Hazard Disaggregation and Record Selection for Fragility Analysis and Earthquake Loss Estimation

2017 ◽  
Vol 33 (2) ◽  
pp. 529-549 ◽  
Author(s):  
Luis Sousa ◽  
Mário Marques ◽  
Vitor Silva ◽  
Humberto Varum
Keyword(s):  
Ground Motion ◽  
Limit State ◽  
Fragility Analysis ◽  
Economic Losses ◽  
Earthquake Risk ◽  
Structural Class ◽  
Ground Motion Selection ◽  
Record Selection ◽  
Hazard Disaggregation ◽  
The Impact

Economic losses and collapse probability are critical measures for evaluating the earthquake risk of existing buildings. In this context, this study sheds light on several problems and limitations in current practice of hazard-consistent ground-motion selection and fragility analysis, focusing on the impact that (commonly assumed) approximations in disaggregation outputs have on the aforementioned risk metrics, as opposed to an exact solution. These issues are investigated for several building classes, seismicity models and ground motion prediction equations (GMPE), for a site in the city of Lisbon (Portugal). It is observed that only an exact (i.e., rupture-by-rupture) disaggregation can lead to satisfactory results in terms of accuracy, when limit state criteria are not structure-specific. On the other hand, an approximate method is proposed, which still leads to statistically valid results regardless of the chosen structural class, seismicity model or GMPE.

scholarly journals Dynamic Damage Mechanism and Seismic Fragility Analysis of an Aqueduct Structure

2021 ◽  
Vol 11 (24) ◽  
pp. 11709
Author(s):  
Xinyong Xu ◽  
Xuhui Liu ◽  
Li Jiang ◽  
Mohd Yawar Ali Khan
Keyword(s):  
Ground Motion ◽  
Structural Damage ◽  
Large Scale ◽  
Seismic Analysis ◽  
Fragility Curves ◽  
Limit State ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Exceedance Probability ◽  
Computation Efficiency

The Concrete Damaged Plasticity (CDP) constitutive is introduced to study the dynamic failure mechanism and the law of damage development to the aqueduct structure during the seismic duration using a large-scale aqueduct structure from the South-to-North Water Division Project (SNWDP) as a research object. Incremental dynamic analysis (IDA) and multiple stripe analysis (MSA) seismic fragility methods are introduced. The spectral acceleration is used as the scale of ground motion record intensity measure (IM), and the aqueduct pier top offset ratio quantifies the limit of structural damage measure (DM). The aqueduct structure’s seismic fragility evaluation curves are constructed with indicators of different seismic intensity measures to depict the damage characteristics of aqueduct structures under different seismic intensities through probability. The results show that penetrating damage is most likely to occur on both sides of the pier cap and around the pier shaft in the event of a rare earthquake, followed by the top of the aqueduct body, which requires the greatest care during an earthquake. The results of two fragility analysis methodologies reveal that the fragility curves are very similar. The aqueduct structure’s first limit state level (LS1) is quite steep and near the vertical line, indicating that maintaining the excellent condition without damage in the seismic analysis will be challenging. Except for individual results, the overall fragility results are in good agreement, and the curve change rule is the same. The exceedance probability in the case of any ground motion record IM may be estimated using only two factors when using the MSA approach, and the computation efficiency is higher. The study of seismic fragility analysis methods in this paper can provide a reference for the seismic safety evaluation of aqueducts and similar structures.

Correlation of Spectral Acceleration Values of Mainshock-Aftershock Ground Motion Pairs

2019 ◽  
Vol 35 (1) ◽  
pp. 39-60 ◽  
Author(s):  
Athanasios N. Papadopoulos ◽  
Mohsen Kohrangi ◽  
Paolo Bazzurro
Keyword(s):  
Ground Motion ◽  
Seismic Hazard Assessment ◽  
Statistical Correlation ◽  
Spectral Acceleration ◽  
Substantial Evidence ◽  
Period Range ◽  
Selection For ◽  
Spectral Accelerations ◽  
Record Selection ◽  
The Impact

This study examines the statistical correlation between the spectral accelerations of mainshock-aftershock ground motion pairs in the NGA-West2 ground motion database. Aftershock spectral accelerations are found mildly correlated with their mainshock counterparts for closely spaced periods of vibration and are weakly correlated over the rest of the period range. We further investigate for potential differences between the interperiod correlations of mainshock and aftershock spectral accelerations, finding no substantial evidence to support the use of different models for the two cases. Furthermore, the impact of different rupture scenario parameters on correlation is examined and discussed. The derived correlation estimates are expected to aid in aftershock seismic hazard assessment and/or in record selection for risk assessment applications by using the mainshock spectral ordinates to obtain better predictions for the aftershock ground motion.

