scholarly journals Development of fragility curves for railway embankment and ballast scour due to overtopping flood flow

2016 ◽  
Vol 16 (12) ◽  
pp. 2455-2472 ◽  
Author(s):  
Ryota Tsubaki ◽  
Jeremy David Bricker ◽  
Koji Ichii ◽  
Yoshihisa Kawahara
Keyword(s):  
Spatial Distribution ◽  
Water Depth ◽  
Fragility Curves ◽  
Single Track ◽  
Damage Probability ◽  
Log Normal ◽  
Damage Type ◽  
Flood Flow

Abstract. Fragility curves evaluating a risk of railway embankment fill and track ballast scour were developed. To develop fragility curves, two well-documented events of single-track railway washout during floods in Japan were investigated. Type of damage to the railway was categorized into no damage, ballast scour, and embankment scour, in order of damage severity. Railway overtopping water depth for each event was estimated based on well-documented hydrologic and hydraulic analyses. Normal and log-normal fragility curves were developed based on damage probability derived from field records and the estimated overtopping water depth. A combined ballast and embankment scour model was validated by comparing the results of previous studies and the spatial distribution of railway damage type records.

scholarly journals Development of fragility curves for railway ballast and embankment scour due to overtopping flood flow

2016 ◽  
Author(s):  
Ryota Tsubaki ◽  
Koji Ichii ◽  
Jeremy D. Bricker ◽  
Yoshihisa Kawahara
Keyword(s):  
Spatial Distribution ◽  
Failure Probability ◽  
Fragility Curves ◽  
Railway Track ◽  
Single Track ◽  
Hydraulic Analysis ◽  
Railway Ballast ◽  
Log Normal ◽  
Flood Flow

Abstract. Fragility curves evaluating risk of railway track ballast and embankment fill scour were developed. To develop fragility curves, two well-documented single-track railway washouts during two recent floods in Japan were investigated. Type of damage to the railway was categorized into no damage, ballast scour, and embankment scour, in order of damage severity. Railway overtopping surcharge for each event was estimated via hydrologic and hydraulic analysis. Normal and log-normal fragility curves were developed based on failure probability derived from field records. A combined ballast and embankment scour model was validated by comparing the spatial distribution of railway scour with the field damage record.

scholarly journals Vulnerability Assessment of Buildings due to Land Subsidence Using InSAR Data in the Ancient Historical City of Pistoia (Italy)

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2749 ◽  
Author(s):  
Pablo Ezquerro ◽  
Matteo Del Soldato ◽  
Lorenzo Solari ◽  
Roberto Tomás ◽  
Federico Raspini ◽  
...  
Keyword(s):  
Fragility Curves ◽  
Central Italy ◽  
Sar Interferometry ◽  
Ground Subsidence ◽  
Public And Private ◽  
Radar Images ◽  
Spatial Deformation ◽  
Damage Probability ◽  
Medium Resolution ◽  
Vertical Displacements

The launch of the medium resolution Synthetic Aperture Radar (SAR) Sentinel-1 constellation in 2014 has allowed public and private organizations to introduce SAR interferometry (InSAR) products as a valuable option in their monitoring systems. The massive stacks of displacement data resulting from the processing of large C-B and radar images can be used to highlight temporal and spatial deformation anomalies, and their detailed analysis and postprocessing to generate operative products for final users. In this work, the wide-area mapping capability of Sentinel-1 was used in synergy with the COSMO-SkyMed high resolution SAR data to characterize ground subsidence affecting the urban fabric of the city of Pistoia (Tuscany Region, central Italy). Line of sight velocities were decomposed on vertical and E–W components, observing slight horizontal movements towards the center of the subsidence area. Vertical displacements and damage field surveys allowed for the calculation of the probability of damage depending on the displacement velocity by means of fragility curves. Finally, these data were translated to damage probability and potential loss maps. These products are useful for urban planning and geohazard management, focusing on the identification of the most hazardous areas on which to concentrate efforts and resources.

scholarly journals Seismic fragility curves based on the probability density evolution method

2017 ◽  
Vol 39 (2) ◽  
pp. 177-189
Author(s):  
Thuat-Cong Dang ◽  
Thien-Phu Le ◽  
Pascal Ray
Keyword(s):  
Probability Density ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Fragility Curve ◽  
Seismic Fragility ◽  
Cumulative Probability ◽  
Density Evolution ◽  
Probability Density Evolution Method ◽  
Log Normal ◽  
Probability Density Evolution

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.

