Lifelines, such as pipeline, transportation, communication, electric transmission and medical rescue systems, are complicated networks that always distribute spatially over large geological and geographic units. The q...Lifelines, such as pipeline, transportation, communication, electric transmission and medical rescue systems, are complicated networks that always distribute spatially over large geological and geographic units. The quantification of their reliability under an earthquake occurrence should be highly regarded, because the performance of these systems during a destructive earthquake is vital in order to estimate direct and indirect economic losses from lifeline failures, and is also related to laying out a rescue plan. The research in this paper aims to develop a new earthquake reliability calculation methodology for lifeline systems. The methodology of the network reliability for lifeline systems is based on fault tree analysis （FTA） and geological information system （GIS）. The interactions existing in a lifeline system ale considered herein. The lifeline systems are idealized as equivalent networks, consisting of nodes and links, and are described by network analysis in GIS. Firstly, the node is divided into two types： simple node and complicated node, where the reliability of the complicated node is calculated by FTA and interaction is regarded as one factor to affect performance of the nodes. The reliability of simple node and link is evaluated by code. Then, the reliability of the entilre network is assessed based on GIS and FTA. Lastly, an illustration is given to show the methodology.展开更多
The algorithm is based on constructing a disjoin kg t set of the minimal paths in a network system.In this paper, cubic notation was used to describe the logic function of a network in a well-balanced state,and then t...The algorithm is based on constructing a disjoin kg t set of the minimal paths in a network system.In this paper, cubic notation was used to describe the logic function of a network in a well-balanced state,and then the sharp-product operation was used to construct the disjoint minimal path set of the network.A computer program has been developed,and when combined with decomposition technology,the reliability of a general lifeline network can be effectively and automatically calculated.展开更多
In this paper, a new probabilistic analytical approach, the minimal cut-based recursive decomposition algorithm （MCRDA）, is presented to evaluate the seismic reliability of large-scale lifeline systems. Based on the...In this paper, a new probabilistic analytical approach, the minimal cut-based recursive decomposition algorithm （MCRDA）, is presented to evaluate the seismic reliability of large-scale lifeline systems. Based on the minimal cut searching algorithm, the approach calculates the disjoint minimal cuts one by one using the basic procedure of the recursive decomposition method. At the same time, the process obtains the disjoint minimal paths of the system. In order to improve the computation efficiency, probabilistic inequality is used to calculate a solution that satisfies the prescribed error bound. A series of case studies show that MCRDA converges rapidly when the edges of the systems have low reliabilities. Therefore, the approach can be used to evaluate large-scale lifeline systems subjected to strong seismic wave excitation.展开更多
The mechanism of lifeline system interaction is analyzed and the method and its corresponding result for categorizing the lifeline system in terms of interaction are presented. Various methods for the different kind o...The mechanism of lifeline system interaction is analyzed and the method and its corresponding result for categorizing the lifeline system in terms of interaction are presented. Various methods for the different kind of interaction are reviewed in this paper. For the function interaction of the lifeline system, an all-round study method is recommended. A WebGIS based aided decision-making method for the post-earthquake restoration of multi-lifeline system is also presented. Meanwhile, some key-points for lifeline system interaction are discussed.展开更多
Urban or regional disaster bearing capacity mainly depends on the disaster bearing capacity of lifeline systems. In the analysis of disaster bearing capacity evaluation of lifeline system, we should not only investiga...Urban or regional disaster bearing capacity mainly depends on the disaster bearing capacity of lifeline systems. In the analysis of disaster bearing capacity evaluation of lifeline system, we should not only investigate the complexity, balance and reliability of network characteristics, but also consider the relation between each subsystem. A new brittleness entropy of city disaster vulnerability associated coupling analysis method is proposed based on the brittleness of complex system theory. Correlation characteristics are reflected and evaluated in the brittle link entropy and the whole lifeline system, and then the vulnerability of city lifeline system can be quantified in flood scenarios. As a result of the coupling analysis and calculation, power system has the greatest effect among other subsystems. Because the key factors and influence of water supply system are uncertainties, the water supply system work or supply should be restored first after the disaster. The results show that the method can provide the basis for the optimization of system management, and control the repair work after disaster and coordination between subsystems.展开更多
