Engineering structures are often subjected to the influences of performance deterioration and multiple hazards during their service lives,and consequently may suffer from damage/failure as a result of external loads.S...Engineering structures are often subjected to the influences of performance deterioration and multiple hazards during their service lives,and consequently may suffer from damage/failure as a result of external loads.Structural reliability and resilience assessment is a powerful tool for quantifying the structural ability to withstand these environmental or operational attacks.This paper proposes new formulas for structural time-dependent reliability and resilience analyses in the presence of multiple hazards,which are functions of the duration of the reference period of interest.The joint impacts of nonstationarities in multiple hazards due to a changing environment,as well as the deterioration of structural performance,are explicitly incorporated.The correlation between the structural resistances/capacities associated with different hazard types is modeled by employing a copula function.It is observed that,under the context of multiple hazards and aging effects,the time-dependent resilience takes a generalized form of time-dependent reliability.The proposed formulas can be used to guide the adaptive design of structures,where adaptive strategies are identified across a range of possible future service conditions.An example is presented to demonstrate the applicability of the proposed method for structural reliability and resilience analyses.展开更多
Floods and earthquakes are the most common natural disasters,causing significant damage and casualties in urban communities.Although academic research has focused on assessing cities'ability to withstand these nat...Floods and earthquakes are the most common natural disasters,causing significant damage and casualties in urban communities.Although academic research has focused on assessing cities'ability to withstand these natural disasters,there is a lack of established frameworks for evaluating resilience against multiple hazards.This research integrates the earthquake and flood resilience indicators to create a comprehensive resilience assess-ment framework.This study integrated seismic and flood resilience indicators and categorized them into 27 clusters.It also used the DEMATEL(Decision-Making Trial and Evaluation Laboratory)method to determine the significance of clusters and prioritize them.This research identified 13 cause clusters and 14 effect clusters of indicators for seismic and flood resilience.The‘response capacity'cluster has the most impact on seismic and flood resilience,while the‘transportation and accessibility'cluster is the most affected cluster.This article presents a framework for evaluating flood and seismic resilience and makes suggestions for future research.展开更多
Coping with extreme climate events and its related climatic disasters caused by climate change has become a global issue and drew wide attention from scientists, policy-makers and public. This paper calculated the exp...Coping with extreme climate events and its related climatic disasters caused by climate change has become a global issue and drew wide attention from scientists, policy-makers and public. This paper calculated the expected annual multiple climatic hazards intensity index based on the results of nine climatic hazards including tropical cyclone, flood, landslide, storm surge, sand-dust storm, drought, heat wave, cold wave and wildfire. Then a vulnerability model involving the coping capacity indicator with mortality rate, affected population rate and GDP loss rate, was developed to estimate the expected annual affected population, mortality and GDP loss risks. The results showed that： countries with the highest risks are also the countries with large population or GDP. To substantially reduce the global total climatic hazards risks, these countries should reduce the exposure and improving the governance of integrated climatic risk; Without considering the total exposure, countries with the high mortality rate, affected population rate or GDP loss rate, which also have higher or lower coping capacity, such as the Philippines, Bangladesh and Vietnam, are the hotspots of the planning and strategy making for the climatic disaster risk reduction and should focus on promoting the coping capacity.展开更多
Water-related hazards, such as river floods, flash floods and droughts, are becoming more frequent in the Upper Chao Phraya River Basin, Thailand, due to climate change and urbanization, causing significant societal, ...Water-related hazards, such as river floods, flash floods and droughts, are becoming more frequent in the Upper Chao Phraya River Basin, Thailand, due to climate change and urbanization, causing significant societal, economic, and environmental damage. This study supports decision-making for nature-based solutions (NBS) to address mitigate these hazards. Using multi-criteria decision analysis, simulation modeling, and spatial analysis, the study identified precipitation and river discharges as key hazard drivers. Mapping hazard severity at various scales, the findings suggest that expanding green areas and water storage can enhance water management and reduce hazard impacts. This research offers critical insights for NBS adoption in water-related risk reduction.展开更多
