Making decisions of when to intervene on bridges taking into consideration more than owner costs is a growing field of interest in earthquake engineering. In particular, bridges can be considered critical links in hig...Making decisions of when to intervene on bridges taking into consideration more than owner costs is a growing field of interest in earthquake engineering. In particular, bridges can be considered critical links in highway networks because of their seismic vulnerability in terms of direct and indirect losses. This paper aims at defining a general criteria capable of taking into account both these costs in a simplified and efficient formulation. Indirect losses generally neglected elsewhere, are taken into consideration by applying a formulation that assesses investment efficiency. The presented formulation follows the one proposed for buildings by L. Kantorovich, 1975. Direct costs are computed from a Performance Based Earthquake Engineering （PBEE） methodology by the Pacific Earthquake Engineering Research （PEER） center. The problem considers two competitive objectives （maximizing economic efficiency and minimizing costs） in a multi-objective structural optimization procedure. The formulation has been applied to a case study aimed at strengthening a benchmark bridge. The optimum investment has been assessed between several isolated configurations.展开更多
The complexity of the IH-635 Managed Lanes Project, located in Dallas County, Texas, posed several technical and constructive challenges, leading to the adoption of solutions different from the traditional. Two altern...The complexity of the IH-635 Managed Lanes Project, located in Dallas County, Texas, posed several technical and constructive challenges, leading to the adoption of solutions different from the traditional. Two alternative solutions for the pier cap on one of the bridge crossings over IH-35E in the IH-635 project were analyzed in this case study, a cast-in-place post-tensioned concrete cap and an innovative prefabricated steel-concrete com- posite cap. The approach was to use an estimation of direct costs for material and labor and consideration of con- struction time schedules. A supplementary numerical modeling confirmed that both alternatives behave elasti- cally under imposed loads. The direct cost of material and labor for the two alternatives were close. However, the composite alternative required 13 days less construction time, resulting in substantial cost savings from traffic closing in the very busy traffic corridor. Traffic closing costs were substantially higher than the direct costs, especially for the post-tensioned cap. The quantification of the benefits allows more confidence in the utilization of the composites caps, leading to faster completion of bridge projects and substantial economic savings.展开更多
The non-stationary buffeting response of long span suspension bridge in time domain under strong wind loading is computed. Modeling method for generating non-stationary fluctuating winds with probabilistic model for n...The non-stationary buffeting response of long span suspension bridge in time domain under strong wind loading is computed. Modeling method for generating non-stationary fluctuating winds with probabilistic model for non-stationary strong wind fields is first presented. Non-stationary wind forces induced by strong winds on bridge deck and tower are then given a brief introduction. Finally,Non-stationary buffeting response of Pulite Bridge in China,a long span suspension bridge,is computed by using ANSYS software under four working conditions with different combination of time-varying mean wind and time-varying variance. The case study further confirms that it is necessity of considering non-stationary buffeting response for long span suspension bridge under strong wind loading,rather than only stationary buffeting response.展开更多