The seismic reliability evaluation of lifeline networks has received considerable attention and been widely studied. In this paper, on the basis of an original recursive decomposition algorithm, an improved analytical...The seismic reliability evaluation of lifeline networks has received considerable attention and been widely studied. In this paper, on the basis of an original recursive decomposition algorithm, an improved analytical approach to evaluate the seismic reliability of large lifeline systems is presented. The proposed algorithm takes the shortest path from the source to the sink of a network as decomposition policy. Using the Boolean laws of set operation and the probabilistic operation principal, a recursive decomposition process is constructed in which the disjoint minimal path set and the disjoint minimal cut set are simultaneously enumerated. As the result, a probabilistic inequality can be used to provide results that satisfy a prescribed error bound. During the decomposition process, different from the original recursive decomposition algorithm which only removes edges to simplify the network, the proposed algorithm simplifies the network by merging nodes into sources and removing edges. As a result, the proposed algorithm can obtain simpler networks. Moreover, for a network owning s-independent components in its component set, two network reduction techniques are introduced to speed up the proposed algorithm. A series of case studies, including an actual water distribution network and a large urban gas system, are calculated using the proposed algorithm. The results indicate that the proposed algorithm provides a useful probabilistic analysis method for the seismic reliability evaluation of lifeline networks.展开更多
Underground lifeline engineering (ULE for short) in modern city demands the appreciation of an active fault in buried bedrock . Generally speaking , a large number of urban geological textures of a basement may all be...Underground lifeline engineering (ULE for short) in modern city demands the appreciation of an active fault in buried bedrock . Generally speaking , a large number of urban geological textures of a basement may all be simplified into a dual geological texture model , i. e., the upper part of the basement consists of loose covering layer and the lower part consists of bedrock . The study of an active fault should include three parts of contents , i . e ., to determine the lower time limit of activity of the fault , and the time limit must be recognized by both of designing engineers and geologists ; on the basis of the studies of repetition periods of earthquake occurrence to deter mine whether the fault moves or not during the allowed time of efficacy of buildings and constructions ; for the sake of engineering practice , the active rate of the fault must be given . The fault with different active mechanism has different effects on the ULE . The authors studied the effect of lateral non-uniform overburden site on the ULE by means of the supersonic earthquake modelling . Owing to the lateral non - uniformity of the covering sediments , there occurs an obvious jump of amplitude of the seismic wave propagation near the contact surface between two different sedi ments . In addition , from the modelling experiment curves it may be seen that the different focus mechanisms and different medium characters may also exert an effect in different degrees .展开更多
Suicide is one of the leading causes of teenagers＇ deaths. Even whether it is preventable, most of the time, there are still very few projects or actions of the local authorities and/or organisations in Romania, due ...Suicide is one of the leading causes of teenagers＇ deaths. Even whether it is preventable, most of the time, there are still very few projects or actions of the local authorities and/or organisations in Romania, due to the lack of information and resources. The suicide prevention line for children and teenagers in Bucharest is presented and evaluated after five years of activity. It may be considered as one example of good practice, since it managed to put together local knowledge, human resources, and social actors. The suicide prevention line for children and teenagers in Bucharest has been established in 2009 by the General Directorate of Social Welfare of Bucharest Municipality, in partnership with the Psychiatric Hospital ＂Prof. dr. Alexandru Obregia＂. The finances are provided by the Welfare Department, the location belongs to the Psychiatric Hospital, and the mental health services are coordinated by a neuro-psychiatrist. There are about 30 volunteers taking the phone calls 24/7. Since 2011, they established the Association of Suicidology.展开更多