The current AASHTO load and resistance factor design （LRFD） guidelines are formulated based on bridge reliability, which interprets traditional design safety factors into more rigorously deduced factors based on the...The current AASHTO load and resistance factor design （LRFD） guidelines are formulated based on bridge reliability, which interprets traditional design safety factors into more rigorously deduced factors based on the theory of probability. This is a major advancement in bridge design specifications. However, LRFD is only calibrated for dead and live loads. In cases when extreme loads are significant, they need to be individually assessed. Combining regular loads with extreme loads has been a major challenge, mainly because the extreme loads are time variables and cannot be directly combined with time invariant loads to formulate the probability of structural failure. To overcome these difficulties, this paper suggests a methodology of comprehensive reliability, by introducing the concept of partial failure probability to separate the loads so that each individual load combination under a certain condition can be approximated as time invariant. Based on these conditions, the extreme loads （also referred to as multiple hazard or MH loads） can be broken down into single effects. In Part II of this paper, a further breakdown of these conditional occurrence probabilities into pure conditions is discussed by using a live truck and earthquake loads on a bridge as an example. There are three major steps in establishing load factors from MH load distributions： （1） formulate the failure probabilities; （2） normalize various load distributions; and （3） establish design limit state equations. This paper describes the formulation of the failure probabilities of single and combined loads.展开更多
The current AASHTO load and resistance factor design （LRFD） guidelines are formulated based on bridge reliability, which interprets traditional design safety factors into more rigorously deduced factors based on the...The current AASHTO load and resistance factor design （LRFD） guidelines are formulated based on bridge reliability, which interprets traditional design safety factors into more rigorously deduced factors based on the theory of probability. This is a major advancement in bridge design specifications. However, LRFD is only calibrated for dead and live loads. In cases when extreme loads are significant, they need to be individually assessed. Combining regular loads with extreme loads has been a major challenge, mainly because the extreme loads are time variable and cannot be directly combined with time invariant loads to formulate the probability of structural failure.To overcome these difficulties, this paper suggests a methodology of comprehensive reliability, by introducing the concept of partial failure probability to separate the loads so that each individual load combination under a certain condition can be approximated a,; time invariant. Based on these conditions, the extreme loads （also referred to as multiple hazard or MH loads） can be broken down into single effects. In this paper, a further breakdown of these conditional occurrence probabilities into pure conditions is discussed by using a live truck and earthquake loads on a bridge as an example.展开更多
Public service facilities are fundamental to our society,and their disruption could amplify losses and cause cascading effects during natural disasters.However,there is little knowledge about the exposure of public se...Public service facilities are fundamental to our society,and their disruption could amplify losses and cause cascading effects during natural disasters.However,there is little knowledge about the exposure of public service facilities to natural disasters,and even less under the scenarios of multiple hazards.This study integrated big data of public service facilities into a multi-hazard exposure as-sessment of floods and earthquakes of China in 2021.Results show that public service facilities in China are disproportionally exposed to floods and earthquakes.Flood and seismic exposure reach 50.36%and 10.69%,which are 4.14 times and 1.05 times of the shares of the two hazard zones;in the overlapping zone 4.76%of the facilities are concentrated,5.17 times of the overlapping zone’s share.Par-ticularly,exposure of public service facilities is relatively high in Northwest China,where both the protection standards for floods and earthquakes are relatively weak.Furthermore,financial facilities contribute the most to flood exposure,while scientific and educational facilities contribute most to the overlapping exposure.We further propose location-specific optimization measures for different types of public service facilities.Our findings shed light on a comprehensive understanding and proper risk management of multi-hazard expos-ure of public service facilities.The incorporation of big data into multi-hazard exposure analysis of public service facilities can be exten-ded to various regions,thereby offering a valuable tool for informed management of natural disaster risk.展开更多
