Experimental Analysis for Steel Box Concrete Composite Beam of Arch Bridge

A new steel concrete composite structure was proposed which composed of steel box beam, PC beam and PBH Shear connection. Bend test was carried out for the performance study of deformation and stress. It was found that Material advantages of steel and concrete were fully used and crack of concrete and local instability of steel box were avoided. And the deformation between steel box and concrete can be smoothed with PBH shear connection. As the calculated values showed good agreements with the test results, the proposed formulas can be reliably applied to the practice analysis. With the different parameters analysis, mechanic performance of the composite was obtained.     

Construction Technology for Bid Construction Part B of Yangtze River Bridge in Jiangyin City

In this paper, the advanced construction technology and site management applied in bid construction part B of Yangtze River bridge in Jiangyin was presented in detail. This bridge is the largest span bridge in China, where the advanced technology applied is: 3-d coordinate control surveying in bridge tower, small powder for artificial pile, over-form and climb form in construction of tower column, temperature control for casting mass concrete. It is of great value for reference to large bridge building.     

Sensitivity Analysis of Cantilever Box Beam Temperature Effects Based on the Prestressed Concrete Parameter Changes

On the construction of large-span prestressed box beam Cantilever, the parameter frequent changes in concrete modulus E, coefficient of thermal expansion α.In a certain temperature case, the change of concrete parameters will cause the changes on internal stress and strain of the bridge and the difference of the changes will affect the bridge safety. Accordingly,based on a bridge cross-section of a temperature field and combined with the actual bridge construction, give concrete Cantilever bridge parameters change, calculated and analyzed the sphere of influence of parameters on the stress and strain fields of bridge, asked the law of sensitivity on stress changes. Summarize the sensitivity factors of temperature stress which is used to improve bridge safety.     

Mechanical Behaviors of Large Span Space Structures in the Construction Process

Traditional structural design emphasizes checking whether a loaded structure satisfies design requirements without considering the construction process. There is a great difference in structures between the states in construction processes and design, however. To solve the above problems, a method of nonlinear time varying mechanics was adopted to analyze the construction process of a structure. The structural characteristics in each construction stage were analyzed by time varying mechanics and the variations of internal force and displacements obtained. We conclude that designs will not be safe if the time varying effect in the construction process analysis is not considered. We offer advice on the design and construction of large span structures.     

Temperature Field Analysis of Long-span Concrete Box Girders

Taking a two-lane extra large bridge as sample,it is to analyze the real time thermal field and thermal effect on a long-span prestressed concrete box girder. The obtained data is compared with the simulation which is based on a balancing theory of temperature distributions and exchange in box girder exterior surfaces. The results show that the proposed method can emulate the actual boundary conditions precisely, it can satisfy the design analysis requirement of the practice engineering. Based on the emulation of the temperature field, with the ANSYS secondary development technology, FEM modules are developed to analyze the thermal field of the prestressed concrete box girder bridges. The present examples show that the developed modules are effective and useful.     

电子束辐射技术在食品贮藏加工中的应用

电子束辐射加工技术是一项高新技术,结合该技术在国内农产品和食品加工领域的研究与应用情况,综合分析了电子束辐射技术的特点、研究现状和发展前景。     

Experimental Research on Steel Tube Confined Concrete Column Ring Beam Joint with Shear Ring under Direct Shear

In this paper,through direct shear tests on 3 steel tube confined concrete column ring beam joints with shear ring,the ultimate capacity,the mechanical mechanism,the sliding of ring beam relative to steel tube and the ultimate failure mode of ring beam were analyzed.The results showed that the ultimate failure mode and the calculation of capacity of ring beam joint awaited further tests and analysis.     

Shear Lag Effect of Concrete Box Girders Considered Varying Flange-depths

According to concrete box beam which flanges depth varying along the orientation of cross section, using variational principle of potential energy, new analysis method of shear lag is proposed for single cell concrete box beam. For simply supported girders and cantilever girders, general analysis of varying flange-depths influence on positive and negative shear-lag effect and deflection have be done. It's shown that varying flange-depths have influence both on sectional stress and deflection. Considering the varying flange-depths have effect on the calculation results of up to 15%.     

