1994): 257–61. http://dx.doi.org/10.1016/0951-8320(94)90029-9.
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Choi, Seung Hun, Hee Jung Ham e Sungsu Lee. "Assessment of Building Vulnerability Curve Subjected to Debris-Flow". Journal of the Korean Society of Hazard Mitigation 20, n. 5 (31 ottobre 2020): 11–20. http://dx.doi.org/10.9798/kosham.2020.20.5.11.
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In this study, the vulnerability curves for masonry and concrete frame buildings are assessed based on building fragility curves for the debris-flow caused by landslides on mountain slopes. The First-Order Second-Moment (FOSM) method is used to estimate the building fragility curve (expressed as probability of damage exceedance) subjected to debris-flow. In this method, the horizontal displacement of a building impacted by debris-flow and the statistics of resistance (i.e., building displacement) following four different damage states (i.e., slight, moderate, extensive, and complete) are utilized to estimate the building fragility curve. The building vulnerability curves (expressed as mean probability of damage) were evaluated based on the estimated building fragility curve and corresponding mean damage ratio for each damage state and were verified by calculating the root mean square error with datasets obtained from post-disaster damage assessment. In this study, the effects of structural material, type, and height on the building vulnerability curves were also studied. All vulnerability curves of buildings estimated in this study were fitted and databased using parameters of the log-normal cumulative distribution function and can be used to measure the performance of buildings in debris-flow prone areas as well as to provide information for risk and loss assessment.
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Waenpracha, Suthiwat, Piyawat Foytong, Anawat Suppasri, Supakorn Tirapat, Nuttawut Thanasisathit, Pongnathee Maneekul e Teraphan Ornthammarath. "Development of Fragility Curves for Reinforced-Concrete Building with Masonry Infilled Wall under Tsunami". Advances in Civil Engineering 2023 (14 marzo 2023): 1–15. http://dx.doi.org/10.1155/2023/8021378.
Testo completoAbstract (sommario):
A tsunami is a natural disaster that destroys structures and kills many lives in many countries in the world. A risk assessment of the building under a tsunami loading is thus essential to evaluate the damage and minimize potential loss. A crucial tool in risk assessment is the fragility curve. Most building fragility curves for tsunami force were developed using survey building damaged data. This research proposed a method for developing fragility curves under tsunami loading based on the analytical building model data. In the development, the generic building was a one-story reinforced-concrete building with masonry-infilled walls constructed from the structural index, popularly built as residential buildings along the west coast of southern Thailand. Three damage levels were investigated: damage in masonry infill walls, damage in primary structures, and collapses. The masonry infill wall was modeled using multisprings to represent the load-bearing behavior due to tsunami with a hydrodynamic pattern. The fragility curves were developed using the maximum likelihood method and considering the uncertainty due to masonry infill wall type, tsunami flow direction, and tsunami flow velocity. The developed fragility curve agrees well with the empirical tsunami fragility curve of a one-story reinforced-concrete building damage data in Thailand from the 2004 Tsunami. The developed fragility functions could be adopted for assessing tsunami risk assessment and disaster mitigation for similar structures against different tsunami scenarios in the future.
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Dang, Thuat-Cong, Thien-Phu Le e Pascal Ray. "Seismic fragility curves based on the probability density evolution method". Vietnam Journal of Mechanics 39, n. 2 (21 giugno 2017): 177–89. http://dx.doi.org/10.15625/0866-7136/10208.
Testo completoAbstract (sommario):
A seismic fragility curve that shows the probability of failure of a structure in function of a seismic intensity, for example peak ground acceleration (PGA), is a powerful tool for the evaluation of the seismic vulnerability of the structures in nuclear engineering and civil engineering. The common assumption of existing approaches is that the fragility curve is a cumulative probability log-normal function. In this paper, we propose a new technique for construction of seismic fragility curves by numerical simulation using the Probability Density Evolution Method (PDEM). From the joint probability density function between structural response and random variables of a system and/or excitations, seismic fragility curves can be derived without the log-normal assumption. The validation of the proposed technique is performed on two numerical examples.
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Nagata, Makoto, Masuhiro Beppu, Hiroyoshi Ichino e Harumi Yashiro. "Proposal on risk assessment of reinforced concrete structures subjected to explosive loads". International Journal of Protective Structures 8, n. 3 (settembre 2017): 407–32. http://dx.doi.org/10.1177/2041419617721549.
Testo completoAbstract (sommario):
This study proposes an evaluation method to assess the risk of a reinforced concrete structure subjected to an explosive load such as that resulting from a terrorist bombing attack. First, a hazard curve that represents the relationship between the frequency of explosive incidents and the explosive mass was evaluated based on the statistics of terrorist bombing incidents. Second, to evaluate the damage state of the reinforced concrete structure due to the explosive load, fragility curves for the reinforced concrete members, such as beams, columns, and slabs, were evaluated using a single-degree-of-freedom model and a rotational capacity–based criterion. The fragility curve shows the relationship between the damage probability level, such as “no damage,” “small damage,” “collapse,” and an explosive mass. The total failure probability of the reinforced concrete structure was estimated by superposing the fragility curves of the members and by incorporating the reducing effect of floor slabs in the reinforced concrete structure on the blast load. A loss curve was drawn based on the damage state of the reinforced concrete structure by assuming the number of human lives lost and the reinforced concrete structure in each damage state. A risk curve was then derived by combining the hazard curve with the loss curve.
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Karimi, F., A. Ranjbaran e P. Amirian. "Effect of R, µ and T on the Fragility Curves for Two Spans Reinforced Concrete Highway Bridges". Journal of Applied Engineering Sciences 9, n. 2 (1 dicembre 2019): 145–54. http://dx.doi.org/10.2478/jaes-2019-0020.
Testo completoAbstract (sommario):
Abstract Fragility curves are useful tools for evaluating the probability of structural damage due to earthquakes as a function of ground motion indices. The force reduction factor (R) is one of the seismic design parameters that determine the nonlinear performance of building structures during strong earthquakes. R factor itself is mostly a function of displacement ductility (µ), natural period of a structure, and soil conditions. A statistical method (Path Analysis) is proposed for the first time to determine the effect of R, µ and T on the column fragility curve parameters of typical box girder, two spans reinforced concrete highway bridge class. An analytical approach was adopted to develop the fragility curves based on numerical simulation. The R, µ and fundamental period T have been used to characterize different bridge configurations. The total, direct, and indirect effects of the variables as having significant effect on fragility curve parameters were identified.
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Mathews, Merin, B. R. Jayalekshmi e Katta Venkataramana. "Probabilistic Analysis of RC Buildings Based on Incremental Dynamic Analysis". IOP Conference Series: Earth and Environmental Science 1149, n. 1 (1 maggio 2023): 012007. http://dx.doi.org/10.1088/1755-1315/1149/1/012007.
