Mobile home fragility curves

2021 ◽  
pp. 875529302110575
Author(s):  
Bruce Maison ◽  
John Eidinger
Keyword(s):  
Peak Ground Acceleration ◽  
Fragility Curves ◽  
Seismic Fragility ◽  
Risk Modeling ◽  
Mobile Home ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Modeling Methodology ◽  
Manufactured Homes ◽  
Support Conditions

Seismic fragility of mobile (manufactured) homes is investigated. Compiled is a catalog of home performance in past earthquakes. Intensity measures causing damage are characterized by peak ground acceleration and velocity. Damage is defined as when the home is knocked out of position necessitating repairs and re-installation. Four categories of support conditions are identified: unanchored, tie-downs, proprietary systems, and perimeter wall foundations. Suggested fragility curves for unanchored homes and homes with tie-downs are derived from computer simulations. As a benchmark, a fragility curve for proprietary and perimeter wall systems is taken as the same as that for conventional wood homes. Shortcomings of using tie-down and proprietary systems in high seismic zones are discussed. The suggested fragility curves account for the different categories of support conditions thereby representing advancement to those in the Hazus national standardized risk modeling methodology.

scholarly journals Vertical Seismic Effect on the Seismic Fragility of Large-Space Underground Structures

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Zhiming He ◽  
Qingjun Chen
Keyword(s):  
Peak Ground Acceleration ◽  
Fragility Curves ◽  
Underground Structure ◽  
Seismic Effect ◽  
Peak Ground Velocity ◽  
Seismic Fragility ◽  
Vertical Acceleration ◽  
Underground Structures ◽  
Ground Acceleration ◽  
Large Space

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.

Seismic Fragility Analysis of Hill Buildings with Uneven Ground Column Heights

2014 ◽  
Vol 638-640 ◽  
pp. 1848-1853
Author(s):  
Lin Qing Huang ◽  
Li Ping Wang ◽  
Chao Lie Ning
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Slope Angle ◽  
Seismic Fragility ◽  
Exceedance Probability ◽  
Considerable Influence ◽  
Analysis Method ◽  
Ground Acceleration ◽  
Mountainous Regions ◽  
The Hill

The hill buildings sited on slopes have been widely constructed in mountainous regions. In order to estimate the seismic vulnerability of the hill buildings with uneven ground column heights under the effect of potential earthquakes, the exceedance probabilities of the hill buildings sited on different angle slopes in peak ground acceleration (PGA) are calculated and compared by using the incremental dynamic analysis method. The fragility curves show the slope angle has considerable influence on the seismic performance. Specifically, the exceedance probability increases with the increasing of the slope angle at the same performance level.

Seismic Hazard Analysis for an NPP Site

2004 ◽  
Author(s):  
A. K. Ghosh ◽  
H. S. Kushwaha
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Hazard Analysis ◽  
Structural Response ◽  
Response Spectra ◽  
Seismic Fragility ◽  
Material Strength ◽  
Ground Acceleration ◽  
Hazard Response

The various uncertainties and randomness associated with the occurrence of earthquakes and the consequences of their effects on the NPP components and structures call for a probabilistic seismic risk assessment (PSRA). However, traditionally, the seismic design basis ground motion has been specified by normalised response spectral shapes and peak ground acceleration (PGA). The mean recurrence interval (MRI) used to be computed for PGA only. The present work develops uniform hazard response spectra i.e. spectra having the same MRI at all frequencies for Kakrapar Atomic Power Station site. Sensitivity of the results to the changes in various parameters has also been presented. These results determine the seismic hazard at the given site and the associated uncertainties. The paper also presents some results of the seismic fragility for an existing containment structure. The various parameters that could affect the seismic structural response include material strength of concrete, structural damping available within the structure and the normalized ground motion response spectral shape. Based on this limited case study the seismic fragility of the structure is developed. The results are presented as families of conditional probability curves plotted against the peak ground acceleration (PGA). The procedure adopted incorporates the various randomness and uncertainty associated with the parameters under consideration.

scholarly journals The heuristic vulnerability model: fragility curves for masonry buildings

