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Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The construction technology of precast segment is of great significance in promoting green, low-carbon and sustainable development of bridge construction. In order to expand the application range of segmental prefabrication technology, it needs to be further researched and improved. According to the research results of prefabricated and assembled bridges at home and abroad, the research progresses of the overall performance evaluation of the bridge, joint design, key construction technology and simulation analysis are reviewed. The results show that researches are insufficient on such problems as structural adhesive aging and adhesive-concrete interface aging, uneven distribution of shear stress of key teeth, mechanical properties of joints under the combined action of bending, bending and shearing; researches are absent on the theory related to segmental precast bridge construction technology; and researches are few on the whole process of construction structure simulation and simulation analysis. In view of the problems existing in the research on segmental precast bridge technology, it is necessary to further improve the theoretical research on segmental precast bridge, formulate corresponding specifications, increase the research on key technology in design and construction, strengthen information management and realize the development of the whole life cycle, etc. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering Management / Gongcheng Guanli Xuebao is the property of Journal of Engineering Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To optimize the design of girder bridge, the proper cell number of the two-lane CSWs PC box girder was investigated. Based on the two-lane CSWs PC box girder bridge design parameter, the mechanical behaviors of single-room girder box with single cell to five cells were analyzed under four different load conditions by finite element analysis (FEA).The mid-span displacement in the bottom flange, the von-Mises shear stress in both corrugated web sides, the normal warping stress and the natural frequency of the box girders were obtained. The results show that multiplying cell numbers can increase the prestressing efficiency and decrease the von-Mises shear stress in both corrugated web sides in some cases. However, with the cell number increasing, the normal warping stress under eccentric load and the dead weight of the girder are increased dramatically. By simple formula method and principal component analysis method, the proper cell number for the two-lane CSWs PC box girder is suggested. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Guangdong University of Technology is the property of Journal of Guangdong University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the technical guide of highway bridge construction monitoring, the deformation laws of arch ribs of steel bridges were investigated through monitoring the displacement and the internal stress of arch rib at each construction stage in real time. The results show that the variation interval of vertical displacement of steel bridge arch rib at L／4 and 3L／4 is from 0.30 to 13.50 mm under different working conditions, and the vertical displacement range of L／2 is from 0.25 to 11.40 mm under different working conditions. The direction of displacement is vertical downward. The stress range of the arch legs at both ends of the steel arch ribs varies from 6.79 to 26.53 MPa under various working conditions, and the variation range of stress at L／4 and 3L／4 is from 1.60 to 27.93 MPa under various working conditions. The stress variation range at L／2 is from 0.21 to 11.49 MPa under various working conditions, and the stress change is compressive stress. The stress deformation change trend of the symmetrical position for the full span arch rib is consistent, and the whole arch rib produces the maximum displacement change and the internal stress change after the suspender is tensioned under the working condition 2.The construction phase can be used as the key monitoring condition of forced deformation. [ABSTRACT FROM AUTHOR]

Wave and current loads on pile foundation of sea-crossing bridges have always been given priority in the design of sea-crossing bridges. The wave-current force in practical projects is usually obtained by the computing method of wave-current force for single pile foundation recommended in the Code of Hydrology for Harbour and Waterway ( JTS145—2015), without reasonable consideration of the influence of local scour shape. In this study. Hong Kong-Zhuhai-Macao Bridge has been taken as an example. Based on physical model test results, a calculation method of wave-current force for pile foundation considering local scour patterns is proposed by modifying the selection of such parameters as velocity, CD and 6'M in the calculation model. The proposed method, which guarantees the project safety and can be cost-effective as well, has been successfully applied to the design of pile foundation of Hong Kong-Zhu-hai- Macao Bridge. [ABSTRACT FROM AUTHOR]

The being built Hongkong-Zhuhai-Macao Bridge is about 50 km, and the major project of bridge and tunnel in the sea is 35.6 km, with a design life of 120 years and 6 years long construction period. This project has the longest mileage, largest investment and the biggest difficulty in construction in China construction history of sea-crossing bridge. In order to accelerate the progress and improve the quality, the technology of the integration of precast and aquatic installation is used in the pile caps and piers of the non -navigable bridges. Deep water pier is divided into two/three prefabrication, and prestressed rolling continuous external thread bars are settled in the pier, with a diameter of 75 mm, yield strength of 830 MPa, and tensile strength of 1 030 MPa. All the installation of steel bar and part of the tensioning of the bottom section pier are completed in the pier precasting yard. The rest of the connection, tensioning, and grouting of the prestressed steel bar are conducted in the water conservancy project site. We emphatically expounded the technical process of the installation of CB03 in pier precast yard and tensioning prestressed steel bars in Hongkong-Zhuhai-Macao Bridge project , which has certain reference value to similar construction engineering projects. [ABSTRACT FROM AUTHOR]

Grass bridges (caoqiao) were floating bridges made of grass, twigs, and ropes that enabled river crossing at different water levels -- due to seasonal change -- in North China. Prior to modern architectural technology, these temporary grass bridges were popular. This article discusses the building of grass bridges over the Zhang River during the Qing dynasty. The Zhang River grass bridges were built in the fall, when water levels were low, and removed in spring, when water levels rose. The locations of these bridges changed each year. Because these bridges often crossed county borders, conflicts sometimes arose over which jurisdiction was financially responsible for construction. The ecological impact and location selection of the bridges are also analyzed.