The perceived resilience of rural households has attracted considerable attention among both practitioners and researchers.However,a research gap still exists regarding its quantitative evaluation,place-based characte...The perceived resilience of rural households has attracted considerable attention among both practitioners and researchers.However,a research gap still exists regarding its quantitative evaluation,place-based characteristics,and impact mechanisms in areas threatened by multiple hazards.Based on data from 399 household questionnaire in typical villages of Wenchuan County,the epicenter of the Wenchuan earthquake on May 12,2008,a conceptual indicator framework of perceived resilience was established.Factor analysis was used to quantitatively evaluate the perceived resilience of rural households at different altitude gradient areas.A multiple linear regression model was used to describe the determinants of perceived resilience among different groups of households with disparate disaster experiences.The results show that:(1)A four-dimensional framework encompassing pre-disaster preventive capability,disaster coping capacity,post-disaster adaptive capacity,and learning and transition capability was identified by factor analysis for the quantitative measurement of the perceived resilience of rural households.(2)Their perceived resilience decreases with increasing altitude;the average perceived resilience score of households in the valley area is 1.5 times higher than that in the high mountains area.(3)Rural households with more experience of natural disasters exhibited higher levels of perceived resilience;however,this trend was reversed in the high mountains area.(4)The perceived resilience of households was significantly affected by most of the examined disaster preparedness indicators and a few of the examined personal characteristics indicators.For improving perceived resilience of rural households living in the study area,it is recommended to establish psychological crisis intervention networks in the valley area,promote more diversified livelihood strategies in the mid-mountains area,and mitigate the impacts of meteorological disasters in the high mountains area,respectively.展开更多
Recurrent events data and gap times between recurrent events are frequently encountered in many clinical and observational studies,and often more than one type of recurrent events is of interest.In this paper,we consi...Recurrent events data and gap times between recurrent events are frequently encountered in many clinical and observational studies,and often more than one type of recurrent events is of interest.In this paper,we consider a proportional hazards model for multiple type recurrent gap times data to assess the effect of covaxiates on the censored event processes of interest.An estimating equation approach is used to obtain the estimators of regression coefficients and baseline cumulative hazard functions.We examine asymptotic properties of the proposed estimators.Finite sample properties of these estimators are demonstrated by simulations.展开更多
Active control technology has been investigated and applied in numerous building structures and infrastructures since 1972 when it was firstly introduced into the civil engineering field by Professor JTP Yao.Now,half ...Active control technology has been investigated and applied in numerous building structures and infrastructures since 1972 when it was firstly introduced into the civil engineering field by Professor JTP Yao.Now,half a century has passed,a variety of control systems have been invented and implemented by researchers and engineers from all over the world.The recent years have witnessed remarkable research attempts and progress devoted to the development in this area based on modern control theory.However,there are still some unknown areas which are worthy of being explored in depth.One of such examples is the application of tuned mass dampers(TMD)to the flutter vibration control of long span bridges.Although applications of TMDs to bridges have been sighted in practice,their genuine effectiveness remains a serious question.The issues relating to how the coupled effect of TMD’s linear force being restricted by the rotational velocity of bridge’s deck during wind excitations which may eventually leads to flutter vibrations,remains unanswered.Such unusual phenomena and limitations were initially discovered and reported by the author sixteen years ago when investigating the barge ship crane hook’s swing motion control.In recent years,the author has invented the active rotary inertia driver(ARID)system which now has been granted patents in China,the US,Europe(including the UK,France,and Germany),Russia,Brazil,India,South Africa,Canada,Australia,Japan and Korean,etc.The ARID is an active control system which could exert direct control torque or moment to the target structures with rotational motions or vibrations natures,including and not limited to buildings,bridges or offshore platforms subjected to winds,earthquakes,and waves excitations.Furthermore,the ARID control system and its methodology can also be applicable to various mechanical systems including but not limited to cranes,vehicles,trains,ships,aircrafts,space crafts,satellites,and robotics.In this paper,the theory,modelling,comprehensive parametric analysis and case study of the ARID system for flutter vibration control of bridges will be discussed,as well as its promising applications in other various occasions.展开更多
基金supported by the Vice-Chancellor’s Postdoctoral Research Fellowship from the University of Wollongong.