2021 ◽  
Author(s):  
Sergio Lagomarsino ◽  
Serena Cattari ◽  
Daria Ottonelli
Keyword(s):  
Large Scale ◽  
Fragility Curves ◽  
Expert Elicitation ◽  
Total Risk ◽  
Seismic Behaviour ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Bull Earthquake ◽  
Damage Scenarios ◽  
Vulnerability Model

AbstractIn the framework of seismic risk analyses at large scale, among the available methods for the vulnerability assessment the empirical and expert elicitation based ones still represent one of most widely used options. In fact, despite some drawbacks, they benefit of a direct correlation to the actual seismic behaviour of buildings and they are easy to handle also on huge stocks of buildings. Within this context, the paper illustrates a macroseismic vulnerability model for unreinforced masonry existing buildings that starts from the original proposal of Lagomarsino and Giovinazzi (Bull Earthquake Eng 4(4):445–463, 2006) and has further developed in recent years. The method may be classified as heuristic, in the sense that: (a) it is based on the expertise that is implicit in the European Macroseismic Scale (EMS98), with fuzzy assumptions on the binomial damage distribution; (b) it is calibrated on the observed damage in Italy, available in the database Da.D.O. developed by the Italian Department of Civil Protection (DPC). This approach guarantees a fairly well fitting with actual damage but, at the same time, ensures physically consistent results for both low and high values of the seismic intensity (for which observed data are incomplete or lacking). Moreover, the method provides a coherent distribution between the different damage levels. The valuable data in Da.D.O. allowed significant improvements of the method than its original version. The model has been recently applied in the context of ReLUIS project, funded by the DPC to support the development of Italian Risk Maps. To this aim, the vulnerability model has been applied for deriving fragility curves. This step requires to introduce a correlation law between the Macroseismic Intensity (adopted for the calibration of the model from a wide set of real damage data) and the Peak Ground Acceleration (at present, one of most used instrumental intensity measures); this conversion further increases the potential of the macroseismic method. As presented in the paper, the first applications of the model have produced plausible and consistent results at national scale, both in terms of damage scenarios and total risk (economic loss, consequences to people).

scholarly journals Seismic Fragility Analysis of Tunnels with Different Buried Depths in a Soft Soil

2020 ◽  
Vol 12 (3) ◽  
pp. 892
Author(s):  
Xiaorong Hu ◽  
Zhiguang Zhou ◽  
Hao Chen ◽  
Yongqiang Ren
Keyword(s):  
Structural Damage ◽  
Site Response ◽  
Seismic Station ◽  
Fragility Curves ◽  
Soft Soil ◽  
Limit State ◽  
Seismic Fragility ◽  
Evaluation Procedure ◽  
Ground Acceleration ◽  
Equivalent Linear

Seismic fragility of an engineering structure is the conditional probability that damage of a structure equals or exceeds a limit state under a specified intensity motion. It represents the seismic performance of structures and the correlation between ground motion and structural damage, playing an indispensable role in structural security assessment. A practical evaluation procedure of acquiring the fragility curves of tunnels in a soft soil has been proposed in this paper. Taking a typical metro tunnel in Shanghai as an example, two-dimensional finite element models of soil-tunnel cross-section were established. The nonlinear characteristics of soil layers were considered by the one-dimensional equivalent linear analysis in the equivalent-linear earthquake site response analyses (EERA) program. The ground motions were selected based on seismic station records. Comparing the analytical fragility curves with the empirical curves derived from American Lifelines Alliance (ALA) and HAZUS shows that the proposed method is reliable and feasible. Further study about the influence of buried depths on the fragility of the tunnel was performed. The results indicate that the failure probability of the tunnel is not monotonically decreasing with the increase of the buried depth for a given peak ground acceleration (PGA.)

scholarly journals Seismic Fragility Analysis of Poorly Built Timber Buildings in Yangon Slum Areas

2020 ◽  
Vol 15 (3) ◽  
pp. 407-415
Author(s):  
Khin Myat Kyaw ◽  
Chaitanya Krishna Gadagamma ◽  
Kyaw Kyaw ◽  
Hideomi Gokon ◽  
Osamu Murao ◽  
...  
Keyword(s):  
Fragility Curves ◽  
Load Test ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
State Matrix ◽  
Damage State ◽  
Ground Acceleration ◽  
Displacement Capacity ◽  
Pushover Curve ◽  
Slum Areas