reached a pivotal moment as the international community enters the final year of the UN Millennium Development Goals （MDGs）. The MDGs, agreed on by world leaders at a UN summit in 2000, set eight goals： poverty al...reached a pivotal moment as the international community enters the final year of the UN Millennium Development Goals （MDGs）. The MDGs, agreed on by world leaders at a UN summit in 2000, set eight goals： poverty alleviation.展开更多
The interconnection of urban critical infrastructure poses new challenges to the secure operation of power grid‐centric urban lifeline systems.The interdependencies among infrastructure systems increase the risk of c...The interconnection of urban critical infrastructure poses new challenges to the secure operation of power grid‐centric urban lifeline systems.The interdependencies among infrastructure systems increase the risk of cascading fault propagation,thereby threatening urban public safety.Coupling modelling and fault propagation simulation of urban lifeline systems provide a foundation for analysing disaster evolution mechanisms and support research on resilience assessment and enhancement technologies.In this paper,a coupling modelling and simulation method for urban lifeline systems under extreme disaster scenarios is proposed.First,based on fault propagation analysis requirements,the basic principles for coupling modelling are established,and simulation models suitable for lifeline systems under different time scales are analysed.Second,a co-simulation method combining time-driven and event-driven mechanisms is designed.Customised interfaces for information exchange between systems are developed based on mature simulation software,enabling the simulation of the disaster impact propagation process.Finally,the effectiveness of the proposed method is verified using a constructed urban lifeline coupling test system.展开更多
Research of reliability of engineering structures has experienced a developing history for more than 90 years.However,the problem of how to resolve the global reliability of structural systems still remains open,espec...Research of reliability of engineering structures has experienced a developing history for more than 90 years.However,the problem of how to resolve the global reliability of structural systems still remains open,especially the problem of the combinatorial explosion and the challenge of correlation between failure modes.Benefiting from the research of probability density evolution theory in recent years,the physics-based system reliability researches open a new way for bypassing this dilemma.The present paper introduces the theoretical foundation of probability density evolution method in view of a broad background,whereby a probability density evolution equation for probability dissipative system is deduced.In conjunction of physical equations and structural failure criteria,a general engineering reliability analysis frame is then presented.For illustrative purposes,several cases are studied which prove the value of the proposed engineering reliability analysis method.展开更多
They say you never miss the water until you see the well run dry.It’s certainly true in the case of the world’s endangered species.And especially in the instance of the South China tiger.By the time the conservation...They say you never miss the water until you see the well run dry.It’s certainly true in the case of the world’s endangered species.And especially in the instance of the South China tiger.By the time the conservation authorities hit the panic button it was already too late and the big beautiful cats had disappeared from the wilds of China,culled by hunters and poachers,and squeezed out of their habitat by the march of civilization and its voracious appetite for land. Now bred in captivity and rewilded,the tigers’numbers inch upwards.Growing public awareness helps. But replacing nature’s work artificially brings its own challenges.展开更多
Power supplies and telecommunications have been restored in much of the quake-hit region Communication and power supplies in most quake-hit areas in south- west China have been restored, said Xi Guohua,Vice Minister o...Power supplies and telecommunications have been restored in much of the quake-hit region Communication and power supplies in most quake-hit areas in south- west China have been restored, said Xi Guohua,Vice Minister of Industry and Information Technology,and Gu Junyuan,Chief Engineer of the State Electricity Regulatory Commission,at a press conference on May 19.展开更多
High-speed rails offer local economies along lines a chance to grow faster chenzhou, a medium-sized city in Hunan Province, knows what it’s like to be cut off from the rest of the world.
We live in an age where innovation has revolutionized almost every part of our lives. And the new and positive changes that innovation brings act as a catalyst that drives forward the development of our society.