文摘Engineering structures are often subjected to the influences of performance deterioration and multiple hazards during their service lives,and consequently may suffer from damage/failure as a result of external loads.Structural reliability and resilience assessment is a powerful tool for quantifying the structural ability to withstand these environmental or operational attacks.This paper proposes new formulas for structural time-dependent reliability and resilience analyses in the presence of multiple hazards,which are functions of the duration of the reference period of interest.The joint impacts of nonstationarities in multiple hazards due to a changing environment,as well as the deterioration of structural performance,are explicitly incorporated.The correlation between the structural resistances/capacities associated with different hazard types is modeled by employing a copula function.It is observed that,under the context of multiple hazards and aging effects,the time-dependent resilience takes a generalized form of time-dependent reliability.The proposed formulas can be used to guide the adaptive design of structures,where adaptive strategies are identified across a range of possible future service conditions.An example is presented to demonstrate the applicability of the proposed method for structural reliability and resilience analyses.
文摘Floods and earthquakes are the most common natural disasters,causing significant damage and casualties in urban communities.Although academic research has focused on assessing cities'ability to withstand these natural disasters,there is a lack of established frameworks for evaluating resilience against multiple hazards.This research integrates the earthquake and flood resilience indicators to create a comprehensive resilience assess-ment framework.This study integrated seismic and flood resilience indicators and categorized them into 27 clusters.It also used the DEMATEL(Decision-Making Trial and Evaluation Laboratory)method to determine the significance of clusters and prioritize them.This research identified 13 cause clusters and 14 effect clusters of indicators for seismic and flood resilience.The‘response capacity'cluster has the most impact on seismic and flood resilience,while the‘transportation and accessibility'cluster is the most affected cluster.This article presents a framework for evaluating flood and seismic resilience and makes suggestions for future research.
基金The Innovative Research Group Project of National Natural Science Foundation of China,No.41321001The National Basic Research Program(973 Program),No.2012CB955404The Program for Introducing Talents of Disciplines to Universities funded by the Ministry of Education and State Administration of Foreign Experts Affairs,China,No.B08008
文摘Coping with extreme climate events and its related climatic disasters caused by climate change has become a global issue and drew wide attention from scientists, policy-makers and public. This paper calculated the expected annual multiple climatic hazards intensity index based on the results of nine climatic hazards including tropical cyclone, flood, landslide, storm surge, sand-dust storm, drought, heat wave, cold wave and wildfire. Then a vulnerability model involving the coping capacity indicator with mortality rate, affected population rate and GDP loss rate, was developed to estimate the expected annual affected population, mortality and GDP loss risks. The results showed that： countries with the highest risks are also the countries with large population or GDP. To substantially reduce the global total climatic hazards risks, these countries should reduce the exposure and improving the governance of integrated climatic risk; Without considering the total exposure, countries with the high mortality rate, affected population rate or GDP loss rate, which also have higher or lower coping capacity, such as the Philippines, Bangladesh and Vietnam, are the hotspots of the planning and strategy making for the climatic disaster risk reduction and should focus on promoting the coping capacity.
文摘Water-related hazards, such as river floods, flash floods and droughts, are becoming more frequent in the Upper Chao Phraya River Basin, Thailand, due to climate change and urbanization, causing significant societal, economic, and environmental damage. This study supports decision-making for nature-based solutions (NBS) to address mitigate these hazards. Using multi-criteria decision analysis, simulation modeling, and spatial analysis, the study identified precipitation and river discharges as key hazard drivers. Mapping hazard severity at various scales, the findings suggest that expanding green areas and water storage can enhance water management and reduce hazard impacts. This research offers critical insights for NBS adoption in water-related risk reduction.