Impact of partially non-ergodic site-specific probabilistic seismic hazard on risk assessment of single buildings

2020 ◽  
pp. 875529302093881
Author(s):  
Mohsen Kohrangi ◽  
Sreeram Reddy Kotha ◽  
Paolo Bazzurro
Keyword(s):  
Risk Assessment ◽  
Ground Motion ◽  
A Priori ◽  
Real Life ◽  
Site Specific ◽  
Risk Estimates ◽  
The Difference ◽  
Record Selection ◽  
Ground Motion Record Selection ◽  
The Impact

The growth of global ground-motion databases has allowed generation of non-ergodic ground-motion prediction equations (GMPEs) based on specific on-site recordings. Several studies have investigated the differences between the hazard estimates from ergodic versus non-ergodic GMPEs. Here instead we focus on the impact of non-ergodic PSHA estimates on the seismic risk of nonlinear single-degree-of-freedom systems representing ductile structures and compare it with the traditional risk estimates obtained using ergodic GMPEs. The structure-and-site-specific risk estimates depend not only on the difference in the hazard estimates but also on the different hazard-consistent ground-motion record selection that informs the response calculation. The more accurate structure-and-site-specific non-ergodic risk estimates show that traditional ones may be biased in a way impossible to predict a priori. Hence, the use of the non-ergodic approach is recommended, whenever possible. However, further advancements of non-ergodic GMPEs are necessary before being routinely utilized in real-life risk assessment applications.

scholarly journals Seismic Fragility Analysis of High Earth-Rockfill Dams considering the Number of Ground Motion Records

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Congcong Jin ◽  
Shichun Chi
Keyword(s):  
Ground Motion ◽  
Fragility Curves ◽  
Damage Index ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Settlement Rate ◽  
Earthquake Records ◽  
Rockfill Dam ◽  
Ground Motion Records ◽  
The Impact

This study analyzes the impact of the number of ground motions on the seismic fragility of a high earth-rockfill dam and the estimation of reasonable fragility parameters based on a sufficient number of earthquake records. In this paper, the vertical deformation is obtained using the three-dimensional finite element program DYNE3WAC combined with the Pastor–Zienkiewicz–Chan model and Biot dynamic consolidation theory. The relative seismic settlement rate is considered the damage index for the seismic fragility analysis of the dam. The fragility curves of the high earth-rockfill dam are determined by the multiple stripe analysis (MSA) method. A set of seismic waves is chosen based on the spectrum in the Chinese hydraulic structure seismic code. With an increasing number of earthquake records, the coefficients of variation (COV) of the mean and standard deviation (STD) of the relative seismic settlement rate decrease and tend to stabilize when the number of earthquake records reaches 34. The estimated fragility parameters θ and β are constant when the number of earthquake records exceeds 34. The requisite number of earthquake records for an accurate fragility estimation is determined by analyzing the lower and upper confidence intervals for the estimated θ and β. The 95% and 90% confidence interval can accurately estimate the fragility of a high earth-rockfill dam when the number of ground motion records reaches 36 and 32, respectively. The results of the fragility analysis demonstrate that the DYNE3WAC program and MSA method can provide an effective basis for determining fragility curves. Furthermore, the sensitivity analysis of earthquake records is essential for assessing the seismic fragility of high earth-rockfill dams.

On the Seismic Fragility Assessment of Concrete Gravity Dams in Eastern Canada

2019 ◽  
Vol 35 (1) ◽  
pp. 211-231 ◽  
Author(s):  
Rocio Segura ◽  
Carl Bernier ◽  
Ricardo Monteiro ◽  
Patrick Paultre
Keyword(s):  
Ground Motion ◽  
Fragility Curves ◽  
Limit State ◽  
Selection Method ◽  
Probabilistic Methods ◽  
Fragility Analysis ◽  
Gravity Dams ◽  
Limit States ◽  
Eastern Canada

In recent years, probabilistic methods, such as fragility analysis, have emerged as reliable tools for the seismic assessment of dam-type structures. These methods require the selection of a representative suite of ground motion records, resulting in the need for a ground motion selection method that includes all the relevant ground motion parameters in the fragility analysis of this type of structure. This article presents the development of up-to-date fragility curves for the sliding limit states of gravity dams in Eastern Canada using a record selection method based on the generalized conditional intensity measure approach. These fragility functions are then combined with the recently developed regional hazard data to evaluate the annual risk, which is measured in terms of the unconditional probability of limit state exceedance. The proposed methodology is applied to a case study dam in northeastern Canada, whose fragility is assessed through comparison with previous studies and current safety guidelines. It is observed that the more accurate procedure proposed herein produces less conservative fragility estimates for the case study dam.