This year marks the 100th anniversary of the birth of modern Chinese drama. For a century, after the efforts of generations of artists, local drama has grown to become an art form
This study describes a developing process of lifeline earthquake engineering from historical aspects.Currently various seismic design methods have been furnished for ground shaking and for permanent ground displacemen...This study describes a developing process of lifeline earthquake engineering from historical aspects.Currently various seismic design methods have been furnished for ground shaking and for permanent ground displacement.The seismic design method for ground shaking introduces different travelling wave models in the US and in Japan.As a result,Japanese approach was developed by actively taking into account the slippage effect in order to solve the inelastic response of the pipeline for a severe earthquake.The seismic design method for permanent ground displacement,on the other hand,prepared various numerical modeling and database in the US,while the simplified design formula for ground displacement was furnished in the seismic design guidelines in Japan.The detail design formula for liquefied ground settlement and fault displacement are expressed in this study.Various approaches of the performance-based seismic design method are compared among EU,the US and Japan.Unfortunately,the design method in Japan does not show the safety target in the guidelines.Then a simple evaluation approach to obtain the safety index is proposed herein.The different performance of two actual pipeline systems is compared,in which one pipeline system demonstrated a good performance for 2011 East Japan Great Earthquake,and the other did not.In state-of-the-art study,the seismic experiments and design method of expansion joints are described,because the ultimate limit performance of the expansion joints has not been explicit,although many seismic damages have occurred at the locations of vulnerable expansion joints.展开更多
To better understand the resilience evolution dynamics of urban lifeline systems over extended operational periods,this study introduces a model inspired by the susceptible-infected-recovered(SIR)model,which is tradit...To better understand the resilience evolution dynamics of urban lifeline systems over extended operational periods,this study introduces a model inspired by the susceptible-infected-recovered(SIR)model,which is traditionally used to simulate population health transitions.By analyzing the mechanisms governing the performance state evolution of urban lifeline systems under disaster scenarios,integrating a disaster scenario model with resilience assessment methodologies,and comprehensively considering three key resilience components—resistance,recovery,and adaptability—we develop a system dynamics resilience-reliability(SDR-R)model.A hypothetical case study is conducted to validate the model's applicability.The results indicate that the interplay of resistance,recovery,and adaptability influences the dynamic evolution of system performance across three states:disability performance,survivability performance,and recovery performance.The model reveals a cyclical pattern in resilience enhancement,with adaptability emerging as a critical determinant.Moreover,the SDR-R model not only simulates urban lifeline performance state evolution under single disaster scenarios but also captures resilience evolution trends over long-term system operations.The case study findings reveal that resilience decreases as disaster severity intensifies,yet positive feedback from adaptability fosters resilience improvement over time.The process of resilience evolution can be divided into four distinct phases:initial impact,adaptive priming,adaptive enhancement,and threshold effect.Notably,resilience dynamics vary significantly across disaster levels.While systems exhibit high resilience under low-level disasters,resilience gradually stabilizes at a high level in medium-and high-level disaster scenarios.However,extreme disasters introduce greater fluctuations in resilience,underscoring the necessity for targeted resilience-enhancing strategies.The insights derived from this study offer methodological guidance for understanding urban lifeline resilience evolution and developing strategies to enhance system robustness.展开更多
Underground utility tunnels are widely used in urban areas throughout the world for lifeline networks due to their easy maintenance and environmental protection capabilities. However, knowledge about their seismic per...Underground utility tunnels are widely used in urban areas throughout the world for lifeline networks due to their easy maintenance and environmental protection capabilities. However, knowledge about their seismic performance is still quite limited and seismic design procedures are not included in current design codes. This paper describes a series of shaking table tests the authors performed on a scaled utility tunnel model to explore its performance under earthquake excitation. Details of the experimental setup are first presented focusing on aspects such as the design of the soil container, scaled structural model, sensor array arrangement and test procedure. The main observations from the test program, including structural response, soil response, soil-structure interaction and earth pressure, are summarized and discussed. Further, a finite element model （FEM） of the test utility tunnel is established where the nonlinear soil properties are modeled by the Drucker- Prager constitutive model; the master-slave surface mechanism is employed to simulate the soil-structure dynamic interaction; and the confining effect of the laminar shear box to soil is considered by proper boundary modeling. The results from the numerical model are compared with experiment measurements in terms of displacement, acceleration and amplification factor of the structural model and the soil. The comparison shows that the numerical results match the experimental measurements quite well. The validated numerical model can be adopted for further analysis.展开更多
The concept of seismic resilience has received significant attention from academia and industry during the last two decades. Different frameworks have been proposed for seismic resilience assessment of engineering sys...The concept of seismic resilience has received significant attention from academia and industry during the last two decades. Different frameworks have been proposed for seismic resilience assessment of engineering systems at different scales(e.g., buildings, bridges, communities, and cities). Testbeds including Centerville virtual community(CVC), Memphis testbed(MTB), and the virtual city of Turin, Italy(VC-TI) have been developed during the last decade. However, the resilience assessment results of Chinese cities still require calibration based on a unified evaluation model. Therefore, a geographic information system(GIS)-based benchmark model of a medium-sized city located in the southeastern coastal region of China was developed. The benchmark city can be used to compare existing assessment frameworks and calibrate the assessment results. The demographics, site conditions, and potential hazard exposure of the benchmark city, as well as land use and building inventory are described in this paper. Data of lifeline systems are provided, including power, transportation, water, drainage, and natural gas distribution networks, as well as the locations of hospitals, emergency shelters, and schools. Data from past earthquakes and the literature were obtained to develop seismic fragility models, consequence models, and recovery models, which can be used as basic data or calibration data in the resilience assessment process. To demonstrate the completeness of the data included in the benchmark city, a case study on the accessibility of emergency rescue after earthquakes was conducted, and the preliminary results were discussed. The ultimate goal of this benchmark city is to provide a platform for calibrating resilience assessment results and to facilitate the development of resilient cities in China.展开更多
基金Sponsored by the Natural Science Foundation of China (Grant No.50278028) the Scientific Research Foundation of Harbin Institute of Technology(Grant No.HIT200079).