Testo completoAbstract (sommario):
Abstract Earthquake is a natural disaster that can induce immense damage to properties and human lives. Fragility curve, defined as the probability of reaching or exceeding a specific damage state under an earthquake excitation, provides a prediction of damage that may occur during an earthquake. Incremental Dynamic Analysis Curve (IDA curve) developed from Incremental Dynamic analysis can be considered as the initial step of fragility curve development. The present study summarises the development of IDA curve for a RC building considering maximum roof displacement and storey drift as Damage Measure (DM) and peak ground acceleration as Intensity Measure (IM). The fragility curves developed using incremental dynamic analysis provide an overview of the probability of exceedance of damage limits in an existing building when acted upon by different levels of earthquake excitations and the performance level can be improved by incorporating appropriate design changes.
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Mansouri, Iman, Jong Wan Hu, Kazem Shakeri, Shahrokh Shahbazi e Bahareh Nouri. "Assessment of Seismic Vulnerability of Steel and RC Moment Buildings Using HAZUS and Statistical Methodologies". Discrete Dynamics in Nature and Society 2017 (2017): 1–16. http://dx.doi.org/10.1155/2017/2698932.
Testo completoAbstract (sommario):
Designer engineers have always the serious challenge regarding the choice of the kind of structures to use in the areas with significant seismic activities. Development of fragility curve provides an opportunity for designers to select a structure that will have the least fragility. This paper presents an investigation into the seismic vulnerability of both steel and reinforced concrete (RC) moment frames using fragility curves obtained by HAZUS and statistical methodologies. Fragility curves are employed for several probability parameters. Fragility curves are used to assess several probability parameters. Furthermore, it examines whether the probability of the exceedence of the damage limit state is reduced as expected. Nonlinear dynamic analyses of five-, eight-, and twelve-story frames are carried out using Perform 3D. The definition of damage states is based on the descriptions provided by HAZUS, which gives the limit states and the associated interstory drift limits for structures. The fragility curves show that the HAZUS procedure reduces probability of damage, and this reduction is higher for RC frames. Generally, the RC frames have higher fragility compared to steel frames.
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Tavazo, H. A., e A. Ranjbaran. "Fragility Analysis of 3D Reinforced Concrete Frames Based on Endurance Time Method with Derived Standard Deviation". Journal of Earthquake and Tsunami 11, n. 04 (ottobre 2017): 1750011. http://dx.doi.org/10.1142/s1793431117500117.
Testo completoAbstract (sommario):
Fragility curves have been developed for seismic vulnerability analysis of structures and can be generated in empirical and analytical forms. To develop analytical fragility curve, the incremental dynamic analysis (IDA) method is considered as an applicable tool for seismic analysis; however, in the cases with high modeling complexity, the computational cost of the IDA method may be very high. Therefore, an alternative method called as endurance time (ET) method can be effectively used for fragility analysis. In this study, a new, accurate and cost effective method has been introduced in order to develop analytical fragility curves based on the ET method. The results reveal that ET-based fragility curves generally agree well with IDA-based fragility curves. In addition, it is revealed that a highly matched fragility function can be fitted on fragility points using ET-based fragility analysis (due to continuity of these points in every 0.01 of IM changes). It is concluded that ET analysis offers convenient and easy access to median and logarithmic standard deviation of IMs and thus fragility function can be produced easily based on these statistical parameters. Furthermore, a new ET-based methodology is presented to consider the previously experienced earthquakes (PEEQs) in generating fragility surfaces.
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Sarli, Prasanti Widyasih, Pramudita Satria Palar, Yuni Azhari, Andri Setiawan, Yongky Sanjaya, Sophia C. Sharon e Iswandi Imran. "Gaussian Process Regression for Seismic Fragility Assessment: Application to Non-Engineered Residential Buildings in Indonesia". Buildings 13, n. 1 (27 dicembre 2022): 59. http://dx.doi.org/10.3390/buildings13010059.
Testo completoAbstract (sommario):
Indonesia is located in a high-seismic-risk region with a significant number of non-engineered houses, which typically have a higher risk during earthquakes. Due to the wide variety of differences even among parameters within one building typology, it is difficult to capture the total risk of the population, as the typical structural engineering approach to understanding fragility involves tedious numerical modeling of individual buildings—which is computationally costly for a large population of buildings. This study uses a statistical learning technique based on Gaussian Process Regression (GPR) to build the family of fragility curves. The current research takes the column height and side length as the input variables, in which a linear analysis is used to calculate the failure probability. The GPR is then utilized to predict the fragility curve and the probability of collapse, given the data evaluated at the finite set of experimental design. The result shows that GPR can predict the fragility curve and the probability of collapse well, efficiently allowing rapid estimation of the population fragility curve and an individual prediction for a single building configuration. Most importantly, GPR also provides the uncertainty band associated with the prediction of the fragility curve, which is crucial information for real-world analysis.
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Kohns, Julia, Lothar Stempniewski e Alexander Stark. "Fragility Functions for Reinforced Concrete Structures Based on Multiscale Approach for Earthquake Damage Criteria". Buildings 12, n. 8 (16 agosto 2022): 1253. http://dx.doi.org/10.3390/buildings12081253.
Testo completoAbstract (sommario):
For seismic risk analysis, reliable predictions and estimations of earthquake damage and seismic behaviour of buildings are essential. A common method is the use of fragility curves. In this paper, fragility functions are developed based on various numerical damage criteria for five defined damage grades, from slight to destruction. The proposed new multiscale approach establishes a correlation between observed damage patterns due to foreign earthquakes and the seismic response of the building using thresholds for material-specific and global characteristics. This approach takes into account various possible damage patterns on different scales more comprehensively than the well-known approach of displacement criteria. Moreover, the approach is universal and adaptable for building classes as well as region-specific material and system characteristics. Several damage criteria with their defined limit values are assigned to the five proposed damage grades, whereby quantity and distribution of the exceeded criteria are relevant, since the first occurrence does not always lead to damage. With the new approach, damages that are not evident in the pushover curve in terms of strength degradation can be detected and taken into account for the damage thresholds. The derived displacement values associated with the damage levels are the basis for developing fragility functions. The results—damage criteria, pushover curves with damage grades, capacity curves as well as fragility functions and parameters—are presented for a four-storey reinforced concrete frame building. These results are discussed and validated with data from the literature. Comparisons to existing fragility functions in the literature show that our developed fragility functions are mostly located in the middle range, graphically as well as for the curve parameters. This specific example was chosen to present our multiscale approach, but for general building classes, numerous simulations with varying characteristics are essential and result in a higher standard deviation of the final fragility curves.
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Suppasri, A., S. Koshimura e F. Imamura. "Developing tsunami fragility curves based on the satellite remote sensing and the numerical modeling of the 2004 Indian Ocean tsunami in Thailand". Natural Hazards and Earth System Sciences 11, n. 1 (20 gennaio 2011): 173–89. http://dx.doi.org/10.5194/nhess-11-173-2011.