This paper summarizes the superiority of lead-rubber beating （LRB） continuous girder bridges. The research method for isolation performance is discussed when pile-soil interaction is considered. By the finite elemen...This paper summarizes the superiority of lead-rubber beating （LRB） continuous girder bridges. The research method for isolation performance is discussed when pile-soil interaction is considered. By the finite element method and self-compiling program, a systematic study of the reliability of LRB continuous girder bridges is given by the use of different indicators, including the riding comfort of the LRB system, the pounding and dynamic stability when the LRB system is subjected to seismic excitations, and the reliability of the LRB system when subjected to other common horizontal loads. The results show that the LRB system has obvious advantages over the traditional continuous girder structure. The LRB isolation effect remains good even when pile-soil interaction is considered; the vertical rigidity of the LRB guarantees desirable riding comfort. The LRB demonstrates good reliability when subjected to the effects of braking, wind loads and temperature. However, it is also pointed out that the pounding of the LRB system subjected to earthquakes must be avoided, and the dynamic stability may be reduced when the LRB system has higher piers and generates a larger displacement in a strong earthquake. Useful advice and guidance are proposed for engineering application.展开更多
In order to study the effect of temperature difference load （TDL） along the vertical direction of a simply supported beam bridge section on the vertical irregularity, a rail-bridge-piers calculation model was establ...In order to study the effect of temperature difference load （TDL） along the vertical direction of a simply supported beam bridge section on the vertical irregularity, a rail-bridge-piers calculation model was established. Taking 32 m simply supported box beam bridge which is widely used in the construction of pas- senger dedicated line in China as an example, influences of the temperature variation between the bottom and top of the bridge, temperature curve index, type of temperature gradient, and beam height on track vertical irregularity were analyzed with the model. The results show that TDL has more effects on long wave track irregularity than on short one, and the wavelength mainly affected is approxi- mately equal to the beam span. The amplitude of irregu- larity caused by TDL is largely affected by the temperature variation, temperature curve index, and type of temperature gradient, so it is necessary to monitor the temperaturedistribution of bridges in different regions to provide accurate calculation parameters. In order to avoid the irregularity exceeding the limit values, the height of 32, 48, and 64 m simply supported box beam bridges must not be less than 2.15, 3.2, and 4.05 m, respectively.展开更多
To probe the contributions of polar cortical cytoskeleton and the surface tension of daughter cells to intercellular bridge thinning dynamics during cytokinesis,we applied cytochalasin D（CD） or colchicine（COLC） in...To probe the contributions of polar cortical cytoskeleton and the surface tension of daughter cells to intercellular bridge thinning dynamics during cytokinesis,we applied cytochalasin D（CD） or colchicine（COLC） in a highly localized manner to polar regions of dividing normal rat kidney（NRK） cells.We observed cellular morphological changes and analyzed the intercellular bridge thinning trajectories of dividing cells with different polar cortical characteristics.Global blebbistatin（BS） application was used to obtain cells losing active contractile force groups.Our results show that locally released CD or colchicine at the polar region caused inhibition of cytokinesis before ingression.Similar treatment at phases after ingression allowed completion of cytokinesis but dramatically influenced the trajectories of intercellular bridge thinning.Disturbing single polar cortical actin induced transformation of the intercellular bridge thinning process,and polar cortical tension controlled deformation time of intercellular bridges.Our study provides a feasible framework to induce and analyze the effects of local changes in mechanical properties of cellular components on single cellular cytokinesis.展开更多