文摘Lifelines, such as pipeline, transportation, communication, electric transmission and medical rescue systems, are complicated networks that always distribute spatially over large geological and geographic units. The quantification of their reliability under an earthquake occurrence should be highly regarded, because the performance of these systems during a destructive earthquake is vital in order to estimate direct and indirect economic losses from lifeline failures, and is also related to laying out a rescue plan. The research in this paper aims to develop a new earthquake reliability calculation methodology for lifeline systems. The methodology of the network reliability for lifeline systems is based on fault tree analysis （FTA） and geological information system （GIS）. The interactions existing in a lifeline system ale considered herein. The lifeline systems are idealized as equivalent networks, consisting of nodes and links, and are described by network analysis in GIS. Firstly, the node is divided into two types： simple node and complicated node, where the reliability of the complicated node is calculated by FTA and interaction is regarded as one factor to affect performance of the nodes. The reliability of simple node and link is evaluated by code. Then, the reliability of the entilre network is assessed based on GIS and FTA. Lastly, an illustration is given to show the methodology.
基金Key Project of Science and Technology from the State Plan Committee.No.101-9914003
文摘The algorithm is based on constructing a disjoin kg t set of the minimal paths in a network system.In this paper, cubic notation was used to describe the logic function of a network in a well-balanced state,and then the sharp-product operation was used to construct the disjoint minimal path set of the network.A computer program has been developed,and when combined with decomposition technology,the reliability of a general lifeline network can be effectively and automatically calculated.
基金the Natural Science Fundation of China for the Innovative Research Group of China Under Grant No. 50621062
文摘In this paper, a new probabilistic analytical approach, the minimal cut-based recursive decomposition algorithm （MCRDA）, is presented to evaluate the seismic reliability of large-scale lifeline systems. Based on the minimal cut searching algorithm, the approach calculates the disjoint minimal cuts one by one using the basic procedure of the recursive decomposition method. At the same time, the process obtains the disjoint minimal paths of the system. In order to improve the computation efficiency, probabilistic inequality is used to calculate a solution that satisfies the prescribed error bound. A series of case studies show that MCRDA converges rapidly when the edges of the systems have low reliabilities. Therefore, the approach can be used to evaluate large-scale lifeline systems subjected to strong seismic wave excitation.
文摘The mechanism of lifeline system interaction is analyzed and the method and its corresponding result for categorizing the lifeline system in terms of interaction are presented. Various methods for the different kind of interaction are reviewed in this paper. For the function interaction of the lifeline system, an all-round study method is recommended. A WebGIS based aided decision-making method for the post-earthquake restoration of multi-lifeline system is also presented. Meanwhile, some key-points for lifeline system interaction are discussed.
文摘Urban or regional disaster bearing capacity mainly depends on the disaster bearing capacity of lifeline systems. In the analysis of disaster bearing capacity evaluation of lifeline system, we should not only investigate the complexity, balance and reliability of network characteristics, but also consider the relation between each subsystem. A new brittleness entropy of city disaster vulnerability associated coupling analysis method is proposed based on the brittleness of complex system theory. Correlation characteristics are reflected and evaluated in the brittle link entropy and the whole lifeline system, and then the vulnerability of city lifeline system can be quantified in flood scenarios. As a result of the coupling analysis and calculation, power system has the greatest effect among other subsystems. Because the key factors and influence of water supply system are uncertainties, the water supply system work or supply should be restored first after the disaster. The results show that the method can provide the basis for the optimization of system management, and control the repair work after disaster and coordination between subsystems.