A new methodological proposal for improving flood risk mapping using geostatistical techniques in Central-Western Spain

2021 ◽  
Author(s):  
Carolina Guardiola-Albert ◽  
Julio Garrote-Revilla ◽  
Miguel González-Jiménez ◽  
Andrés Díez-Herrero
Keyword(s):  
Spatial Distribution ◽  
Water Depth ◽  
Return Period ◽  
Flood Risk ◽  
Methodological Approach ◽  
Average Error ◽  
Hydrodynamic Modelling ◽  
River Channels ◽  
N Value ◽  
Channel Configuration

<p>The bathymetry of the riverbed is essential in flood risk assessment at large rivers, and yet its acquisition is a slow process and endowed with a high budget economic. Moreover, recent research works have shown the importance of improving the geometrical characterization inside the riverbed, which is an issue due to the inability of light to penetrate water bodies. So, most of LiDAR techniques allow us for high resolution surface topography data but not for water occupied river channels. This, apart from making these jobs more difficult, sometimes generates the renouncement of it, using the topography of the water sheet as a riverbed, or the simplification of river channel configuration (trapezoidal transversal sections) which frequently generate an overestimation of flood zones. To overcome these deficiencies, a novel methodological approach has been developed to simulate this bathymetry using simplified models. The proposed approach is based upon the calibration of the flow roughness parameters (Manning´s n value) inside the riverbed. The use of abnormally low Manning´s n values has made it possible to reproduce both the extent of the flooded area and the water depth value within it in an acceptable manner: first results from hydrodynamic modelling of 500-year return period peak flow show the reduction of the water depth average error from 50-75 cm to only about 10 cm; and a direct economic flood damage differences reduction from 25-30% to values of about 5%.</p><p>The present work proposes to go further with these investigations and perform a robust geostatistical analysis of hydrodynamic modelling outputs obtained with modified Manning’s n values. The methodology scheme is to characterize the spatial distribution of the results and its spatial correlation with other variables, as the distance to the riverbank or flow rates (for different return periods), through variogram models. This quantitative statistical description of the floodable areas, depending on the Manning’s n value model used and the return period considered, could be used to perform geostatistical simulations that allow to quantify the spatial uncertainties associated to the studied models; as well as to calibrate the optimal spatial distribution of modified Manning’s n values inside the riverbed. These findings will be analysed as guidelines to construct more robust and reliable flood risk estimations; and can be applied to many other study cases around the world, saving analysis time and execution costs, but without losing its scientific rigour.</p>

DISTRIBUIÇÃO ESPACIAL DA ÁGUA APLICADA POR EQUIPAMENTOS AUTOPROPELIDOS DE IRRIGAÇÃO - PARTE II: VALIDAÇÃO DO SIMULASOFT

Irriga ◽  
2010 ◽  
Vol 15 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Giuliani Do Prado ◽  
Alberto Colombo
Keyword(s):  
Spatial Distribution ◽  
Water Depth ◽  
Field Tests ◽  
Analytical Validation ◽  
Operational Conditions ◽  
Uniformity Coefficient ◽  
Average Value ◽  
Straight Line ◽  
Irrigation Uniformity ◽  
Application Profile