Two one-dimensional chain-like cyanide-bridged compounds, [Fe（Phen）2（CN）2Ni（Cyclam）]（ClO4）2·DMF-2H2O 1 （Cyclam = 1,4,8,11-tetraaza-cyclotetradecane, Phen = 1,10-phenanthroline, and DMF = N,N-dimethylform...Two one-dimensional chain-like cyanide-bridged compounds, [Fe（Phen）2（CN）2Ni（Cyclam）]（ClO4）2·DMF-2H2O 1 （Cyclam = 1,4,8,11-tetraaza-cyclotetradecane, Phen = 1,10-phenanthroline, and DMF = N,N-dimethylformamide） and [Fe（Phen）2（CN）2Zn（Cyclam）]（PF6）2·CH3CN 2, were prepared by the reaction of [Fe（Phen）2（CN）2]·2H2O with M（Cyclam）^2＋ （M = Ni, Zn）. In complexes 1 and 2, the metal atoms are connected alternatively with CN groups. X-ray structure and IR analyses for 1 and 2 were performed. Structure analysis revealed that both complexes are centrosymmetric and the geometry around each metal atom is an octahedron. The two complexes crystallize in triclinic with space group of P^1-. For 1, a = 10.439（4）, b = 14.976（7）, c = 15.914（8）A,α = 83.168（15）, β = 74.338（15）, γ = 78.023（15）°, V = 2338.3（18）A^3, Z = 2, Mr = 1035.37, Dc = 1.471 g/cm^3, F（000） = 1076,μ = 0.895 mm^-1, the final R = 0.0616 and wR = 0.1414 for 5849 observed reflections （1 〉 2σ（I））. For 2, a = 9.656（6）, b = 15.404（9）, c = 15.822（10）A, α = 78.68（2）, β= 78.917（19）, γ = 77.15（2）°, V = 2223（2）A^3, Z = 2, Mr = 1064.87, Dc = 1.587 g/cm^3, F（000） = 1078,μ = 1.032 mm^-1, the final R = 0.0672 and wR = 0.1595 for 6819 observed reflections （I 〉 2σ（I））.展开更多
The complexity of the Hong Kong-ZhuhaiMacao Bridge and the political environment of "One country, Two systems" have brought a vital influence on the decision-making recognition, decision-making analysis, and...The complexity of the Hong Kong-ZhuhaiMacao Bridge and the political environment of "One country, Two systems" have brought a vital influence on the decision-making recognition, decision-making analysis, and decision-making management related to this crossborder infrastructure mega-project. Based on case study,this study systematically analyzes the complexity of the decision-making related to the Hong Kong-Zhuhai-Macao Bridge, and explains the general principles that were used for its decision-making management. The research examines the decision-making management system of the Hong Kong-Zhuhai-Macao Bridge, its adaptive behavior, and specific coordination mechanism on different decisionmaking problems in different decision-making stages. This result provides reference for decision-making management system design of cross-border projects.展开更多
The title complex, [Mn3（μ-oxalate）3（μ-4,4′-bpy）2（4,4′-bpy）2]n, was synthesized and structurally characterized by X-ray crystallography. It crystallizes in the monoclinic, space group P2 1/c with a = 16.3222...The title complex, [Mn3（μ-oxalate）3（μ-4,4′-bpy）2（4,4′-bpy）2]n, was synthesized and structurally characterized by X-ray crystallography. It crystallizes in the monoclinic, space group P2 1/c with a = 16.3222（6）, b = 16.2594（5）, c = 16.4885（5） A, β = 94.9900（10）°, V= 4359.3（2） A^3, Z = 4, Mn3C46N8O12H32, Mr = 1053.62, Dc = 1.605 g/cm^3, F（000） = 2140 and μ（MoKa） = 0.932 mm^-1. The structure was refined to R = 0.0578 and wR = 0.1061 for 4795 observed reflections （I 〉 2σ（I））. The oxalate anions behave as the bridging ligand and link two manganese atoms repeatedly to form infinite one-dimensional chains which further extend into a two-dimensional network by bridging 4,4′-bpy ligands.展开更多
文摘Making decisions of when to intervene on bridges taking into consideration more than owner costs is a growing field of interest in earthquake engineering. In particular, bridges can be considered critical links in highway networks because of their seismic vulnerability in terms of direct and indirect losses. This paper aims at defining a general criteria capable of taking into account both these costs in a simplified and efficient formulation. Indirect losses generally neglected elsewhere, are taken into consideration by applying a formulation that assesses investment efficiency. The presented formulation follows the one proposed for buildings by L. Kantorovich, 1975. Direct costs are computed from a Performance Based Earthquake Engineering （PBEE） methodology by the Pacific Earthquake Engineering Research （PEER） center. The problem considers two competitive objectives （maximizing economic efficiency and minimizing costs） in a multi-objective structural optimization procedure. The formulation has been applied to a case study aimed at strengthening a benchmark bridge. The optimum investment has been assessed between several isolated configurations.