Testo completoAbstract (sommario):
Abstract. The 2004 Indian Ocean tsunami damaged and destroyed numerous buildings and houses in Thailand. Estimation of tsunami impact to buildings from this event and evaluation of the potential risks are important but still in progress. The tsunami fragility curve is a function used to estimate the structural fragility against tsunami hazards. This study was undertaken to develop fragility curves using visual inspection of high-resolution satellite images (IKONOS) taken before and after tsunami events to classify whether the buildings were destroyed or not based on the remaining roof. Then, a tsunami inundation model is created to reconstruct the tsunami features such as inundation depth, current velocity, and hydrodynamic force of the event. It is assumed that the fragility curves are expressed as normal or lognormal distribution functions and the estimation of the median and log-standard deviation is performed using least square fitting. From the results, the developed fragility curves for different types of building materials (mixed type, reinforced concrete and wood) show consistent performance in damage probability and when compared to the existing curves for other locations.
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Urlainis, Alon, e Igal M. Shohet. "Development of Exclusive Seismic Fragility Curves for Critical Infrastructure: An Oil Pumping Station Case Study". Buildings 12, n. 6 (16 giugno 2022): 842. http://dx.doi.org/10.3390/buildings12060842.
Testo completoAbstract (sommario):
Fragility curves are a common tool to appraise the expected damage to critical infrastructure (CI) after an earthquake event. Previous studies offer fragility curve parameters for CI that are suitable for a vast range of systems, without an in-depth examination of the system architecture and subcomponents. These curves are applicable in cases where a thorough analysis is not required or when the information related to a single system is poor. This paper proposes an original approach and presents a comprehensive methodology for developing exclusive fragility curves for critical infrastructure systems. In the proposed methodology, the fragility curves are developed by a decomposition of the system into its main subcomponents and determination of the failure mechanisms. The derivation of the fragility parameters includes failure analysis for each damage state by a Fault Tree Analysis and approximation of the fragility parameters in accordance with the rate of exceedance. The implementation of the methodology is demonstrated by a case study with three alternatives of an oil pumping plant configuration. It was found that a change of a subcomponent has an effect on the derived values of the fragility parameters. Moreover, the variances in the fragility parameters have implications for the effectiveness of each alternative to resist different levels of severity.
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Hanggara, Dicky, e Anil Christopher Wijeyewickrema. "Vulnerability assessment of reinforced concrete buildings in Indonesia subjected to tsunami inundation forces". International Journal of Disaster Resilience in the Built Environment 11, n. 2 (12 dicembre 2019): 204–18. http://dx.doi.org/10.1108/ijdrbe-09-2019-0062.
Testo completoAbstract (sommario):
Purpose This paper aims to evaluate the vulnerability of typical low-rise reinforced concrete (RC) buildings located in Indonesia subjected to tsunami loading. Design/methodology/approach The vulnerability of typical three-story RC buildings located in Indonesia subjected to tsunami loading is discussed using fragility curves. Buildings without openings in all stories and buildings with openings in the first story are considered. The fragility curves are obtained by performing tsunami pushover analysis for several load cases, using different tsunami load estimation standards and references. The generalized linear method is used as a curve fitting method to construct the fragility curves. Findings The fragility curves show that the three-story RC buildings without openings in all stories subjected to tsunami loading have a high probability of collapse. Openings in the first story will reduce the vulnerability of the buildings. Originality/value Fragility curves are obtained by carrying out tsunami pushover analysis to evaluate the vulnerability of typical three-story RC buildings located in Indonesia. The results of this study show the need to include tsunami loads in the design code for Indonesian buildings and the benefits of having openings in the first story of the building.
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Beheshti-Aval, S. B., E. Khojastehfar, M. Noori e M. R. Zolfaghari. "A comprehensive collapse fragility assessment of moment resisting steel frames considering various sources of uncertainties". Canadian Journal of Civil Engineering 43, n. 2 (febbraio 2016): 118–31. http://dx.doi.org/10.1139/cjce-2013-0491.
Testo completoAbstract (sommario):
Different sources of uncertainties contribute to the collapse and safety assessment of structures. In this paper, impact of construction quality (CQ) is considered in developing analytical collapse fragility curves for moment resisting steel frames. Furthermore, the interaction of this source of uncertainty with epistemic uncertainty inherent in modeling parameters, due to lack of knowledge and inaccuracy of predictor equations, is investigated. Beam strength, column strength, beam ductility, and column ductility meta-variables are defined as modeling parameters which are being suffered by informal uncertainty. Quadratic equations for the mean and the standard deviation of collapse fragility curves are derived by utilizing response surfaces, which are interpolated to analytically-derived values considering realizations for modeling variables and for various levels of construction quality. To the best of the authors’ knowledge, interaction of modeling and CQ uncertainty in analytical collapse fragility curve has not been considered in previous investigations. A fuzzy rule-based method is applied to employ the effects of uncertainty due to CQ. Using Monte Carlo simulation for the modeling variables and the construction quality index, and subsequently computing response surface coefficients via a fuzzy inference system, and finally deriving collapse fragility curve parameters through response surfaces, result in collapse fragility curves of structures. In developing these curves, different sources of uncertainties are involved, ranging from lexical to informal and stochastic types. It is concluded that neglecting the effects of these sources leads to the underestimation of collapse fragility probability. This shows the importance of considering modeling and construction quality uncertainty effects on collapse fragility curves. It is shown that for a sample moment resisting steel frame collapse probability is increased 53% and 60% for 10% and 2% probability of exceedance in 50 years seismic hazard levels, respectively, while interaction of CQ and modeling uncertainties are considered in comparison with neglecting them. Otherwise, if only modeling uncertainty is involved, this increment is evaluated at 42% and 16%, respectively for the aforementioned probabilities of exceedance.
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Sarraf Shirazi, Reihaneh, Gokhan Pekcan e Ahmad Itani. "Analytical Fragility Curves for a Class of Horizontally Curved Box-Girder Bridges". Journal of Earthquake Engineering 22, n. 5 (23 gennaio 2017): 881–901. http://dx.doi.org/10.1080/13632469.2016.1264325.
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LIN, J. H. "SEISMIC FRAGILITY ANALYSIS OF FRAME STRUCTURES". International Journal of Structural Stability and Dynamics 08, n. 03 (settembre 2008): 451–63. http://dx.doi.org/10.1142/s0219455408002740.
Testo completoAbstract (sommario):
A seismic fragility analysis of structures is essential to prediction of the building behavior that is likely to occur during earthquakes. Normally, the probability of failure of a structure over a specified period of time is obtained through a convolution of the fragility curve with the seismic hazard curve for the structure site. The fragility models and damage states probabilities serve as a basis for improving the structural codes and performance-based design. Thus, there is a need for relatively simple procedures for evaluating fragility data for decision-making. In this study, the peak story drifts of a building structure during earthquakes are used as an indicator of structural demands. An analytical solution for evaluating the statistical characteristics of peak story drifts of frame structures during earthquakes is proposed. Based on it, an approximate approach to constructing the seismic fragility curves for various states of damage for frame structures is developed.