scholarly journals Preliminary engineering analysis of the August 24th 2016, ML 6.0 central Italy earthquake records

2016 ◽  
Vol 59 ◽  
Author(s):  
Iunio Iervolino ◽  
Georgios Baltzopoulos ◽  
Eugenio Chioccarelli
Keyword(s):  
Ground Motion ◽  
Central Italy ◽  
Strong Motion ◽  
Response Spectra ◽  
Rupture Propagation ◽  
Return Periods ◽  
Central Italy Earthquake ◽  
Hazard Disaggregation ◽  
Directivity Effects ◽  
The Impact

An earthquake of estimated local magnitude (ML) 6.0 struck central Italy on the 24th of August (01:36:32 UTC) in the vicinity of Accumoli (close to Rieti, central Italy) initiating a long-lasting seismic sequence that also featured events of larger magnitude within a few months. The earthquake caused widespread building damage and around three-hundred fatalities. Ground motion was recorded by hundreds of seis-mic stations. This work uses accelerometric records for a preliminary discussion, from the earthquake en-gineering perspective, of strong motion caused by the earthquake. Peak and integral ground motion inten-sity measures, are presented. The response spectra at some select stations are analysed with respect to the code-mandated design actions for various return periods at the recording sites. Hazard disaggregation for different return periods is discussed referring to the site of the epicentre of the earthquake. Finally, some preliminary considerations are made concerning the impact of rupture propagation on near-source ground motion; i.e., the records are scanned for traces of pulse-like forward-directivity effects.

THE MAIN DIRECTIONS OF ECONOMIC SUPPORT OF THE REGIONAL SECURITY SYSTEM OF THE POPULATION

2020 ◽  
Vol 1 (11) ◽  
pp. 133-140
Author(s):  
E. V. DMITRIEVA ◽  
Keyword(s):  
Crisis Management ◽  
Security System ◽  
Regional Security ◽  
Economic Losses ◽  
Economic Damage ◽  
Economic Activities ◽  
The Sustainable Development ◽  
Economic Support ◽  
The Impact ◽  
Crisis Situations

The article considers topical issues of economic support for the development of the regional security system of the population against various risks. The dependence of the impact of the scale of crisis situations on economic activities in the constituent entities of the Russian Federation, which become a serious barrier to the sustainable development of the regions of the country, was investigated. The increasing importance of risks of economic losses from accidents and disasters at potentially dangerous facilities as a result of the complex influence of natural, manmade and fire factors has been established. An analysis was carried out and proposals were developed to implement the key tasks of the state in the field of ensuring the protection of the population and territories of the country from disasters in order to ensure the stability of the economy. The organizational structure, division of tasks and functions between officials, crisis management structures and responding units were analyzed, taking into account the reduction in current financial costs. On the basis of a study of the peculiarities of the regions of the country, recommendations were formed to fulfill the necessary tasks by the anti-crisis management bodies in the field of reducing economic damage on the basis of preventing crisis situations and ensuring fire safety. It is proposed to organize the practical application of a complex automated security system based on modern developments with the application of improving the qualities and efficiency of anti-crisis management processes in order to increase economic efficiency. Initial data were formed to reduce potential threats of a natural, man-made, fire and other nature in the regions using financial and economic mechanisms. It is proposed to implement a set of priority measures to further improve and increase the potential of economic support for the anti-crisis management system. The materials of the article can be used in planning the main directions of the development of the regional population security system and the implementation of socio-economic development programs.

Comparison of steel frames with RWS and WFP beam-to-column connections through seismic fragility analysis

2020 ◽  
pp. 136943322097728
Author(s):  
Haoran Yu ◽  
Weibin Li
Keyword(s):  
Limit State ◽  
Pushover Analysis ◽  
Steel Frames ◽  
Fragility Analysis ◽  
Structural Safety ◽  
Seismic Fragility ◽  
Fe Modelling ◽  
Collapse Resistance ◽  
Seismic Collapse ◽  
Probabilistic Seismic Demand