烤烟箱式堆积烘烤工艺的探究

为探索适应现代烟草农业专业化烘烤技术新模式,开展了箱式堆积烘烤技术的研究。结果表明,与常规密集烘烤相比,箱式堆积烤房具有装烟量大、烘烤操作便捷的优点,可大幅度减轻劳动强度,降低用工成本,使烟农从繁琐的编烟、装烟和出炉的劳动中解脱出来;其装烟量约为常规密集烘烤的1.9倍,烘烤环节用工成本降低50%以上、耗能成本降低16%以上,能耗显著降低,具有较好的应用前景。此外,箱式堆积烘烤烤后外观品质和化学成分含量无明显差异。     

Comparative Study of Construction Cost between Trench and Trenchless Technology

This paper compares the construction costs of trench technology with that of trenchless technology and emphasizes the importance of technological economy during the construction of underground pipeline. It analyzes the present situation in construction of underground pipeline. It also points out the significance of social sustainable development in engineering construction.     

Construction Technology for the Main Bridge Pier of Citong Bridge in Quanzhou City

The Citong Bridge is located in the river estuary section with 4 meter tide range and mixed geological structure. In this paper, the technique for construction of the main bridge pier was presented in detail, which consists of the construction process, technological requirements, main construction parameters and amendment on defects. It is of great value for reference to the similar works.     

Test and Finite Analysis to Non-strong Column and Weak Beam Concrete Frames

Through the test of two concrete frames under vertical load and nonlinear finite programme analysis,the performances of strong beam with weak column and equal strength column and beam are studied,such as ultimate load,deflection,displacement ductility,redistribution of internal force.When the reinforcement is proper,the research proved that strong beam with weak column" and "equal strength column and beam" have better displacement ductility and can realize full redistribution of internal force,the width of cracks and deflections can satisfy the rules of code for design of concrete structures.     

A Study on the Test Method of Post-tensioned Prestressed Concrete Continuous Beam

A test method of post-tensioned prestressed concrete continuous beam is presented in this paper.In the test,the prestressed secondary moment is established by adjusting middle support height.The prestressed concrete continuous beam built by the method is equivalent to the beam in practice.     

Simulation Analysis of Flexural Performance of Reinforced Concrete Beam in Salt-frost Environment

Considering the damage of concrete mechanical properties and bonding behavior between the steel bar and concrete after the freezing and thawing function in the numerical simulation, the nonlinear analysis on flexural performance of reinforced concrete beam which experiences different salt-frost cycles is conducted, and the evolution law of resistance performance of reinforced concrete beam is studied. It is shown that, in the salt-frost environment, the decrease of concrete mechanical properties is the main reason that causes the degeneration of RC beam on flexural performance, while the reduction of bonding property has an unobvious effect on the beam resistance performance. When the salt-frost cycles reach a certain level, the beam failure pattern would change from the under-reinforced failure to over-reinforced failure. The freeze-thaw damage of bonding property in the beam-ends anchorage zone has a certain effect on the beam resistance behavior, especially for the more serious freeze-thaw degree, the resistance performance of the beam reduces about 4% than the perfect anchor beam.     

Experimental Analysis of Simply-Supported Concrete Box Girder with Web Openings model Under Double Uniformly Distributed Load

In order to satisfy the demand of the double-deck traffic in city, a concrete box girder model with rectangular web openings was designed with ratio of 1:6. Experimental study was carried out to investigate the flexural capacity of the model girder with double uniformly distributed load. The finite element model was established based on the experiment and the results agreed with measurement results. The effect of the web openings on the girder was explored. The results demonstrated that the deflection caused by load on bottom plate of box girder was 9.7% more than that of load on the top plate. The deflection of girder with web opening is 22.9%~28.1% greater than that of girder without web opening. Compared with girder without web opening, the shear lag of girder with web opening increased, of which the maximum value was 62.0% in various working conditions. simply-supported concrete box girder with web openings under double uniformly distributed load affect the flexural capacity.     

专业镇技术创新平台的构建机理分析

构建专业镇技术创新平台这个重要载体,对解决专业镇产业共性技术难题,提高中小企业自主创新能力,促进产业结构优化升级和产业集聚,最终实现专业镇经济可持续发展,具有重要的现实意义。本文在分析专业镇技术创新平台概念、平台结构及内在关系的基础上,对专业镇技术创新平台的构建机理进行深入分析,重点提出非零和合作博弈;优势互补,创造协同效应;资源共享,风险分担;合作创新,节约交易成本等构建机理,为专业镇技术创新平台的构建、运行机制的设计及保障措施的安排提供理论依据。