基金herein for allowing the use of various data from the LBJ Project in the development of this paper
文摘The complexity of the IH-635 Managed Lanes Project, located in Dallas County, Texas, posed several technical and constructive challenges, leading to the adoption of solutions different from the traditional. Two alternative solutions for the pier cap on one of the bridge crossings over IH-35E in the IH-635 project were analyzed in this case study, a cast-in-place post-tensioned concrete cap and an innovative prefabricated steel-concrete com- posite cap. The approach was to use an estimation of direct costs for material and labor and consideration of con- struction time schedules. A supplementary numerical modeling confirmed that both alternatives behave elasti- cally under imposed loads. The direct cost of material and labor for the two alternatives were close. However, the composite alternative required 13 days less construction time, resulting in substantial cost savings from traffic closing in the very busy traffic corridor. Traffic closing costs were substantially higher than the direct costs, especially for the post-tensioned cap. The quantification of the benefits allows more confidence in the utilization of the composites caps, leading to faster completion of bridge projects and substantial economic savings.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51408174)Anhui Provincial Natural Science Foundation(Grant No.1408085QE95)+1 种基金China Postdoctoral Science Foundation(Grant No.2013M540511 and 2015T80652)Key University Science Research Project of Anhui Province(Grant No.KJ2016A294)
文摘The non-stationary buffeting response of long span suspension bridge in time domain under strong wind loading is computed. Modeling method for generating non-stationary fluctuating winds with probabilistic model for non-stationary strong wind fields is first presented. Non-stationary wind forces induced by strong winds on bridge deck and tower are then given a brief introduction. Finally,Non-stationary buffeting response of Pulite Bridge in China,a long span suspension bridge,is computed by using ANSYS software under four working conditions with different combination of time-varying mean wind and time-varying variance. The case study further confirms that it is necessity of considering non-stationary buffeting response for long span suspension bridge under strong wind loading,rather than only stationary buffeting response.
基金The National Natural Science Foundation of China(No.51008134)
文摘This paper summarizes the superiority of lead-rubber beating （LRB） continuous girder bridges. The research method for isolation performance is discussed when pile-soil interaction is considered. By the finite element method and self-compiling program, a systematic study of the reliability of LRB continuous girder bridges is given by the use of different indicators, including the riding comfort of the LRB system, the pounding and dynamic stability when the LRB system is subjected to seismic excitations, and the reliability of the LRB system when subjected to other common horizontal loads. The results show that the LRB system has obvious advantages over the traditional continuous girder structure. The LRB isolation effect remains good even when pile-soil interaction is considered; the vertical rigidity of the LRB guarantees desirable riding comfort. The LRB demonstrates good reliability when subjected to the effects of braking, wind loads and temperature. However, it is also pointed out that the pounding of the LRB system subjected to earthquakes must be avoided, and the dynamic stability may be reduced when the LRB system has higher piers and generates a larger displacement in a strong earthquake. Useful advice and guidance are proposed for engineering application.
基金supported by the National Science Foundation (U1234201)the Doctorial Innovation Fund of Southwest Jiaotong University
文摘In order to study the effect of temperature difference load （TDL） along the vertical direction of a simply supported beam bridge section on the vertical irregularity, a rail-bridge-piers calculation model was established. Taking 32 m simply supported box beam bridge which is widely used in the construction of pas- senger dedicated line in China as an example, influences of the temperature variation between the bottom and top of the bridge, temperature curve index, type of temperature gradient, and beam height on track vertical irregularity were analyzed with the model. The results show that TDL has more effects on long wave track irregularity than on short one, and the wavelength mainly affected is approxi- mately equal to the beam span. The amplitude of irregu- larity caused by TDL is largely affected by the temperature variation, temperature curve index, and type of temperature gradient, so it is necessary to monitor the temperaturedistribution of bridges in different regions to provide accurate calculation parameters. In order to avoid the irregularity exceeding the limit values, the height of 32, 48, and 64 m simply supported box beam bridges must not be less than 2.15, 3.2, and 4.05 m, respectively.
基金supported by the National Natural Science Foundation of China (10672114)the Natural Science Foundation of Shanxi Province (2007011011)
文摘To probe the contributions of polar cortical cytoskeleton and the surface tension of daughter cells to intercellular bridge thinning dynamics during cytokinesis,we applied cytochalasin D（CD） or colchicine（COLC） in a highly localized manner to polar regions of dividing normal rat kidney（NRK） cells.We observed cellular morphological changes and analyzed the intercellular bridge thinning trajectories of dividing cells with different polar cortical characteristics.Global blebbistatin（BS） application was used to obtain cells losing active contractile force groups.Our results show that locally released CD or colchicine at the polar region caused inhibition of cytokinesis before ingression.Similar treatment at phases after ingression allowed completion of cytokinesis but dramatically influenced the trajectories of intercellular bridge thinning.Disturbing single polar cortical actin induced transformation of the intercellular bridge thinning process,and polar cortical tension controlled deformation time of intercellular bridges.Our study provides a feasible framework to induce and analyze the effects of local changes in mechanical properties of cellular components on single cellular cytokinesis.