São apresentados resultados da validação analítica e experimental do aplicativo computacional SIMULASOFT, que simula a distribuição espacial da lâmina de água aplicada por equipamentos autopropelidos de irrigação. Para validação analítica, foram calculados valores de lâmina e uniformidade de aplicação de água, considerando-se um aspersor com perfil radial de formato triangular, em deslocamento linear com velocidade constante, operando com ângulos de giro de 270º e 360º. A comparação entre valores gerados analiticamente e pelo aplicativo demonstrou a equivalência dos dois processos. Valores de lâmina de água aplicados, observados em quatro ensaios de campo, realizados com um carretel enrolador dotado de um aspersor, da marca SIME®, modelo Big-River, quando comparados com valores produzidos pelo aplicativo, para as mesmas condições observadas nos ensaios de campo, apresentaram um coeficiente de determinação médio de 91,3%. Nas comparações entre os valores de coeficiente de uniformidade de Christiansen, simulados e observados em campo, verificou-se um erro relativo médio de 3,6%.   UNITERMOS: ensaios de uniformidade, simulação matemática, aspersores     PRADO, G. do; COLOMBO, A. SPATIAL DISTRIBUTION OF  WATER APPLIED BY TRAVELER iRRIGATIOn MACHINES - Part II: SIMULASOFT VALIDATION     2 ABSTRACT   Results from both analytical and experimental validation of Simulasoft, a software that simulates spatial distribution of  water applied by traveler irrigation machines, are presented. For the analytical validation, values of applied water depth and irrigation uniformity were input considering a sprinkler which presented radial water application profile and had triangular shape, moving along a straight line at constant speed and operating with wetted sectors of 270º and 360º. Comparisons among analytically input values and simulated ones have demonstrated that the two procedures are equivalent. When water depth values determined at four field tests of a traveler irrigation machine, set with a SIME® sprinkler, Big-River model, were compared to simulated values considering the operational conditions observed at field tests, a 91.3% determination coefficient was found. Comparisons among field observed and simulated Christiansen uniformity coefficient values showed that the relative error has a 3.6% average value. KEYWORDS: uniformity tests, irrigation uniformity, sprinklers  

Seismic Vulnerability of the Italian Roadway Bridge Stock

2015 ◽  
Vol 31 (4) ◽  
pp. 2137-2161 ◽  
Author(s):  
Barbara Borzi ◽  
Paola Ceresa ◽  
Paolo Franchin ◽  
Fabrizio Noto ◽  
Gian Michele Calvi ◽  
...  
Keyword(s):  
Seismic Vulnerability ◽  
State Of The Art ◽  
Fragility Curves ◽  
National Level ◽  
Civil Protection ◽  
Hazard Maps ◽  
The Core ◽  
Damage Probability ◽  
Level Of Knowledge ◽  
Existing Bridges

This study focuses on the evaluation of the seismic vulnerability of the Italian roadway bridge stock, within the framework of a Civil Protection sponsored project. A comprehensive database of existing bridges (17,000 bridges with different level of knowledge) was implemented. At the core of the study stands a procedure for automatically carrying out state-of-the-art analytical evaluation of fragility curves for two performance levels—damage and collapse—on an individual bridge basis. A WebGIS was developed to handle data and results. The main outputs are maps of bridge seismic risk (from the fragilities and the hazard maps) at the national level and real-time scenario damage-probability maps (from the fragilities and the scenario shake maps). In the latter case, the WebGIS also performs network analysis to identify routes to be followed by rescue teams. Consistency of the fragility derivation over the entire bridge stock is regarded as a major advantage of the adopted approach.

scholarly journals Characteristics of building fragility curves for seismic and non-seismic tsunamis: case studies of the 2018 Sunda Strait, 2018 Sulawesi-Palu and 2004 Indian Ocean tsunamis

2020 ◽  
Author(s):  
Elisa Lahcene ◽  
Ioanna Ioannou ◽  
Anawat Suppasri ◽  
Kwanchai Pakoksung ◽  
Ryan Paulik ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Fragility Curves ◽  
Building Damage ◽  
Wave Period ◽  
Cumulative Distribution ◽  
Flow Depth ◽  
Ground Shaking ◽  
Damage Probability ◽  
The Impact ◽  
Banda Aceh

Abstract. Indonesia has experienced several recent tsunamis triggered by seismic as well as non-seismic (i.e., landslides) sources. These events damaged or destroyed coastal buildings and infrastructure, and caused considerable loss of life. The impact of tsunami characteristics on structural components can be represented by fragility curves. These cumulative distribution functions express the likelihood of a structure reaching or exceeding a damage state in response to a tsunami hazard intensity measure. Using numerical simulations and post-tsunami observations, we successfully reproduce the hydrodynamic features of the 2018 Sunda Strait and 2018 Sulawesi-Palu tsunamis for the first time. We then compare non-seismic building fragility curves from these events with the ones of the 2004 Indian Ocean tsunami (IOT) to provide a novel understanding of wave period, ground shaking and liquefaction impacts on the structural performance of buildings. Below 5-m flow depth, the 2004 IOT in Khao Lak/Phuket (Thailand), characterized by long wave period due to its seismic source, induces larger damage to buildings than the 2018 Sunda Strait tsunami, triggered by a landslide. We also note that for 4-m flow depth, the building damage probability is almost twice less in Khao Lak/Phuket than in Banda Aceh, where ground motion has been reported before the tsunami arrival. In addition, liquefaction events can cause significant building damage as in Palu, where constructions have been considerably affected by this phenomenon due to the 2018 Sulawesi earthquake. Below 2-m flow depth, the damage probability is greater in Palu than in the Sunda Strait but also in Banda Aceh, although this city has been affected by ground shaking, and then struck by the longer wave period of the IOT.