基金Natural Science Funds for the Innovative Research Group of China Under Grant No.50621062
文摘The seismic reliability evaluation of lifeline networks has received considerable attention and been widely studied. In this paper, on the basis of an original recursive decomposition algorithm, an improved analytical approach to evaluate the seismic reliability of large lifeline systems is presented. The proposed algorithm takes the shortest path from the source to the sink of a network as decomposition policy. Using the Boolean laws of set operation and the probabilistic operation principal, a recursive decomposition process is constructed in which the disjoint minimal path set and the disjoint minimal cut set are simultaneously enumerated. As the result, a probabilistic inequality can be used to provide results that satisfy a prescribed error bound. During the decomposition process, different from the original recursive decomposition algorithm which only removes edges to simplify the network, the proposed algorithm simplifies the network by merging nodes into sources and removing edges. As a result, the proposed algorithm can obtain simpler networks. Moreover, for a network owning s-independent components in its component set, two network reduction techniques are introduced to speed up the proposed algorithm. A series of case studies, including an actual water distribution network and a large urban gas system, are calculated using the proposed algorithm. The results indicate that the proposed algorithm provides a useful probabilistic analysis method for the seismic reliability evaluation of lifeline networks.
基金The paper is one Part of a project supported by National Education Commitce Funds for Doctoral Faculty
文摘Underground lifeline engineering (ULE for short) in modern city demands the appreciation of an active fault in buried bedrock . Generally speaking , a large number of urban geological textures of a basement may all be simplified into a dual geological texture model , i. e., the upper part of the basement consists of loose covering layer and the lower part consists of bedrock . The study of an active fault should include three parts of contents , i . e ., to determine the lower time limit of activity of the fault , and the time limit must be recognized by both of designing engineers and geologists ; on the basis of the studies of repetition periods of earthquake occurrence to deter mine whether the fault moves or not during the allowed time of efficacy of buildings and constructions ; for the sake of engineering practice , the active rate of the fault must be given . The fault with different active mechanism has different effects on the ULE . The authors studied the effect of lateral non-uniform overburden site on the ULE by means of the supersonic earthquake modelling . Owing to the lateral non - uniformity of the covering sediments , there occurs an obvious jump of amplitude of the seismic wave propagation near the contact surface between two different sedi ments . In addition , from the modelling experiment curves it may be seen that the different focus mechanisms and different medium characters may also exert an effect in different degrees .
文摘Suicide is one of the leading causes of teenagers＇ deaths. Even whether it is preventable, most of the time, there are still very few projects or actions of the local authorities and/or organisations in Romania, due to the lack of information and resources. The suicide prevention line for children and teenagers in Bucharest is presented and evaluated after five years of activity. It may be considered as one example of good practice, since it managed to put together local knowledge, human resources, and social actors. The suicide prevention line for children and teenagers in Bucharest has been established in 2009 by the General Directorate of Social Welfare of Bucharest Municipality, in partnership with the Psychiatric Hospital ＂Prof. dr. Alexandru Obregia＂. The finances are provided by the Welfare Department, the location belongs to the Psychiatric Hospital, and the mental health services are coordinated by a neuro-psychiatrist. There are about 30 volunteers taking the phone calls 24/7. Since 2011, they established the Association of Suicidology.
文摘reached a pivotal moment as the international community enters the final year of the UN Millennium Development Goals （MDGs）. The MDGs, agreed on by world leaders at a UN summit in 2000, set eight goals： poverty alleviation.
基金supported by the National Key Research and Development Program of China,Grant:2022YFB2405500The Science and Technology Project of State Grid Corporation of China,Grant:52094023001HShanghai Electric Power Research Institute,State Grid Corporation of China,Grant:52094023003J.