In Yangon and the suburbs of Myanmar, timber-framed buildings are the popular choice of construction for residential purposes. Nearly 8% of the total population in Yangon live in the slums and slum-like areas where the dwellings are predominantly made of non-durable materials. Wood, jungle wood, and bamboo are used as the framework and corrugated galvanized iron sheets as walling and sheathing material. The seismic-resistance capacity of timber buildings in slum areas has never been approved based on experimental evidence. Therefore, this study aims to conduct a seismic fragility analysis for poorly built timber buildings by providing a suitable method through numerical and experimental approaches. Pull-over loading tests were conducted on selected buildings to assess their loading-displacement capacity. Further, numerical modeling was done using the Wallstat simulation tool, which is based on the discrete element method. The pushover curve was validated with the curve from the pull-over load test. Once the numerical model was confirmed, dynamic analysis was conducted for different peak ground acceleration (PGA) (g) values until the complete numerical collapse of the building. Three building configurations with three ranges of variable material properties were considered in this study. A primary damage state started at the low PGA value of 0.05 g, and it can be confirmed that the timber buildings that were studied, are vulnerable to earthquakes. The results based on qualitative analysis were accumulated to obtain the damage state matrix, which was then used to obtain the fragility curves.

Seismic Fragility Analysis of Hill Buildings Sited on Slopes

2014 ◽  
Vol 578-579 ◽  
pp. 1551-1555
Author(s):  
Li Ping Wang ◽  
Chao Lie Ning ◽  
Lin Qing Huang
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Incremental Dynamic Analysis ◽  
Seismic Fragility ◽  
Considerable Influence ◽  
Analysis Method ◽  
Probabilistic Characteristic ◽  
Ground Acceleration ◽  
Mountainous Regions ◽  
The Hill

The hill buildings sited on slopes has been widely constructed in mountainous regions. In order to estimate the seismic vulnerability for this type of building under the effect of potential earthquakes, the exceedance probabilities of hill buildings and normal buildings in peak ground acceleration are calculated and compared by using the incremental dynamic analysis method. The fragility curves show the layout of hill buildings has considerable influence on the seismic performance. Specifically, due to the different layout for the hill buildings, the probabilistic characteristic at the collapse prevention level is significantly different from the characteristic of fragility curves at the initial performance level.

Observational Seismic Fragility Curves for Steel Cylindrical Tanks

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Marta D'Amico ◽  
Nicola Buratti
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Bayesian Regression ◽  
Industrial Safety ◽  
Seismic Fragility ◽  
Storage Tanks ◽  
Ground Acceleration ◽  
Technical Literature ◽  
Cylindrical Tanks ◽  
Extent Of Damage

The evaluation of seismic vulnerability of atmospheric above ground steel storage tanks is a fundamental topic in the context of industrial safety. Depending on the shell portion affected, on the extent of damage, and on toxicity, flammability, and reactivity of stored substances, liquid leakages can trigger hazardous chains of events whose consequences affect not only the plant but also the surrounding environment. In light of that, the study proposed herein provides an analysis of the seismic fragility of cylindrical above ground storage tanks based on observational damage data. The first phase of this work has consisted in collecting a large empirical dataset of information on failures of atmospheric tanks during past earthquakes. Two sets of damage states have then been used in order to characterize the severity of damage and the intensity of liquid releases. Empirical fragility curves have been fitted by using Bayesian regression. The advantage of this approach is that it is well suited to treat direct and indirect information obtained from field observations and to incorporate subjective engineering judgement. Different models have been employed in order to investigate the effects of tank aspect ratio, filling level, and base anchorage. Moreover, the effects of interaction between these critical aspects are included in fragility analysis. The hazard parameter used is the peak ground acceleration (PGA). Seismic fragility curves obtained from the described procedure are compared to those available in the technical literature.