基金the grants from 973 Program (2007CB815301 and 2006CB932904)the National Natural Science Foundation of China (20333070 and 20673118)+1 种基金the Science Foundation of CAS (KJCX2-YW-M05)Fujian Province (2006L2005, 2006F3132 and 2007J0171)
文摘Two one-dimensional chain-like cyanide-bridged compounds, [Fe（Phen）2（CN）2Ni（Cyclam）]（ClO4）2·DMF-2H2O 1 （Cyclam = 1,4,8,11-tetraaza-cyclotetradecane, Phen = 1,10-phenanthroline, and DMF = N,N-dimethylformamide） and [Fe（Phen）2（CN）2Zn（Cyclam）]（PF6）2·CH3CN 2, were prepared by the reaction of [Fe（Phen）2（CN）2]·2H2O with M（Cyclam）^2＋ （M = Ni, Zn）. In complexes 1 and 2, the metal atoms are connected alternatively with CN groups. X-ray structure and IR analyses for 1 and 2 were performed. Structure analysis revealed that both complexes are centrosymmetric and the geometry around each metal atom is an octahedron. The two complexes crystallize in triclinic with space group of P^1-. For 1, a = 10.439（4）, b = 14.976（7）, c = 15.914（8）A,α = 83.168（15）, β = 74.338（15）, γ = 78.023（15）°, V = 2338.3（18）A^3, Z = 2, Mr = 1035.37, Dc = 1.471 g/cm^3, F（000） = 1076,μ = 0.895 mm^-1, the final R = 0.0616 and wR = 0.1414 for 5849 observed reflections （1 〉 2σ（I））. For 2, a = 9.656（6）, b = 15.404（9）, c = 15.822（10）A, α = 78.68（2）, β= 78.917（19）, γ = 77.15（2）°, V = 2223（2）A^3, Z = 2, Mr = 1064.87, Dc = 1.587 g/cm^3, F（000） = 1078,μ = 1.032 mm^-1, the final R = 0.0672 and wR = 0.1595 for 6819 observed reflections （I 〉 2σ（I））.
基金funded by the National Natural Science Foundation of China(Grant Nos.71571098,71390520 and 71390521)Fundamental Research Funds for the Central Universities(011814380023)+1 种基金Key Laboratory for Public Projects Audit of Jiangsu Province(GGSS2016-01)the program B for Outstanding Ph.D candidate of Nanjing University(201701B009)
文摘The complexity of the Hong Kong-ZhuhaiMacao Bridge and the political environment of "One country, Two systems" have brought a vital influence on the decision-making recognition, decision-making analysis, and decision-making management related to this crossborder infrastructure mega-project. Based on case study,this study systematically analyzes the complexity of the decision-making related to the Hong Kong-Zhuhai-Macao Bridge, and explains the general principles that were used for its decision-making management. The research examines the decision-making management system of the Hong Kong-Zhuhai-Macao Bridge, its adaptive behavior, and specific coordination mechanism on different decisionmaking problems in different decision-making stages. This result provides reference for decision-making management system design of cross-border projects.
文摘The title complex, [Mn3（μ-oxalate）3（μ-4,4′-bpy）2（4,4′-bpy）2]n, was synthesized and structurally characterized by X-ray crystallography. It crystallizes in the monoclinic, space group P2 1/c with a = 16.3222（6）, b = 16.2594（5）, c = 16.4885（5） A, β = 94.9900（10）°, V= 4359.3（2） A^3, Z = 4, Mn3C46N8O12H32, Mr = 1053.62, Dc = 1.605 g/cm^3, F（000） = 2140 and μ（MoKa） = 0.932 mm^-1. The structure was refined to R = 0.0578 and wR = 0.1061 for 4795 observed reflections （I 〉 2σ（I））. The oxalate anions behave as the bridging ligand and link two manganese atoms repeatedly to form infinite one-dimensional chains which further extend into a two-dimensional network by bridging 4,4′-bpy ligands.