基金Federal Highway Administration at the University at Buffalo Under Contract Number DTFH61-08-C-00012
文摘The current AASHTO load and resistance factor design （LRFD） guidelines are formulated based on bridge reliability, which interprets traditional design safety factors into more rigorously deduced factors based on the theory of probability. This is a major advancement in bridge design specifications. However, LRFD is only calibrated for dead and live loads. In cases when extreme loads are significant, they need to be individually assessed. Combining regular loads with extreme loads has been a major challenge, mainly because the extreme loads are time variables and cannot be directly combined with time invariant loads to formulate the probability of structural failure. To overcome these difficulties, this paper suggests a methodology of comprehensive reliability, by introducing the concept of partial failure probability to separate the loads so that each individual load combination under a certain condition can be approximated as time invariant. Based on these conditions, the extreme loads （also referred to as multiple hazard or MH loads） can be broken down into single effects. In Part II of this paper, a further breakdown of these conditional occurrence probabilities into pure conditions is discussed by using a live truck and earthquake loads on a bridge as an example. There are three major steps in establishing load factors from MH load distributions： （1） formulate the failure probabilities; （2） normalize various load distributions; and （3） establish design limit state equations. This paper describes the formulation of the failure probabilities of single and combined loads.
基金Federal Highway Administration at the University at Buffalo Under Contract Number DTFH61-08-C-00012
文摘The current AASHTO load and resistance factor design （LRFD） guidelines are formulated based on bridge reliability, which interprets traditional design safety factors into more rigorously deduced factors based on the theory of probability. This is a major advancement in bridge design specifications. However, LRFD is only calibrated for dead and live loads. In cases when extreme loads are significant, they need to be individually assessed. Combining regular loads with extreme loads has been a major challenge, mainly because the extreme loads are time variable and cannot be directly combined with time invariant loads to formulate the probability of structural failure.To overcome these difficulties, this paper suggests a methodology of comprehensive reliability, by introducing the concept of partial failure probability to separate the loads so that each individual load combination under a certain condition can be approximated a,; time invariant. Based on these conditions, the extreme loads （also referred to as multiple hazard or MH loads） can be broken down into single effects. In this paper, a further breakdown of these conditional occurrence probabilities into pure conditions is discussed by using a live truck and earthquake loads on a bridge as an example.
基金Under the auspices of National Natural Science Foundation of China(No.41871200,4210010257)。
文摘Public service facilities are fundamental to our society,and their disruption could amplify losses and cause cascading effects during natural disasters.However,there is little knowledge about the exposure of public service facilities to natural disasters,and even less under the scenarios of multiple hazards.This study integrated big data of public service facilities into a multi-hazard exposure as-sessment of floods and earthquakes of China in 2021.Results show that public service facilities in China are disproportionally exposed to floods and earthquakes.Flood and seismic exposure reach 50.36%and 10.69%,which are 4.14 times and 1.05 times of the shares of the two hazard zones;in the overlapping zone 4.76%of the facilities are concentrated,5.17 times of the overlapping zone’s share.Par-ticularly,exposure of public service facilities is relatively high in Northwest China,where both the protection standards for floods and earthquakes are relatively weak.Furthermore,financial facilities contribute the most to flood exposure,while scientific and educational facilities contribute most to the overlapping exposure.We further propose location-specific optimization measures for different types of public service facilities.Our findings shed light on a comprehensive understanding and proper risk management of multi-hazard expos-ure of public service facilities.The incorporation of big data into multi-hazard exposure analysis of public service facilities can be exten-ded to various regions,thereby offering a valuable tool for informed management of natural disaster risk.
