Comparative analysis of cast-in-place post-tensioned and steel-concrete composite bridge bent caps

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.

Non-stationary Buffeting Response Analysis of Long Span Suspension Bridge Under Strong Wind Loading

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.

Application of LRB isolation technology in continuous girder bridges

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.

Effect of temperature difference load of 32 m simply supported box beam bridge on track vertical irregularity

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.

Effects of polar cortical cytoskeleton and unbalanced cortical surface tension on intercellular bridge thinning during cytokinesis

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.

Design,Synthesis and Crystal Structure of Two One-dimensional Zigzag Chain-like Compounds

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））.

西班牙斜拉-悬吊组合桥——奥里奥大桥

西班牙奥里奥大桥（Orio Bridge,见图1）桥长310m,跨径布置为（65＋180＋65）m,桥面宽22.8m,是一座公路桥。架桥处河道是划船比赛通道,桥梁施工时河道内不能设置临时支墩,且还要考虑环境及景观方面的因素。为解决以上限制条件和预算问题,桥梁结构采用斜拉-悬吊组合结构。

A Corrugated 2D Mn(Ⅱ) Network:[Mn_3(μ-oxalate)_3(μ-4,4'-bpy)_2(4,4'-bpy)_2]_n

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.

Visible-light-induced novel cyclization of 2-(2-(arylethynyl)benzylidene)-malononitrile derivatives with 2,6-di(tert-butyl)-4-methylphenol to bridged spirocyclic compounds

A green and highly efficient strategy for the preparation of bridged spirocyclic compounds via visible-light-induced cyclization of 2-(2-(arylethynyl)benzylidene)malononitrile derivatives with 2,6-di(tert-butyl)-4-methylphenol(BHT)at room temperature was developed.The photoinduced radical reactions generated the corresponding products in good yields under simple and mild reaction conditions.

双—（二烷硫基四硫富瓦烯二硫）金属配合物的合成及性质研究

合成了三种未见文献报道的双-(二烷硫基四硫富瓦烯二硫)金属配合物和三种新的四硫富瓦烯(TTF)桥联的双金属配合物,测定了它们的电导率,讨论了含Ni配合物的电导率优于含Cu,Hg配合物的原因.

Research on New Testing Method and Instrument of Clothing Pressure

This paper discusses the formation of the fabric clothingpressure,the efforts of the human body and the impor-tance of the clothing pressure measurement.Several as-pects such as setting up the scientific and simple measur-ing method of the clothing pressure,the designing andmaking the measuring instruments are emphasized.Bymeans of experimental testing and analysis,some usefulresults can be derived from these works.

日本太田川大桥

太田川大桥（Otagawa Bridge,见图1）位于日本广岛市西区,主桥为6跨连续钢-混凝土复合拱桥,桥长412 m,跨径布置为（40.0＋46.5＋47.0＋116.0＋116.0＋46.5）m。设计荷载为B活荷载,上行线桥面宽9.75~16.235m,下行线桥面宽9.75~12.585m。2011年9月开始施工,工期27个月,2014年3月23日通车。该桥上部结构由PC连续刚构箱梁和单弦钢拱组成,共同分担荷载。

南非在建的2座桥梁

南非姆斯卡巴河桥（Msikaba River Bridge，见图1）是一座长580 m的单跨斜拉桥。桥址位于树木茂密的深谷，两侧是砂岩悬崖。该桥梁底距谷底河面高度约190 m，桥面的施工会遇到严峻的气候挑战。主梁采用钢-混凝土结合梁，桥面宽22.8 m，承载4条车道和2条宽1.4 m的人行道。主梁采用悬臂拼装法施工。该桥建成后，将成为南非跨径最大的斜拉桥。

克罗地亚德拉瓦河桥

德拉瓦河桥（Drava River Bridge ）位于克罗地亚 A5高速公路上，全长2．5 km ，由1座斜拉桥主桥和2座引桥组成，主梁分左、右2幅布置。主桥斜拉桥跨径组成为（100＋220＋100） m ，主梁采用钢-混凝土结合梁。2座引桥均长1000 m ，位于德拉瓦河的漫滩区，主梁采用预制预应力混凝土梁，桥墩为圆柱墩。