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Anvarsamarin, Ali, Fayaz Rahimzadeh Rofooei e Masoud Nekooei. "Soil-Structure Interaction Effect on Fragility Curve of 3D Models of Concrete Moment-Resisting Buildings". Shock and Vibration 2018 (2018): 1–13. http://dx.doi.org/10.1155/2018/7270137.
Testo completoAbstract (sommario):
This paper presents the probabilistic generation of collapse fragility curves for evaluating the performance of 3D, reinforced concrete (RC) moment-resisting building models, considering soil-structure interaction (SSI) by concentration on seismic uncertainties. It considers collapse as the loss of lateral load-resisting capacity of the building structures due to severe ground shaking and consequent large interstory drifts intensified by P-Δ effects as well as the strength and stiffness deterioration of their lateral load carrying systems. The estimation of the collapse performance of structures requires the relation between the intensity measure (IM) and the probability of collapse that is determined using the generated collapse fragility curves. Considering a number of 6-, 12-, and 18-story, 3D, RC moment-resisting buildings, two scalar IMs are employed to estimate their collapse fragility curve. On the other hand, the effect of the site soil type on the collapse fragility curves was taken into account by considering the soil-structure interaction. According to the obtained results, adopting the average of spectral acceleration (Saavg) intensity measure is more efficient in capturing the effect of the inherent uncertainties of the strong ground motions on the structural response parameters. In addition, considering the SSI for soil type D with shear-wave velocity of 180 m/s to 360 m/s reduces the median of intensity measure (IM = Sa(T1)) of fragility curve in 6-, 12-, and 18-story buildings by 4.92%, 22.26%, and 23.03%, respectively.
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Irfan, Zu, Abdullah e Moch Afifuddin. "Development of fragility curve based on incremental dynamic analysis curve using ground motion Aceh earthquake". E3S Web of Conferences 340 (2022): 02001. http://dx.doi.org/10.1051/e3sconf/202234002001.
Testo completoAbstract (sommario):
History records that Aceh has been hit by earthquakes several times, including the largest recorded, on December 26, 2004 with a magnitude of 9.3 SR. In connection with the history of disasters that have occurred, there is a need for safety and disaster preparedness. It is very important to conduct a feasibility study of the existing public buildings used in disaster preparedness for vulnerability against earthquakes. The type of building damage caused can predicted by referring to the fragility curve. This research conducted on evaluating the seismic performance of existing buildings in Banda Aceh City by developing a fragility curve based on Incremental Dynamic Analysis (IDA). The existing buildings that are the main focus of this study include the Tsunami Vertical Evacuation (TVE) of Lambung, TVE Alu Deah Teungoh, TVE TDMRC, SDN 48 Banda Aceh, SMPN 11 Banda Aceh, Baiturrahim Ulee Lheu Mosque, and the Subulussalam Punge Mosque. The IDA method is applied to predict and estimate the performance of the structure using several ground motions. The resulting set of IDA curves were further analyzed to form the fragility curve. The fragility curve becomes the basis for assessing the seismic performance of building structures rationally.
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SHIBATA, Heki. "Aseismic Design and Fragility Curve". Journal of the Society of Mechanical Engineers 88, n. 795 (1985): 167–74. http://dx.doi.org/10.1299/jsmemag.88.795_167.
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Sandoli, A., G. P. Lignola, B. Calderoni e A. Prota. "Fragility curves for Italian URM buildings based on a hybrid method". Bulletin of Earthquake Engineering 19, n. 12 (18 giugno 2021): 4979–5013. http://dx.doi.org/10.1007/s10518-021-01155-4.
Testo completoAbstract (sommario):
AbstractA hybrid seismic fragility model for territorial-scale seismic vulnerability assessment of masonry buildings is developed and presented in this paper. The method combines expert-judgment and mechanical approaches to derive typological fragility curves for Italian residential masonry building stock. The first classifies Italian masonry buildings in five different typological classes as function of age of construction, structural typology, and seismic behaviour and damaging of buildings observed following the most severe earthquakes occurred in Italy. The second, based on numerical analyses results conducted on building prototypes, provides all the parameters necessary for developing fragility functions. Peak-Ground Acceleration (PGA) at Ultimate Limit State attainable by each building’s class has been chosen as an Intensity Measure to represent fragility curves: three types of curve have been developed, each referred to mean, maximum and minimum value of PGAs defined for each building class. To represent the expected damage scenario for increasing earthquake intensities, a correlation between PGAs and Mercalli-Cancani-Sieber macroseismic intensity scale has been used and the corresponding fragility curves developed. Results show that the proposed building’s classes are representative of the Italian masonry building stock and that fragility curves are effective for predicting both seismic vulnerability and expected damage scenarios for seismic-prone areas. Finally, the fragility curves have been compared with empirical curves obtained through a macroseismic approach on Italian masonry buildings available in literature, underlining the differences between the methods.
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Ahmad, Nursafarina, Azmi Ibrahim e Shahria Alam. "Analytical Seismic Fragility Curves for Reinforced Concrete Wall pier using Shape Memory Alloys considering maximum drift". MATEC Web of Conferences 258 (2019): 04001. http://dx.doi.org/10.1051/matecconf/201925804001.
Testo completoAbstract (sommario):
Fragility curves express the seismic vulnerability of bridge piers for different damage states at various earthquake intensities. A fragility curve typically gives a physical understanding of repair costs and functionally levels of a bridge pier. Shape memory alloys (SMAs) provide a promising alternative material in reducing the failure probability of a bridge pier. This study develops a family of seismic fragility curves for reinforced concrete (RC) wall piers reinforced with three different types of SMA rebar in plastic hinge regions. An incremental dynamic analysis (IDA) using a total of 20 earthquake ground motions was performed on a SMA-RC wall pier to evaluate its seismic performance. The maximum drift recorded for each ground motion was taken as the seismic performance demand parameter of interest in this study. The probabilistic seismic demand model (PSDM) was used to generate fragility curves for each RC-SMA wall pier. The results show that the different mechanical properties and type of SMAs affect the performance of RC-SMA wall pier.
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Zheng, Shan Suo, Wen Bo Li, Qian Li e Fan Wang. "Seismic Fragility Analysis of SRC Frame Structures". Applied Mechanics and Materials 166-169 (maggio 2012): 2042–45. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.2042.
Testo completoAbstract (sommario):
With the rapid development and extensive application of SRC (steel reinforced concrete) frame structures, the study on seismic fragility of SRC structure under earthquakes seems rather important. The seismic fragility of the SRC frame structures is studied by the method of Incremental Dynamic Analysis (IDA) in this paper. IDA method is conducted on 9 storey SRC frame structure to obtain the IDA curves of this model. Meanwhile, the seismic fragility of the model is analyzed to get the fragility curve. The result shows that IDA can describe the quantitative relationship between the exceeding probability of different states and damage degree of the target.