scholarly journals A model for the spatial distribution of snow water equivalent parameterised from the spatial variability of precipitation

2016 ◽  
Author(s):  
Thomas Skaugen ◽  
Ingunn H. Weltzien
Keyword(s):  
Spatial Distribution ◽  
Spatial Variability ◽  
Snow Water Equivalent ◽  
Distribution Model ◽  
Snow Covered Area ◽  
Covered Area ◽  
Snow Water ◽  
Snow Distribution ◽  
Rainfall Runoff Model ◽  
Log Normal

Abstract. Snow is an important and complicated element in hydrological modelling. The traditional catchment hydrological model with its many free calibration parameters, also in snow sub-models, is not a well-suited tool for predicting conditions for which it has not been calibrated. Such conditions include prediction in ungauged basins and assessing hydrological effects of climate change. In this study, a new model for the spatial distribution of snow water equivalent (SWE), parameterized solely from observed spatial variability of precipitation (SD_G), is compared with the current snow distribution model used in the operational flood forecasting models in Norway. The latter model (SD_LN) has a fixed, calibrated coefficient of variation, which parameterizes a log-normal model for snow distribution. The two models are implemented in the already parameter parsimonious rainfall runoff model Distance Distribution Dynamics (DDD) and their capability for predicting runoff, SWE and snow covered area (SCA) are tested and compared for 71 Norwegian catchments. Results show that SD_G better simulates SCA when compared with MODIS satellite derived snow cover. In addition, SWE is simulated more realistically in that seasonal snow is melted out and the building up of "snow towers" and giving spurious positive trends in SWE, typical for SD_LN, is prevented. The precision of runoff simulations using SD_G is slightly inferior, with a reduction in Nash-Sutcliffe and Kling Gupta Criterion of 0.01, but it is shown that high precision in runoff prediction using SD_LN is accompanied with erroneous simulations of SWE.

scholarly journals Landslide-Induced Damage Probability Estimation Coupling InSAR and Field Survey Data by Fragility Curves

2019 ◽  
Vol 11 (12) ◽  
pp. 1486 ◽  
Author(s):  
Matteo Del Soldato ◽  
Lorenzo Solari ◽  
Francesco Poggi ◽  
Federico Raspini ◽  
Roberto Tomás ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Field Survey ◽  
Fragility Curves ◽  
Mitigation Strategies ◽  
Synthetic Aperture ◽  
Interferometric Synthetic Aperture Radar ◽  
Field Surveys ◽  
Damage Probability ◽  
Technological Advances ◽  
Aperture Radar

Landslides are considered to be one of the main natural geohazards causing relevant economic damages and social effects worldwide. Italy is one of the countries worldwide most affected by landslides; in the Region of Tuscany alone, more than 100,000 phenomena are known and mapped. The possibility to recognize, investigate, and monitor these phenomena play a key role to avoid further occurrences and consequences. The number of applications of Advanced Differential Interferometric Synthetic Aperture Radar (A-DInSAR) analysis for landslides monitoring and mapping greatly increased in the last decades thanks to the technological advances and the development of advanced processing algorithms. In this work, landslide-induced damage on structures recognized and classified by field survey and velocity of displacement re-projected along the steepest slope were combined in order to extract fragility curves for the hamlets of Patigno and Coloretta, in the Zeri municipality (Tuscany, northern Italy). Images using ERS1/2, ENVISAT, COSMO-SkyMed (CSK) and Sentinel-1 SAR (Synthetic Aperture Radar) were employed to investigate an approximate 25 years of deformation affecting both hamlets. Three field surveys were conducted for recognizing, identifying, and classifying the landslide-induced damage on structures and infrastructures. At the end, the damage probability maps were designed by means of the use of the fragility curves between Sentinel-1 velocities and recorded levels of damage. The results were conceived to be useful for the local authorities and civil protection authorities to improve the land managing and, more generally, for planning mitigation strategies.

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