Current building design codes allow the appearance of structural and nonstructural damage under design basis earthquakes.The research regarding probabilistic seismic loss estimation in domestic building structure is u...Current building design codes allow the appearance of structural and nonstructural damage under design basis earthquakes.The research regarding probabilistic seismic loss estimation in domestic building structure is urgent.The evaluation in this paper is based on a 11-story reinforced concrete office building,incremental dynamic analysis(IDA)is conducted in Perform 3D program using models capable to simulate all possible limit states up to collapse.Next,the probability distribution of post-earthquake casualties,rebuild costs repair costs and business downtime loss are calculated in PACT software for the studied building considering the modified component vulnerability groups and population flow models.The evaluation procedure can also shed light on other types of buildings in China.For non-typical functional building structures,this article proposes to build a finite element model of structural components and to classify the vulnerability groups based on the construction drawings,and to supply and improve the vulnerability library of appendages in FEMA P-58 according to the actual situation.In this way,the application scope of building seismic performance evaluation can be expanded.展开更多
The depth and breadth of participation in the global value chain(GVC)significantly impacts a country's fine particulate contamination(PM_(2.5))emissions.First,based on the GVC accounting framework,the sources of P...The depth and breadth of participation in the global value chain(GVC)significantly impacts a country's fine particulate contamination(PM_(2.5))emissions.First,based on the GVC accounting framework,the sources of PM_(2.5) emissions in China between 1990 and 2015 are identified and investigated considering production-side,consumption-side,and export-implied pollution.Then,index decomposition analysis(IDA)of emissions is conducted to further investigate the changes in and causes of air pollution in China.Throughout the analytical process,differences between the PM_(2.5) emissions in two time periods-one of rapid economic growth and another of the“new normal”economy-are compared.The results demonstrate that:China is embedded in high pollution links of GVCs;China transfers pollution to third-parties by importing intermediate products from resource-intensive countries in the global production system;extensive economic growth caused an increase in China's total PM_(2.5) emissions,but cleaner production technology can reduce the emissions intensity.Industrial restructuring under the“new normal”has increased China's short-term PM_(2.5) emissions intensity.These results suggest that China should optimize and upgrade its domestic economic structure and transform its export growth mode to deliver high added value and low pollution.Further,it should prioritize cooperation between the upstream and downstream value chain and accelerate the upgrading of its consumption structure in this new era.展开更多
Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be...Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be expressed either as a likelihood of damage or potential financial loss.Engineers tend to make use of the former(i.e.damage).Nevertheless,other non-technical stakeholders cannot get useful information from damage.However,if financial risk is expressed on the basis of probable monetary loss,it will be easily understood by all.Therefore,it is necessary to develop methodologies which communicate the system capacity and demand to financial risk,Incremental dynamic analysis(IDA) was applied in a performance-based earthquake engineering context to do hazard analysis,structural analysis,damage analysis and loss analysis of a reinforced concrete(RC) frame structure.And the financial implications of risk were expressed by expected annual loss(EAL).The quantitative risk analysis proposed is applicable to any engineering facilities and any natural hazards.It is shown that the results from the IDA can be used to assess the overall financial risk exposure to earthquake hazard for a given constructed facility.The computational IDA-EAL method will enable engineers to take into account the long-term financial implications in addition to the construction cost.Consequently,it will help stakeholders make decisions.展开更多
A novel face recognition method, which is a fusion of muhi-modal face parts based on Gabor feature （MMP-GF）, is proposed in this paper. Firstly, the bare face image detached from the normalized image was convolved w...A novel face recognition method, which is a fusion of muhi-modal face parts based on Gabor feature （MMP-GF）, is proposed in this paper. Firstly, the bare face image detached from the normalized image was convolved with a family of Gabor kernels, and then according to the face structure and the key-points locations, the calculated Gabor images were divided into five parts： Gabor face, Gabor eyebrow, Gabor eye, Gabor nose and Gabor mouth. After that multi-modal Gabor features were spatially partitioned into non-overlapping regions and the averages of regions were concatenated to be a low dimension feature vector, whose dimension was further reduced by principal component analysis （PCA）. In the decision level fusion, match results respectively calculated based on the five parts were combined according to linear discriminant analysis （LDA） and a normalized matching algorithm was used to improve the performance. Experiments on FERET database show that the proposed MMP-GF method achieves good robustness to the expression and age variations.展开更多