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He, Zhiming, e Qingjun Chen. "Vertical Seismic Effect on the Seismic Fragility of Large-Space Underground Structures". Advances in Civil Engineering 2019 (7 aprile 2019): 1–17. http://dx.doi.org/10.1155/2019/9650294.
Testo completoAbstract (sommario):
The measured vertical peak ground acceleration was larger than the horizontal peak ground acceleration. It is essential to consider the vertical seismic effect in seismic fragility evaluation of large-space underground structures. In this research, an approach is presented to construct fragility curves of large-space underground structures considering the vertical seismic effect. In seismic capacity, the soil-underground structure pushover analysis method which considers the vertical seismic loading is used to obtain the capacity curve of central columns. The thresholds of performance levels are quantified through a load-drift backbone curve model. In seismic demand, it is evaluated through incremental dynamic analysis (IDA) method under the excitation of horizontal and vertical acceleration, and the soil-structure-interaction and ground motion characteristics are also considered. The IDA results are compared in terms of peak ground acceleration and peak ground velocity. To construct the fragility curves, the evolutions of performance index versus the increasing earthquake intensity are performed, considering related uncertainties. The result indicates that if we ignore the vertical seismic effect to the fragility assessment of large-space underground structures, the exceedance probabilities of damage of large-space underground structures will be underestimated, which will result in an unfavorable assessment result.
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Carneiro, Raphael Felipe, Denise Maria Soares Gerscovich e Bernadete Ragoni Danziger. "Reconstructing oedometric compression curves for selecting design parameters". Canadian Geotechnical Journal 56, n. 5 (maggio 2019): 621–35. http://dx.doi.org/10.1139/cgj-2018-0018.
Testo completoAbstract (sommario):
The mineral structure of soft clays is extremely fragile. Sampling operations and laboratory handling cause unavoidable disturbance. Undisturbed sampling is a theoretical concept because the stress release imposes disturbance. Consolidation tests on disturbed samples provide one-dimensional (1D)-compression curves very different from field response, which leads to inaccurate settlement estimates. Among the approaches for curve reconstruction, Schmertmann’s method is probably the most commonly adopted in engineering practice. However, it presents difficulties in determining preconsolidation stress. The paper primarily addresses Schmertmann’s and Nagaraj et al.’s propositions and discusses their advantages and shortcomings. A new approach for reconstructing the 1D-compression curve is proposed with the main objective being its independence of the interpretation of the experimental results. The validity was examined by comparing the reconstructed curves with those obtained by other methods. Experimental results on high- and low-quality specimens have been analyzed as well. The results revealed that the reconstructed curves for the cases analyzed are almost unique and independent of specimen quality. The proposed method allows both graphical and analytical implementation and the reconstructed curves are unaffected by experimental curve interpretation.
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Ismael, Sarwar S., e Faris R. Ahmed. "Seismic Fragility Curves for Reinforced Concrete Dual System Buildings". ARO-THE SCIENTIFIC JOURNAL OF KOYA UNIVERSITY 11, n. 1 (23 giugno 2023): 149–56. http://dx.doi.org/10.14500/aro.11172.
Testo completoAbstract (sommario):
A seismic fragility curve is a visual representation that illustrates the likelihood of a structure surpassing a particular damage or performance limit state caused by an earthquake with a specific intensity or ground motion level. This curve is typically generated using probabilistic seismic hazard analysis and structural reliability analysis methods. It is based on statistical models that rely on past earthquake data and simulations of future earthquake scenarios to predict the structure or system’s behavior under seismic forces. In this study, the seismic performance of 30 stories of 95 m height dual system reinforced concrete buildings located in Erbil is evaluated by analyzing three distinct ground motions. A non-linear platform is used to simulate and analyze data, followed by the generation of seismic inter-story drift fragility curves using Incremental Dynamic Analysis. The buildings’ seismic structural performance is assessed based on five different performance levels, including operational phase, immediate occupancy, damage control, life safety, and collapse prevention (CP). Each level is associated with different levels of damage and corresponding degrees of functionality and safety. The fragility curves show that the building has a 50% chance of achieving or exceeding the (CP) level with highly intense ground vibrations with peak ground acceleration = 1.6 g. In addition, these curves can be beneficial in creating future local design codes and provide significant support in evaluating the seismic performance of existing buildings.
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Ciardo, D., P. Pisani, F. A. Lombardi, R. Franchini, F. Conversano e S. Casciaro. "POS0163 INCIDENT FRACTURE RISK PREDICTION USING THE FRAGILITY SCORE CALCULATED BY LUMBAR SPINE RADIOFREQUENCY ECHOGRAPHIC MULTI SPECTROMETRY (REMS) SCANS". Annals of the Rheumatic Diseases 80, Suppl 1 (19 maggio 2021): 294.2–294. http://dx.doi.org/10.1136/annrheumdis-2021-eular.2311.
Testo completoAbstract (sommario):
Background:The main consequence of osteoporosis is the occurrence of fractures due to bone fragility, with important sequelae in terms of disability and mortality. It has been already demonstrated that the information about bone mass density (BMD) alone is not sufficient to predict the risk of fragility fractures, since several fractures occur in patients with normal BMD [1].The Fragility Score is a parameter that allows to estimate skeletal fragility thanks to a trans-abdominal ultrasound scan performed with Radiofrequency Echographic Multi Spectrometry (REMS) technology. It is calculated by comparing the results of the spectral analysis of the patient’s raw ultrasound signals with reference models representative of fragile and non-fragile bones [2]. It is a dimensionless parameter, which can vary from 0 to 100, in proportion to the degree of fragility, independently from BMD.Objectives:This study aims to evaluate the effectiveness of Fragility Score, measured during a bone densitometry exam performed with REMS technology at lumbar spine, in identifying patients at risk of incident osteoporotic fractures at a follow-up period of 5 years.Methods:Caucasian women with age between 30 and 90 were scanned with spinal REMS and DXA. The incidence of osteoporotic fractures was assessed during a follow-up period of 5 years. The ability of the Fragility Score to discriminate between patients with and without incident fragility fractures was subsequently evaluated and compared with the discriminatory ability of the T-score calculated with DXA and with REMS.Results:Overall, 533 women (median age: 60 years; interquartile range [IQR]: 54-66 years) completed the follow-up (median 42 months; IQR: 35-56 months), during which 73 patients had sustained an incident fracture.Both median REMS and DXA measured T-score values were significantly lower in fractured patients than for non-fractured ones, conversely, REMS Fragility Score was significantly higher (Table 1).Table 1.Analysis of T-score values calculated with REMS and DXA and Fragility Score calculated with REMS. Median values and interquartile ranges (IQR) are reported. The p-value is derived from the Mann-Whitney test.Patients without incident fragility fracturePatients with incident fragility fracturep-valueT-score DXA[median (IQR)]-1.9 (-2.7 to -1.0)-2.6 (-3.3 to -1.7)0.0001T-score REMS[median (IQR)]-2.0 (-2.8 to -1.1)-2.7 (-3.5 to -1.9)<0.0001Fragility Score[median (IQR)]29.9 (25.7 to 36.2)53.0 (34.2 to 62.5)<0.0001By evaluating the capability to discriminate patients with/without fragility fractures, the Fragility Score obtained a value of the ROC area under the curve (AUC) of 0.80, higher than the AUC of the REMS T-score (0.66) and of the T-score DXA (0.64), and the difference was statistically significant (Figure 1).Figure 1.ROC curve comparison of Fragility Score, REMS and DXA T-score values in the classification of patients with incident fragility fractures.Furthermore, the correlation between the Fragility Score and the T-score values was low, with Pearson correlation coefficient r=-0.19 between Fragility Score and DXA T-score and -0.18 between the Fragility Score and the REMS T-score.Conclusion:The Fragility Score was found to be an effective tool for the prediction of fracture risk in a population of Caucasian women, with performances superior to those of the T-score values. Therefore, this tool presents a high potential as an effective diagnostic tool for the early identification and subsequent early treatment of bone fragility.References:[1]Diez Perez A et al. Aging Clin Exp Res 2019; 31(10):1375-1389.[2]Pisani P et al. Measurement 2017; 101:243–249.Disclosure of Interests:None declared
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Asadi, Payam, e Hosein Sourani. "Fragility curves production by seismic improvement of the high-dimensional model representation method". Engineering Computations 37, n. 1 (22 luglio 2019): 120–43. http://dx.doi.org/10.1108/ec-12-2018-0586.