scholarly journals Typological Damage Fragility Curves for Unreinforced Masonry Buildings affected by the 2009 L'Aquila, Italy Earthquake

2021 ◽  
Vol 15 (1) ◽  
pp. 117-134
Author(s):  
Maria Zucconi ◽  
Rachele Ferlito ◽  
Luigi Sorrentino
Keyword(s):  
Peak Ground Acceleration ◽  
Risk Mitigation ◽  
Fragility Curves ◽  
Relative Size ◽  
Unreinforced Masonry ◽  
Building Damage ◽  
Economic Losses ◽  
Structural Elements ◽  
Damage State ◽  
Ground Acceleration

Background: Seismic risk mitigation has become a crucial issue due to the great number of casualties and large economic losses registered after recent earthquakes. In particular, unreinforced masonry constructions built before modern seismic codes, common in Italy and in other seismic-prone areas, are characterized by great vulnerability. In order to implement mitigation policies, analytical tools are necessary to generate scenario simulations. Methods: Therefore, data collected during inspections after the 2009 L’Aquila, Italy earthquake are used to derive novel fragility functions. Compared to previous studies, data are interpreted accounting for the presence of buildings not inspected due to those being undamaged. An innovative building damage state is proposed and is based on the response of different structural elements recorded in the survey form: vertical structures, horizontal structures, stairs, roof, and partition walls. In the suggested formulation, the combination of their performance is weighted based on typical reparation techniques and on the relative size of the structural elements, estimated from a database of complete geometrical surveys developed specifically for this study. Moreover, the proposed building damage state estimates earthquake-related damage by removing the preexisting damage reported in the inspection form. Results: Lognormal fragility curves, in terms of building damage state grade as a function of typological classes and peak ground acceleration, derived maximizing their likelihood and their merits compared with previous studies are highlighted. Conclusion: The correction of the database to account for uninspected buildings delivers curves that are less “stiff” and reach the median for lower peak ground acceleration values. The building feature that influences most the fragility is the masonry quality.

Seismic Fragility Study for High-Pressure Emergency Cooling Water Tanks of Loviisa Nuclear Power Plant

2010 ◽  
Author(s):  
Jukka Ka¨hko¨nen ◽  
Pentti Varpasuo
Keyword(s):  
High Pressure ◽  
Standard Deviation ◽  
Power Plant ◽  
Peak Ground Acceleration ◽  
Nuclear Power ◽  
Cooling Water ◽  
Seismic Fragility ◽  
Ground Acceleration ◽  
Time Histories ◽  
Water Tanks

The paper studies the fragility of high-pressure emergency cooling water tanks in Loviisa Nuclear Power Plant located on the elevation +25.40 in the reactor building. The seismic fragility is defined as the conditional probability of its failure given a value of the response parameter, such as peak ground acceleration. Using the lognormal-distribution assumption, the fragility (i.e., the probability of failure, f′) at any non-exceedance probability level Q can be derived as Equation1f′=Φ[(ln(a/A¯)+βUΦ−1(Q))/βR] where Q = P(f<f′|a) is the probability that the conditional probability f is less than f′ for a peak ground acceleration a. A is the median ground acceleration capacity, βR is the logarithmic standard deviation representing the randomness about A, and βU is the logarithmic standard deviation representing the uncertainty. The quantity Φ(.) is the standard Gaussian cumulative distribution function. In order to assess the fragility of the tanks the strain time histories for tank supports and piping nozzles were calculated using the joint structural-equipment model. The ground motion response spectra shape used in the structural response analysis has been taken from the YVL 2.6 – guide [1]. This shape represents the envelope spectrum for Southern Finland corresponding to the median annual frequency of 10−5. The sampling of the model properties was carried out with the aid of the Latin hypercube sampling method. In order to find the failure modes the strain time histories were calculated for the piping nozzles and for support structures of the tanks. Since strain is the best measure of energy absorption, energy limited events need to be based on the strain acceptance criteria. The adopted failure limit is the cumulated plastic strain of 8% in the tank sheet metal or in the supporting structures. This failure limit has taken from the reference [2]. The end result of the study is the presentation of the median fragility curve for the tanks as well as 95% and 5% fractile curves.

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