文摘The interconnection of urban critical infrastructure poses new challenges to the secure operation of power grid‐centric urban lifeline systems.The interdependencies among infrastructure systems increase the risk of cascading fault propagation,thereby threatening urban public safety.Coupling modelling and fault propagation simulation of urban lifeline systems provide a foundation for analysing disaster evolution mechanisms and support research on resilience assessment and enhancement technologies.In this paper,a coupling modelling and simulation method for urban lifeline systems under extreme disaster scenarios is proposed.First,based on fault propagation analysis requirements,the basic principles for coupling modelling are established,and simulation models suitable for lifeline systems under different time scales are analysed.Second,a co-simulation method combining time-driven and event-driven mechanisms is designed.Customised interfaces for information exchange between systems are developed based on mature simulation software,enabling the simulation of the disaster impact propagation process.Finally,the effectiveness of the proposed method is verified using a constructed urban lifeline coupling test system.
文摘Research of reliability of engineering structures has experienced a developing history for more than 90 years.However,the problem of how to resolve the global reliability of structural systems still remains open,especially the problem of the combinatorial explosion and the challenge of correlation between failure modes.Benefiting from the research of probability density evolution theory in recent years,the physics-based system reliability researches open a new way for bypassing this dilemma.The present paper introduces the theoretical foundation of probability density evolution method in view of a broad background,whereby a probability density evolution equation for probability dissipative system is deduced.In conjunction of physical equations and structural failure criteria,a general engineering reliability analysis frame is then presented.For illustrative purposes,several cases are studied which prove the value of the proposed engineering reliability analysis method.
文摘They say you never miss the water until you see the well run dry.It’s certainly true in the case of the world’s endangered species.And especially in the instance of the South China tiger.By the time the conservation authorities hit the panic button it was already too late and the big beautiful cats had disappeared from the wilds of China,culled by hunters and poachers,and squeezed out of their habitat by the march of civilization and its voracious appetite for land. Now bred in captivity and rewilded,the tigers’numbers inch upwards.Growing public awareness helps. But replacing nature’s work artificially brings its own challenges.
文摘Power supplies and telecommunications have been restored in much of the quake-hit region Communication and power supplies in most quake-hit areas in south- west China have been restored, said Xi Guohua,Vice Minister of Industry and Information Technology,and Gu Junyuan,Chief Engineer of the State Electricity Regulatory Commission,at a press conference on May 19.
文摘High-speed rails offer local economies along lines a chance to grow faster chenzhou, a medium-sized city in Hunan Province, knows what it’s like to be cut off from the rest of the world.
文摘We live in an age where innovation has revolutionized almost every part of our lives. And the new and positive changes that innovation brings act as a catalyst that drives forward the development of our society.
文摘This year marks the 100th anniversary of the birth of modern Chinese drama. For a century, after the efforts of generations of artists, local drama has grown to become an art form
文摘This study describes a developing process of lifeline earthquake engineering from historical aspects.Currently various seismic design methods have been furnished for ground shaking and for permanent ground displacement.The seismic design method for ground shaking introduces different travelling wave models in the US and in Japan.As a result,Japanese approach was developed by actively taking into account the slippage effect in order to solve the inelastic response of the pipeline for a severe earthquake.The seismic design method for permanent ground displacement,on the other hand,prepared various numerical modeling and database in the US,while the simplified design formula for ground displacement was furnished in the seismic design guidelines in Japan.The detail design formula for liquefied ground settlement and fault displacement are expressed in this study.Various approaches of the performance-based seismic design method are compared among EU,the US and Japan.Unfortunately,the design method in Japan does not show the safety target in the guidelines.Then a simple evaluation approach to obtain the safety index is proposed herein.The different performance of two actual pipeline systems is compared,in which one pipeline system demonstrated a good performance for 2011 East Japan Great Earthquake,and the other did not.In state-of-the-art study,the seismic experiments and design method of expansion joints are described,because the ultimate limit performance of the expansion joints has not been explicit,although many seismic damages have occurred at the locations of vulnerable expansion joints.
基金supported by the Natural Science Research Project of the Anhui Educational Committee(Grant Number 2023AH051183)the Anhui Provincial Natural Science Foundation(Grant Number 2308085QG242)the National Natural Science Foundation of China(Grant Number 52404191).