Testo completoAbstract (sommario):
Purpose In the absence of random variables, random variables are generated by the Monte Carlo (MC) simulation method. There are some methods for generating fragility curves with fewer nonlinear analyses. However, the accuracy of these methods is not suitable for all performance levels and peak ground acceleration (PGA) range. This paper aims to present a method through the seismic improvement of the high-dimensional model representation method for generating fragility curves while taking advantage of fewer analyses by choosing the right border points. Design/methodology/approach In this method, the values of uncertain variables are selected based on the results of the initial analyses, the damage limit of each performance level or according to acceptable limits in the design code. In particular, PGAs are selected based on the general shape of the fragility curve for each performance limit. Also, polynomial response functions are estimated for each accelerogram. To evaluate the accuracy, fragility curves are estimated by different methods for a single degree of freedom system and a reinforced concrete frame. Findings The results indicated that the proposed method can not only reduce the computational cost but also has a higher accuracy than the other methods, compared with the MC baseline method. Originality/value The proposed response functions are more consistent with the actual values and are also congruent with each performance level to increase the accuracy of the fragility curves.
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Karimi-Moridani, K., P. Zarfam e M. Ghafory-Ashtiany. "Seismic Failure Probability of a Curved Bridge Based on Analytical and Neural Network Approaches". Shock and Vibration 2017 (2017): 1–18. http://dx.doi.org/10.1155/2017/2408234.
Testo completoAbstract (sommario):
This study focuses on seismic fragility assessment of horizontal curved bridge, which has been derived by neural network prediction. The objective is the optimization of structural responses of metaheuristic solutions. A regression model for the responses of the horizontal curved bridge with variable coefficients is built in the neural networks simulation environment based on the existing NTHA data. In order to achieve accurate results in a neural network, 1677 seismic analysis was performed in OpenSees. To achieve better performance of neural network and reduce the dimensionality of input data, dimensionality reduction techniques such as factor analysis approach were applied. Different types of neural network training algorithm were used and the best algorithm was adopted. The developed ANN approach is then used to verify the fragility curves of NTHA. The obtained results indicated that neural network approach could be used for predicting the seismic behavior of bridge elements and fragility, with enough feature extraction of ground motion records and response of structure according to the statistical works. Fragility curves extracted from the two approaches generally show proper compliance.
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Sonowal, D. B., e J. Pathak. "Seismic Fragility Analysis of an Existing Bridge Pier". Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, n. 1 (19 dicembre 2022): 789–92. http://dx.doi.org/10.38208/acp.v1.583.
Testo completoAbstract (sommario):
The main objective of this paper is to develop the fragility curves for an existing bridge having circular pier by static nonlinear analysis (Pushover Analysis). In this study, a cantilever circular bridge pier which is located in Assam, a highly seismic zone in India is considered for development of seismic fragility curve. Capacity of the bridge has been determined by Pushover analysis of bridge pier and demand parameter of the bridge were obtained by using ATC 40 Capacity Spectrum method and IS 1893:2016 (Part 1) along with IRC 6:2017. Civil Software SAP 2000 version 20 is used to analyze the bridge pier. The fragility curves of the pier have been constructed assuming a lognormal distribution. The evaluation results presented here describes the probabilistic seismic failure of the bridge pier and its capacity to meet the desired performance level.
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Favier, P., D. Bertrand, N. Eckert e M. Naaim. "A reliability assessment of physical vulnerability of reinforced concrete walls loaded by snow avalanches". Natural Hazards and Earth System Sciences 14, n. 3 (27 marzo 2014): 689–704. http://dx.doi.org/10.5194/nhess-14-689-2014.
Testo completoAbstract (sommario):
Abstract. Snow avalanches are a threat to many kinds of elements (human beings, communication axes, structures, etc.) in mountain regions. For risk evaluation, the vulnerability assessment of civil engineering structures such as buildings and dwellings exposed to avalanches still needs to be improved. This paper presents an approach to determine the fragility curves associated with reinforced concrete (RC) structures loaded by typical avalanche pressures and provides quantitative results for different geometrical configurations. First, several mechanical limit states of the RC wall are defined using classical engineering approaches (Eurocode 2), and the pressure of structure collapse is calculated from the usual yield line theory. Next, the fragility curve is evaluated as a function of avalanche loading using a Monte Carlo approach, and sensitivity studies (Sobol indices) are conducted to estimate the respective weight of the RC wall model inputs. Finally, fragility curves and relevant indicators such a their mean and fragility range are proposed for the different structure boundary conditions analyzed. The influence of the input distributions on the fragility curves is investigated. This shows the wider fragility range and/or the slight shift in the median that has to be considered when a possible slight change in mean/standard deviation/inter-variable correlation and/or the non-Gaussian nature of the input distributions is accounted for.
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Mirzaie Aminian, Farzad, Ehsan Khojastehfar e Hamid Ghanbari. "Effects of Near-fault Strong Ground Motions on Probabilistic Structural Seismic-induced Damages". Civil Engineering Journal 5, n. 4 (27 aprile 2019): 796–809. http://dx.doi.org/10.28991/cej-2019-03091289.