This study focuses on non-linear seismic response of concrete gravity quay-wall structures subjected to near-fault ground motions, a subject which seems not to have received much attention in the literature. A two-dim...This study focuses on non-linear seismic response of concrete gravity quay-wall structures subjected to near-fault ground motions, a subject which seems not to have received much attention in the literature. A two-dimensional coupled fluid-structure-soil finite element modelling is employed to obtain the quay-wall response. The seawater medium is represented by acoustic type, potential based fluid elements. The elasto-plastic behavior of the soil medium is idealized using Drucker-Prager yield criterion based on associated flow rule assumption. Four nodded plane strain elements are used to model the concrete wall, foundation, subsoil, backfill and seabed zones. Fluid Structure Interface （FSI） elements are considered between the seawater interfaces with the quay-wall and the seabed. Frictional contact elements are employed between the wall and soil interfaces. The numerical model is validated using field measurements available for permanent drifts in a quay-wall damaged during Kobe earthquake. Reasonable agreements are obtained between the model predictions and the field measurements. Non-linear seismic analyses of the selected quay-wall subjected to both near-fault and far-fault ground motions are performed. An incremental dynamic analysis approach （IDA） is used. In general, at least for models examined in the current study, the gravity quay-walls are found to be more vulnerable to near-field, in comparison with the corresponding far-field, earthquakes.展开更多
This article uses the refined Laspeyres index decomposition method to examine the overall trends and characteristics of carbon emissions in eight Chinese industries for the period 1994-2008. The results show that ever...This article uses the refined Laspeyres index decomposition method to examine the overall trends and characteristics of carbon emissions in eight Chinese industries for the period 1994-2008. The results show that every one percentage point increase in economic scale will result in an average increase of 15 Mt （million tonnes） in carbon emissions. However, different industries vary greatly in terms of marginal carbon emissions caused by economic growth. The economic structure＇s bias toward heavy industry fuels the increase of carbon emissions： every one percentage point rise in the share of manufacturing industry produces an average of 56 Mt carbon emissions. Technological progress helps reduce energy intensity and serves as a core driver in reducing carbon emissions, in that every one percentage point decrease in energy intensity will cause an average reduction of 33 Mt in carbon emissions. Our coal-dominated energy structure has resulted in a persistently high level of carbon emissions, suggesting that the reduction effect brought about by changes in energy structureis not significant. Nevertheless, lowering the density of overall carbon emissions is a positive signal, indicating that China is optimizing its energy structure. Only by promoting industrial restructuring, optimizing energy structure, encouraging energy-saving technologies and technological innovation, and reorienting industry can China achieve low-carbon development and control pollution.展开更多
The structural failure under severe ground motions is primarily caused by their unreasonable seismic failure mode (SFM). This paper provides a methodology aiming at the SFM improvement of reinforced concrete frame str...The structural failure under severe ground motions is primarily caused by their unreasonable seismic failure mode (SFM). This paper provides a methodology aiming at the SFM improvement of reinforced concrete frame structure. An RC frame is modeled and three types of failure criterion are defined as the premise of SFM. Static pushover analysis is adopted to identify the SFM. The dominant failure modes and failure paths of the structure are obtained in three lateral load patterns (inverted trian- gular distribution, uniform distribution and adaptive distribution). Based on the pushover analysis, the sequential failure of components and the probability of the occurrence of plastic hinges are determined. By this, weak components of the structure are detected and herein are strengthened. The project cost of the proposed strengthening strategy increases by 2.4%. Capacity spectrum method is used to study the performance of the strengthening structure. Pushover analysis is conducted again to present the improvement of strength and ductility. Lateral drift and local response through IDA are also studied to indicate that the strengthening of some columns and beams can improve the SFM to enhance the seismic capacity of structure.展开更多
This study presents static and dynamic assessments on the steel structures. Pushover analysis （POA） and incremental dynamic analysis （IDA） were run on moment resisting steel frames. The IDA study involves successi...This study presents static and dynamic assessments on the steel structures. Pushover analysis （POA） and incremental dynamic analysis （IDA） were run on moment resisting steel frames. The IDA study involves successive scaling and application of each accelerogram followed by assessment of the maximum response. Steel frames are subjected to nonlinear inelastic time history analysis for 14 different scaled ground motions, 7 near field and 7 far field. The results obtained from POA on the 3, 6 and 9 storey triangular lateral loading. Uniform loading shows that the steel frames show consistent results for both uniform and steel frames exhibits higher base shear than the triangular loading. The IDA results show that the far field ground motions has caused all steel frame design within the research to collapse while near field ground motion only caused some steel frames to collapse. The POA can be used to estimate the performance-based-seismic-design （PBSD） limit states of the steel frames with consistency while the IDA seems to be quite inconsistent. It is concluded that the POA can be consistently used to estimate the limit states of steel frames while limit state estimations from IDA requires carefully selected ground motions with considerations of important parameters.展开更多
基金This research has been supported by the National Natural ScienceFoundation of China (Grant No. 51778135 )the Natural Science Foundation of JiangsuProvince (Grant No. BK20160207)+1 种基金Aeronautical Science Foundation of China (GrantNo. 20130969010)the Fundamental Research Funds for the Central Universities andPostgraduate Research & Practice Innovation Program of Jiangsu Province (Grant No.KYCX18_0113 and KYLX16_0253).