文摘To better understand the resilience evolution dynamics of urban lifeline systems over extended operational periods,this study introduces a model inspired by the susceptible-infected-recovered(SIR)model,which is traditionally used to simulate population health transitions.By analyzing the mechanisms governing the performance state evolution of urban lifeline systems under disaster scenarios,integrating a disaster scenario model with resilience assessment methodologies,and comprehensively considering three key resilience components—resistance,recovery,and adaptability—we develop a system dynamics resilience-reliability(SDR-R)model.A hypothetical case study is conducted to validate the model's applicability.The results indicate that the interplay of resistance,recovery,and adaptability influences the dynamic evolution of system performance across three states:disability performance,survivability performance,and recovery performance.The model reveals a cyclical pattern in resilience enhancement,with adaptability emerging as a critical determinant.Moreover,the SDR-R model not only simulates urban lifeline performance state evolution under single disaster scenarios but also captures resilience evolution trends over long-term system operations.The case study findings reveal that resilience decreases as disaster severity intensifies,yet positive feedback from adaptability fosters resilience improvement over time.The process of resilience evolution can be divided into four distinct phases:initial impact,adaptive priming,adaptive enhancement,and threshold effect.Notably,resilience dynamics vary significantly across disaster levels.While systems exhibit high resilience under low-level disasters,resilience gradually stabilizes at a high level in medium-and high-level disaster scenarios.However,extreme disasters introduce greater fluctuations in resilience,underscoring the necessity for targeted resilience-enhancing strategies.The insights derived from this study offer methodological guidance for understanding urban lifeline resilience evolution and developing strategies to enhance system robustness.
基金Key Project in the National Science & Technology Pillar Program Under Grant No. 2006BAJ03B03Research Fund for Young Teacher Supported by State Key Laboratory for Disaster Reduction in Civil Engineering Under Grant No. SLDRCE08-C-03
文摘Underground utility tunnels are widely used in urban areas throughout the world for lifeline networks due to their easy maintenance and environmental protection capabilities. However, knowledge about their seismic performance is still quite limited and seismic design procedures are not included in current design codes. This paper describes a series of shaking table tests the authors performed on a scaled utility tunnel model to explore its performance under earthquake excitation. Details of the experimental setup are first presented focusing on aspects such as the design of the soil container, scaled structural model, sensor array arrangement and test procedure. The main observations from the test program, including structural response, soil response, soil-structure interaction and earth pressure, are summarized and discussed. Further, a finite element model （FEM） of the test utility tunnel is established where the nonlinear soil properties are modeled by the Drucker- Prager constitutive model; the master-slave surface mechanism is employed to simulate the soil-structure dynamic interaction; and the confining effect of the laminar shear box to soil is considered by proper boundary modeling. The results from the numerical model are compared with experiment measurements in terms of displacement, acceleration and amplification factor of the structural model and the soil. The comparison shows that the numerical results match the experimental measurements quite well. The validated numerical model can be adopted for further analysis.
基金Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration under Grant Nos. 2019EEEVL0505,2019B02 and 2019A02Heilongjiang Touyan Innovation Team Program。
文摘The concept of seismic resilience has received significant attention from academia and industry during the last two decades. Different frameworks have been proposed for seismic resilience assessment of engineering systems at different scales(e.g., buildings, bridges, communities, and cities). Testbeds including Centerville virtual community(CVC), Memphis testbed(MTB), and the virtual city of Turin, Italy(VC-TI) have been developed during the last decade. However, the resilience assessment results of Chinese cities still require calibration based on a unified evaluation model. Therefore, a geographic information system(GIS)-based benchmark model of a medium-sized city located in the southeastern coastal region of China was developed. The benchmark city can be used to compare existing assessment frameworks and calibrate the assessment results. The demographics, site conditions, and potential hazard exposure of the benchmark city, as well as land use and building inventory are described in this paper. Data of lifeline systems are provided, including power, transportation, water, drainage, and natural gas distribution networks, as well as the locations of hospitals, emergency shelters, and schools. Data from past earthquakes and the literature were obtained to develop seismic fragility models, consequence models, and recovery models, which can be used as basic data or calibration data in the resilience assessment process. To demonstrate the completeness of the data included in the benchmark city, a case study on the accessibility of emergency rescue after earthquakes was conducted, and the preliminary results were discussed. The ultimate goal of this benchmark city is to provide a platform for calibrating resilience assessment results and to facilitate the development of resilient cities in China.