Testo completoAbstract (sommario):
Seismic fragility curves measure induced levels of structural damage against strong ground motions of earthquakes, probabilistically. These curves play an important role in seismic performance assessment, seismic risk analysis and making rational decisions regarding seismic risk management of structures. It has been demonstrated that the calculated fragility curves of structures are changed while the structures are excited by near-field strong ground motions in comparison with far-field ones. The objective of this paper is to evaluate the extents of modification for various performance levels and variety of structural heights. To achieve this goal, Incremental Dynamic Analysis (IDA) method is applied to calculate seismic fragility curves. To investigate the effects of earthquake characteristics, two categories of strong ground motions are assumed through IDA method, i.e. near and far-field sets. To study the extent of modification for various heights of structures, 4 – 6 and 10 stories moment-resisting concrete frames are considered as case studies. Furthermore, to study the importance of involving near-field strong ground motions in seismic performance assessment of structures, the damage levels are considered as the renowned structural performance levels (i.e. Immediate Occupancy, Life Safety, Collapse Prevention and Sidesway Collapse). Achieved results show that the fragility curve of low-rise frame (i.e. 4-story case study) for IO limit state presents more probability of damage applying near-fault sets in comparison with far-fault set. Investigating fragility curves of the other performance levels (i.e. LS, CP and Collapse) and the higher frames, a straightforward conclusion, regarding probability of damage. To achieve the rational results for the higher frames, mean annual frequency of exceedance (MAFE) and probability of exceeding limit states in 50 years are calculated. MAFE is defined as the integration of structural fragility curve over seismic hazard curve. According to the achieved results for 6-story frame, if the structure is excited by near-field strong ground motions the probability of exceedance for LS, CP and collapse limit states in 50 years will be increased up to 11%, 2.4%, 0.7% and 0.4% respectively, comparing with the calculated probabilities while far-field strong ground motions are applied. On the other hand, while the 10-story case study is excited by near-field strong ground motions, the exceedance probability values for mentioned limit states decreases up to 20%, 5%, 4% and 4%, respectively. Consequently, it can be concluded that the lower is the height of the structure, the more will be the increment of probability of damage in the near-field conditions. Furthermore, this increment is much more for IO limit state in comparison with other limit states. These facts can be applied as a precaution for seismic design of low-rise structures, while they are located at the vicinity of active faults.
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Yılmaz, Mehmet Fatih, Barlas Özden Çağlayan e Kadir Özakgül. "Seismic assessment of a curved multi-span simply supported truss steel railway bridge". Challenge Journal of Structural Mechanics 4, n. 1 (3 marzo 2018): 13. http://dx.doi.org/10.20528/cjsmec.2018.01.003.
Testo completoAbstract (sommario):
Fragility curve is an effective method to determine the seismic performance of a structural and nonstructural member. Fragility curves are derived for Highway Bridges for many studies. In Turkish railway lines, there are lots of historic bridges, and it is obvious that in order to sustain the safety of the railway lines, earthquake performance of these bridges needs to be determined. In this study, a multi-span steel truss railway bridge with a span length of 25.7m is considered. Main steel truss girders are supported on the abutments and 6 masonry piers. Also, the bridge has a 300m curve radius. Sap 2000 finite element software is used to model the 3D nonlinear modeling of the bridge. Finite element model is updating according to field test recordings. 60 real earthquake data selected from three different soil conditions are considered to determine the seismic performance of the bridge. Nonlinear time history analysis is conducted, and maximum displacements are recorded. Probabilistic seismic demand model (PSDMs) is used to determine the relationship between the Engineering Demand Parameter (EDP) and Intensity Measure (IMs). Fragility curve of the bridge is derived by considering the serviceability limit state, and results are discussed in detail.
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Shi, Zhaodong, Yan Liang, Yang Cao e Jialei Yan. "Time-Variant Seismic Fragility of Offshore Continuous Beam Bridges Based on Collapse Analysis". Applied Sciences 10, n. 23 (30 novembre 2020): 8595. http://dx.doi.org/10.3390/app10238595.
Testo completoAbstract (sommario):
In this paper, the concrete carbonation and chloride-induced corrosion of bridge structure in the service period under the offshore environment were comprehensively considered. Based on the time-varying degradation effect of mechanical properties of materials and continuous damage model, the time-varying seismic fragility of bridge components was analyzed with using incremental dynamic analysis. The time-varying brittleness curves of the bridge system and components were established according to the results of the analysis. According to the analysis of the time-varying fragility of the structure in the complete damage state, the collapse working conditions of the bridge structure and a method of quantifying the fragility coefficient were proposed. The results show that the fragility coefficient of the bridge system is higher than that of the components in the whole life cycle, and all of them increase with the increase of the bridge service cycle. When the peak acceleration of ground is small, the removing of 1# pier is more fragile. When reaching the design service life, the fragility coefficient of the bridge system is about 30% higher than that of the original state. The fragility coefficient of the bridge system in removing of 1# is the maximum value between three working conditions.
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McCrum, D. P., G. Amato e R. Suhail. "Development of Seismic Fragility Functions for a Moment Resisting Reinforced Concrete Framed Structure". Open Construction and Building Technology Journal 10, n. 1 (29 aprile 2016): 42–51. http://dx.doi.org/10.2174/1874836801610010042.
Testo completoAbstract (sommario):
Understanding the seismic vulnerability of building structures is important for seismic engineers, building owners, risk insurers and governments. Seismic vulnerability defines a buildings predisposition to be damaged as a result of an earthquake of a given severity. There are two components to seismic risk; the seismic hazard and the exposure of the structural inventory to any given earthquake event. This paper demonstrates the development of fragility curves at different damage states using a detailed mechanical model of a moment resisting reinforced concrete structure typical of Southern Europe. The mechanical model consists of a complex three-dimensional finite element model of the reinforced concrete moment resisting frame structure and is used to define the damage states through pushover analysis. Fragility curves are also defined using the HAZUS macro-seismic methodology and the Risk-UE macro-seismic methodology. Comparison of the mechanically modelled and HAZUS fragility curve shows good agreement while the Risk-UE methodology shows reasonably poor agreement.
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Ulza, Adrian, e Yunita Idris. "Earthquake vulnerability assessment of the 6.5 Mw Pidie Jaya earthquake: Analytical-based fragility curves". E3S Web of Conferences 340 (2022): 02008. http://dx.doi.org/10.1051/e3sconf/202234002008.
Testo completoAbstract (sommario):
Nearly all residential houses were damaged due to 6.5 Mw earthquake in Pidie Jaya, 2016. The state of damage can be slight, moderate, and even can be extensive which lead to the collapsing. The confined masonry structure, which commonly found in Aceh, especially for housing construction, were seemingly prone to the extensive earthquake excitation. In this paper, analytical-based fragility curves are employed to the typical house structure. To account various uncertainty, 32 ground motion records are considered in the analysis. Based on the results, the fragility curve could render different interpretation if different definition of damage intensities is used.
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Folić, Radomir, e Miloš Čokić. "Fragility and Vulnerability Analysis of an RC Building with the Application of Nonlinear Analysis". Buildings 11, n. 9 (1 settembre 2021): 390. http://dx.doi.org/10.3390/buildings11090390.