文摘Current building design codes allow the appearance of structural and nonstructural damage under design basis earthquakes.The research regarding probabilistic seismic loss estimation in domestic building structure is urgent.The evaluation in this paper is based on a 11-story reinforced concrete office building,incremental dynamic analysis(IDA)is conducted in Perform 3D program using models capable to simulate all possible limit states up to collapse.Next,the probability distribution of post-earthquake casualties,rebuild costs repair costs and business downtime loss are calculated in PACT software for the studied building considering the modified component vulnerability groups and population flow models.The evaluation procedure can also shed light on other types of buildings in China.For non-typical functional building structures,this article proposes to build a finite element model of structural components and to classify the vulnerability groups based on the construction drawings,and to supply and improve the vulnerability library of appendages in FEMA P-58 according to the actual situation.In this way,the application scope of building seismic performance evaluation can be expanded.
基金This paper was supported by the National Natural Science Foundation of China[Grant number.72173100,71703130,71803159,71903157]The Soft Science Research Program of Sichuan Province[Grant number.2021JDR0133]the Fundamental Research Funds for the Central Universities[Grant number.JBK2103003,JBK1805006].
文摘The depth and breadth of participation in the global value chain(GVC)significantly impacts a country's fine particulate contamination(PM_(2.5))emissions.First,based on the GVC accounting framework,the sources of PM_(2.5) emissions in China between 1990 and 2015 are identified and investigated considering production-side,consumption-side,and export-implied pollution.Then,index decomposition analysis(IDA)of emissions is conducted to further investigate the changes in and causes of air pollution in China.Throughout the analytical process,differences between the PM_(2.5) emissions in two time periods-one of rapid economic growth and another of the“new normal”economy-are compared.The results demonstrate that:China is embedded in high pollution links of GVCs;China transfers pollution to third-parties by importing intermediate products from resource-intensive countries in the global production system;extensive economic growth caused an increase in China's total PM_(2.5) emissions,but cleaner production technology can reduce the emissions intensity.Industrial restructuring under the“new normal”has increased China's short-term PM_(2.5) emissions intensity.These results suggest that China should optimize and upgrade its domestic economic structure and transform its export growth mode to deliver high added value and low pollution.Further,it should prioritize cooperation between the upstream and downstream value chain and accelerate the upgrading of its consumption structure in this new era.
基金Project(2011CB013804) supported by the National Basic Research Program of ChinaProject(50925828) supported by the National Natural Science Funds for Distinguished Young Scholars of China
文摘Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be expressed either as a likelihood of damage or potential financial loss.Engineers tend to make use of the former(i.e.damage).Nevertheless,other non-technical stakeholders cannot get useful information from damage.However,if financial risk is expressed on the basis of probable monetary loss,it will be easily understood by all.Therefore,it is necessary to develop methodologies which communicate the system capacity and demand to financial risk,Incremental dynamic analysis(IDA) was applied in a performance-based earthquake engineering context to do hazard analysis,structural analysis,damage analysis and loss analysis of a reinforced concrete(RC) frame structure.And the financial implications of risk were expressed by expected annual loss(EAL).The quantitative risk analysis proposed is applicable to any engineering facilities and any natural hazards.It is shown that the results from the IDA can be used to assess the overall financial risk exposure to earthquake hazard for a given constructed facility.The computational IDA-EAL method will enable engineers to take into account the long-term financial implications in addition to the construction cost.Consequently,it will help stakeholders make decisions.
基金Supported by the National Key Technology R&D Program (No. 2006BAK08B07)
文摘A novel face recognition method, which is a fusion of muhi-modal face parts based on Gabor feature （MMP-GF）, is proposed in this paper. Firstly, the bare face image detached from the normalized image was convolved with a family of Gabor kernels, and then according to the face structure and the key-points locations, the calculated Gabor images were divided into five parts： Gabor face, Gabor eyebrow, Gabor eye, Gabor nose and Gabor mouth. After that multi-modal Gabor features were spatially partitioned into non-overlapping regions and the averages of regions were concatenated to be a low dimension feature vector, whose dimension was further reduced by principal component analysis （PCA）. In the decision level fusion, match results respectively calculated based on the five parts were combined according to linear discriminant analysis （LDA） and a normalized matching algorithm was used to improve the performance. Experiments on FERET database show that the proposed MMP-GF method achieves good robustness to the expression and age variations.