基金funded by the National Natural Science Foundation of China(grant number:42001244)Chengdu Science and Technology Program(grant number:2024-YF05-01061-SN)Research Program of Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(grant number:E4K2060060)。
文摘The perceived resilience of rural households has attracted considerable attention among both practitioners and researchers.However,a research gap still exists regarding its quantitative evaluation,place-based characteristics,and impact mechanisms in areas threatened by multiple hazards.Based on data from 399 household questionnaire in typical villages of Wenchuan County,the epicenter of the Wenchuan earthquake on May 12,2008,a conceptual indicator framework of perceived resilience was established.Factor analysis was used to quantitatively evaluate the perceived resilience of rural households at different altitude gradient areas.A multiple linear regression model was used to describe the determinants of perceived resilience among different groups of households with disparate disaster experiences.The results show that:(1)A four-dimensional framework encompassing pre-disaster preventive capability,disaster coping capacity,post-disaster adaptive capacity,and learning and transition capability was identified by factor analysis for the quantitative measurement of the perceived resilience of rural households.(2)Their perceived resilience decreases with increasing altitude;the average perceived resilience score of households in the valley area is 1.5 times higher than that in the high mountains area.(3)Rural households with more experience of natural disasters exhibited higher levels of perceived resilience;however,this trend was reversed in the high mountains area.(4)The perceived resilience of households was significantly affected by most of the examined disaster preparedness indicators and a few of the examined personal characteristics indicators.For improving perceived resilience of rural households living in the study area,it is recommended to establish psychological crisis intervention networks in the valley area,promote more diversified livelihood strategies in the mid-mountains area,and mitigate the impacts of meteorological disasters in the high mountains area,respectively.
基金supported in part by Natural Science Foundation of Hubei(08BA164)Major Research Program of Hubei Provincial Department of Education(09B2001)+2 种基金supported in part by National Natural Science Foundation of China(1117112)Doctoral Fund of Ministry of Education of China(20090076110001)National Statistical Science Research Major Program of China(2011LZ051)
文摘Recurrent events data and gap times between recurrent events are frequently encountered in many clinical and observational studies,and often more than one type of recurrent events is of interest.In this paper,we consider a proportional hazards model for multiple type recurrent gap times data to assess the effect of covaxiates on the censored event processes of interest.An estimating equation approach is used to obtain the estimators of regression coefficients and baseline cumulative hazard functions.We examine asymptotic properties of the proposed estimators.Finite sample properties of these estimators are demonstrated by simulations.
基金supported by the Ministry of Science and Technology of China (Grant No.2019YFE0112400)the Department of Science and Technology of Shandong Province (Grant No.2021CXGC011204)Liaoning Provincial Key Laboratory of Safety and Protection for Infrastructure Engineering。
文摘Active control technology has been investigated and applied in numerous building structures and infrastructures since 1972 when it was firstly introduced into the civil engineering field by Professor JTP Yao.Now,half a century has passed,a variety of control systems have been invented and implemented by researchers and engineers from all over the world.The recent years have witnessed remarkable research attempts and progress devoted to the development in this area based on modern control theory.However,there are still some unknown areas which are worthy of being explored in depth.One of such examples is the application of tuned mass dampers(TMD)to the flutter vibration control of long span bridges.Although applications of TMDs to bridges have been sighted in practice,their genuine effectiveness remains a serious question.The issues relating to how the coupled effect of TMD’s linear force being restricted by the rotational velocity of bridge’s deck during wind excitations which may eventually leads to flutter vibrations,remains unanswered.Such unusual phenomena and limitations were initially discovered and reported by the author sixteen years ago when investigating the barge ship crane hook’s swing motion control.In recent years,the author has invented the active rotary inertia driver(ARID)system which now has been granted patents in China,the US,Europe(including the UK,France,and Germany),Russia,Brazil,India,South Africa,Canada,Australia,Japan and Korean,etc.The ARID is an active control system which could exert direct control torque or moment to the target structures with rotational motions or vibrations natures,including and not limited to buildings,bridges or offshore platforms subjected to winds,earthquakes,and waves excitations.Furthermore,the ARID control system and its methodology can also be applicable to various mechanical systems including but not limited to cranes,vehicles,trains,ships,aircrafts,space crafts,satellites,and robotics.In this paper,the theory,modelling,comprehensive parametric analysis and case study of the ARID system for flutter vibration control of bridges will be discussed,as well as its promising applications in other various occasions.