Testo completoAbstract (sommario):
In this paper, the seismic response of a five-story reinforced concrete (RC) frame system building is analysed through fragility analysis. The structure is designed in accordance with structural Eurocodes EN1990, EN1991, EN1992 and EN1998, as a high-ductility (DCH) system. For the analysis of the response of a structural system to earthquake actions, the methods of nonlinear static (NSA) and nonlinear dynamic analyses (NDA) are applied and, based on the obtained results, fragility curves are constructed using statistical methods. A relationship between the intensity measure (IM) and engineering demand parameters (EDPs) is needed in order to estimate a fragility curve. Fragility functions represent a possibility for different states of damage to occur in a certain structural systems at the observed value of the specified IM. Ten accelerograms, used in NDA, are selected and scaled, according to EN1998 provisions, for the chosen elastic response spectrum and referent PGA. Obtained results are used for the statistical analysis and construction of fragility curves. Structural damage state threshold parameters are determined based on the Park and Ang modified damage index methodology and provisions given in FEMA, HAZUS, VISION 2000 and EN codes. Comparative analysis of the structural damage probability for the analysed RC building, calculated using different methodologies to determine damage states, is applied. The fragility analysis results showed the difference between the probabilities of the damage states to occur when different calculation methods are used. This reflects on the assessment of vulnerability curves as well. The obtained results, calculated using different methods, are analysed using comparative analysis.
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Shinozuka, Masanobu, Maria Q. Feng, Ho-Kyung Kim e Sang-Hoon Kim. "Nonlinear Static Procedure for Fragility Curve Development". Journal of Engineering Mechanics 126, n. 12 (dicembre 2000): 1287–95. http://dx.doi.org/10.1061/(asce)0733-9399(2000)126:12(1287).
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Faghihmaleki, Hadi, Hamid Roosta, Ali Hooshmand Aini e Elmira Khaksar Najafi. "Using Fragility Curves for the Evaluation of Seismic Improvement of Steel Moment Frames". Afyon Kocatepe University Journal of Sciences and Engineering 16, n. 2 (1 giugno 2016): 323–37. http://dx.doi.org/10.5578/fmbd.26470.
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Dölen, Gül, e Mark F. Bear. "Courting a Cure for Fragile X". Neuron 45, n. 5 (marzo 2005): 642–44. http://dx.doi.org/10.1016/j.neuron.2005.02.021.
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Avşar, Özgür, Ahmet Yakut e Alp Caner. "Analytical Fragility Curves for Ordinary Highway Bridges in Turkey". Earthquake Spectra 27, n. 4 (novembre 2011): 971–96. http://dx.doi.org/10.1193/1.3651349.
Testo completoAbstract (sommario):
This study focuses on the development of analytical fragility curves for the ordinary highway bridges constructed after the 1990s. Four major bridge classes were employed based on skew angle, number of columns per bent, and span number (only multispan bridges). Nonlinear response-history analyses (NRHA) were conducted for each bridge sample using a detailed 3-D analytical model subjected to earthquake ground motions of varying seismic intensities. A component-based approach that uses several engineering demand parameters was employed to determine the seismic response of critical bridge components. Corresponding damage limit states were defined either in terms of member capacities or excessive bearing displacements. Lognormal fragility curves were obtained by curve fitting the point estimates of the probability of exceeding each specified damage limit state for each major bridge class. Bridges with larger skew angles or single-column bents were found to be the most seismically vulnerable.
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Nesrine, Guettafi, Yahiaoui Djarir, Abbeche Khelifa e Bouzid Tayeb. "Performance Assessment of Interaction Soil Pile Structure Using the Fragility Methodology". Civil Engineering Journal 7, n. 2 (1 febbraio 2021): 376–98. http://dx.doi.org/10.28991/cej-2021-03091660.
Testo completoAbstract (sommario):
This study aimed to investigate whether the seismic fragility and performance of interaction soil-pile-structure (ISPS) were affected by different parameters: axial load, a section of the pile, and the longitudinal steel ratio of the pile were implanted in different type of sand (loose, medium, dense). In order to better understand the ISPS phenomena, a series of nonlinear static analysis have been conducted for two different cases, namely: (i) fixed system and (ii) ISPS system, to get the curves of the capacity of every parameter for developing the fragility curve. After a comparison of the numerical results of pushover analysis and fragility curves, the results indicate that these parameters are significantly influenced on lateral capacity, ductility and seismic fragility on the ISPS. The increasing in the axial load exhibit high probabilities of exceeding the damage state. The increase in pile section and longitudinal steel ratio, the effect of probability damage (low and high) are not only related to the propriety geometrically, but also related to the values of ductility and lateral capacity of the system. Doi: 10.28991/cej-2021-03091660 Full Text: PDF
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Ghimire, Narayan, e Hemchandra Chaulagain. "Seismic Fragility Analysis of Institutional Building of Pokhara University". Himalayan Journal of Applied Science and Engineering 1, n. 1 (18 dicembre 2020): 31–39. http://dx.doi.org/10.3126/hijase.v1i1.33539.
Testo completoAbstract (sommario):
Fragility curves are derived from fragility function that indicates the probability of damage of structure due to earthquake as a function of ground motion parameter. It helps to predict the level of structural damage and consequently reduce the seismic risk in specific ground motion. In this scenario, this study is focused on the construction of fragility curve of institutional reinforced concrete (RC) building of Pokhara University. For this, the building of School of Health and Allied Science (SHAS) is considered as a guiding case study. For the numerical analysis, the study building blocks are modelled in finite element-based software. The non-linear static and linear dynamic analyses are employed for numerical analysis. In dynamic analysis, building models are subjected to the synthetic accelerograms of the 2015 Gorkha earthquake. Based on the analyses, the analytical fragility curves are plotted in terms of probability of failure at every 0.1 g interval of peak ground acceleration (PGA) with log normal distribution. Finally, the results are highlighted for different seismic performance level in buildings: slight damage, moderate damage, extensive damage and complete damage for the earthquake of 475 years return period.
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Handiana Devi, Rida, Senot Sangadji e Halwan Alfisa Saifullah. "Fragility curve of low-to-mid-rise concrete frame retrofitted with FRP". E3S Web of Conferences 156 (2020): 03006. http://dx.doi.org/10.1051/e3sconf/202015603006.
Testo completoAbstract (sommario):
In order to achieve satisfactory global seismic behaviour of a concrete fame structure and to prevent undesirable local failures of its structural element, local strengthening of structural members by means of FRP wrap is one of the cost effective retrofitting strategy. This FRP wrapped column will increase the ductility of the element as well as the capacity that in turn will allow attaining more energy dissipating global performance. This on-going research aims to demonstrate the seismic performance of Low-to-Mid-Rise Concrete Frame retrofitted by FRP wrap in several configurations. The fragility curves of the structure before and after to local strengthening will be developed and analysed. Fragility curve will describe the probability of the structure that will exceed certain damage states given the ground shaking intensity during its service life. This curve allows evaluation for the retrofitting strategy is carried out rationally.