Reduced web section (RWS) connections and welded flange plate (WFP) connections can both effectively improve the seismic performance of a structure by moving plastic hinges to a predetermined location away from the column face. In this paper, two kinds of steel frames—with RWS connections and WFP connections—as well as different frames with welded unreinforced flange connections were studied through seismic fragility analysis. The numerical simulation was conducted by using multiscale FE modelling. Based on the incremental dynamic analysis and pushover analysis methods, probabilistic seismic demand analysis and seismic capability analysis were carried out, respectively. Finally, combined with the above analysis results, probabilistic seismic fragility analysis was conducted on the frame models. The results showed that the RWS connection and WFP connection (without double plates) have little influence on reducing the maximum inter-storey drift ratio under earthquake action. RWS connections slightly reduce the seismic capability in non-collapse stages and improve the seismic collapse resistance of a structure, which exhibits good structural ductility. WFP connections can comprehensively improve the seismic capability of a structure, but the seismic collapse resistance is worse than that of RWS connections when the structure has a large number of storeys. The frame with WFP connections has a lower failure probability at every seismic limit state, while the frame with RWS connections sacrifices some of its structural safety in non-collapse stages to reduce the collapse probability.

scholarly journals Modeling regional impacts and resilience to water service disruptions in urban economies

2021 ◽  
pp. 239980832199870
Author(s):  
Sheree A Pagsuyoin ◽  
Joost R Santos
Keyword(s):  
Case Studies ◽  
Large Scale ◽  
Urban Region ◽  
Economic Losses ◽  
Drought Severity ◽  
Severe Drought ◽  
Time Varying ◽  
National Capital Region ◽  
Economic Sectors ◽  
The Impact

Water is a critical natural resource that sustains the productivity of many economic sectors, whether directly or indirectly. Climate change alongside rapid growth and development are a threat to water sustainability and regional productivity. In this paper, we develop an extension to the economic input-output model to assess the impact of water supply disruptions to regional economies. The model utilizes the inoperability variable, which measures the extent to which an infrastructure system or economic sector is unable to deliver its intended output. While the inoperability concept has been utilized in previous applications, this paper offers extensions that capture the time-varying nature of inoperability as the sectors recover from a disruptive event, such as drought. The model extension is capable of inserting inoperability adjustments within the drought timeline to capture time-varying likelihoods and severities, as well as the dependencies of various economic sectors on water. The model was applied to case studies of severe drought in two regions: (1) the state of Massachusetts (MA) and (2) the US National Capital Region (NCR). These regions were selected to contrast drought resilience between a mixed urban–rural region (MA) and a highly urban region (NCR). These regions also have comparable overall gross domestic products despite significant differences in the distribution and share of the economic sectors comprising each region. The results of the case studies indicate that in both regions, the utility and real estate sectors suffer the largest economic loss; nonetheless, results also identify region-specific sectors that incur significant losses. For the NCR, three sectors in the top 10 ranking of highest economic losses are government-related, whereas in the MA, four sectors in the top 10 are manufacturing sectors. Furthermore, the accommodation sector has also been included in the NCR case intuitively because of the high concentration of museums and famous landmarks. In contrast, the Wholesale Trade sector was among the sectors with the highest economic losses in the MA case study because of its large geographic size conducive for warehouses used as nodes for large-scale supply chain networks. Future modeling extensions could potentially include analysis of water demand and supply management strategies that can enhance regional resilience against droughts. Other regional case studies can also be pursued in future efforts to analyze various categories of drought severity beyond the case studies featured in this paper.

scholarly journals Prevalence of mastitis in Nigerian livestock: a Review

2020 ◽  
Vol 1 (1) ◽  
pp. 20-29
Author(s):  
Hussaini Ojagefu Adamu ◽  
Rahimat Oshuwa Hussaini ◽  
Cedric Obasuyi ◽  
Linus Irefo Anagha ◽  
Gabriel Oscy Okoduwa
Keyword(s):  
Control Strategies ◽  
Dairy Farms ◽  
Livestock Production ◽  
Sub Saharan Africa ◽  
Economic Losses ◽  
Ecological Development ◽  
Management Plans ◽  
Sub Saharan ◽  
Control And Management ◽  
The Impact

AbstractMastitis is a disease of livestock that directly impede livestock production and thus hindering the socio-ecological development of sub-Saharan Africa. Studies have estimated the prevalence of this disease in 30% of Africa countries, with Ethiopia having the highest prevalence. The coverage is low, despite the wide livestock and dairy farms distribution in Africa. Furthermore, estimated economic losses due to the impact of mastitis are lacking in Nigeria. The disease is endemic in Nigeria as indicated by the available data and there are no proposed management plans or control strategies. This review is thus presented to serve as a wakeup call to all parties involved to intensify efforts towards the diagnosis, control, and management of the disease in Nigeria.

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