文摘This study focuses on non-linear seismic response of concrete gravity quay-wall structures subjected to near-fault ground motions, a subject which seems not to have received much attention in the literature. A two-dimensional coupled fluid-structure-soil finite element modelling is employed to obtain the quay-wall response. The seawater medium is represented by acoustic type, potential based fluid elements. The elasto-plastic behavior of the soil medium is idealized using Drucker-Prager yield criterion based on associated flow rule assumption. Four nodded plane strain elements are used to model the concrete wall, foundation, subsoil, backfill and seabed zones. Fluid Structure Interface （FSI） elements are considered between the seawater interfaces with the quay-wall and the seabed. Frictional contact elements are employed between the wall and soil interfaces. The numerical model is validated using field measurements available for permanent drifts in a quay-wall damaged during Kobe earthquake. Reasonable agreements are obtained between the model predictions and the field measurements. Non-linear seismic analyses of the selected quay-wall subjected to both near-fault and far-fault ground motions are performed. An incremental dynamic analysis approach （IDA） is used. In general, at least for models examined in the current study, the gravity quay-walls are found to be more vulnerable to near-field, in comparison with the corresponding far-field, earthquakes.
基金a stage result supported by the Major Program of the National Social Science Fund of China(08AJY032,07AJY010)Program for New Century Excellent Talents in University of Ministry of Education(NCET-10-0409)
文摘This article uses the refined Laspeyres index decomposition method to examine the overall trends and characteristics of carbon emissions in eight Chinese industries for the period 1994-2008. The results show that every one percentage point increase in economic scale will result in an average increase of 15 Mt （million tonnes） in carbon emissions. However, different industries vary greatly in terms of marginal carbon emissions caused by economic growth. The economic structure＇s bias toward heavy industry fuels the increase of carbon emissions： every one percentage point rise in the share of manufacturing industry produces an average of 56 Mt carbon emissions. Technological progress helps reduce energy intensity and serves as a core driver in reducing carbon emissions, in that every one percentage point decrease in energy intensity will cause an average reduction of 33 Mt in carbon emissions. Our coal-dominated energy structure has resulted in a persistently high level of carbon emissions, suggesting that the reduction effect brought about by changes in energy structureis not significant. Nevertheless, lowering the density of overall carbon emissions is a positive signal, indicating that China is optimizing its energy structure. Only by promoting industrial restructuring, optimizing energy structure, encouraging energy-saving technologies and technological innovation, and reorienting industry can China achieve low-carbon development and control pollution.
基金supported by the National Major Basic Research Program of China (" 973" Project) (Grant No. 2007CB714202)the National Natural Science Foundation of China (Grant No. 90815027)
文摘The structural failure under severe ground motions is primarily caused by their unreasonable seismic failure mode (SFM). This paper provides a methodology aiming at the SFM improvement of reinforced concrete frame structure. An RC frame is modeled and three types of failure criterion are defined as the premise of SFM. Static pushover analysis is adopted to identify the SFM. The dominant failure modes and failure paths of the structure are obtained in three lateral load patterns (inverted trian- gular distribution, uniform distribution and adaptive distribution). Based on the pushover analysis, the sequential failure of components and the probability of the occurrence of plastic hinges are determined. By this, weak components of the structure are detected and herein are strengthened. The project cost of the proposed strengthening strategy increases by 2.4%. Capacity spectrum method is used to study the performance of the strengthening structure. Pushover analysis is conducted again to present the improvement of strength and ductility. Lateral drift and local response through IDA are also studied to indicate that the strengthening of some columns and beams can improve the SFM to enhance the seismic capacity of structure.
文摘This study presents static and dynamic assessments on the steel structures. Pushover analysis （POA） and incremental dynamic analysis （IDA） were run on moment resisting steel frames. The IDA study involves successive scaling and application of each accelerogram followed by assessment of the maximum response. Steel frames are subjected to nonlinear inelastic time history analysis for 14 different scaled ground motions, 7 near field and 7 far field. The results obtained from POA on the 3, 6 and 9 storey triangular lateral loading. Uniform loading shows that the steel frames show consistent results for both uniform and steel frames exhibits higher base shear than the triangular loading. The IDA results show that the far field ground motions has caused all steel frame design within the research to collapse while near field ground motion only caused some steel frames to collapse. The POA can be used to estimate the performance-based-seismic-design （PBSD） limit states of the steel frames with consistency while the IDA seems to be quite inconsistent. It is concluded that the POA can be consistently used to estimate the limit states of steel frames while limit state estimations from IDA requires carefully selected ground motions with considerations of important parameters.
