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During the long-term operation of high-speed railway in our country, affected by various factors such as surrounding environment changes and human engineering activities, large lateral deviation occurs in some line bridge sections, which seriously affects the normal and safe operation of the train and needs to be rectified urgently. Based on the analysis of the principle of bridge rectification by high pressure jet grouting, the theoretical calculation model of bridge rectification is established, and the differential equations of pile deflection, rotation angle, bending moment and shear force under the high pressure jet grouting rectification mode and the analytical formula of pier top displacement are deduced based on the elastic foundation beam theory. Then,by comparing the calculated displacement at the top of the pier with the actual offset of the line,the feasibility of high pressure jet grouting technology for bridge rectification is analyzed, and the rectification effect is verified by typical engineering cases on site. Research shows that the top displacement of pier is related to foundation coefficient and excess pore water pressure generated by high pressure jet grouting; when foundation coefficient and excess pore water pressure take 1 MPa/ m and 80.3 kPa respectively,the top theoretical calculated displacement of pier is 81.8 mm,which is much larger than the actual deviation of ballastless track line of common high speed railway;In the bridge rectification project of a high speed railway Songjiang Grand Bridge,the displacement at the top of the pier calculated by the average value of the measured excess pore water pressure 30.4 kPa 6. 4~31. 0 mm,which is also greater than the maximum deviation 18.2 mm of the line, indicating that the high pressure jet grouting technology is feasible for bridge rectification theoretically;After rectification construction,the bridge and track structure are stable,the line alignment is smooth,and there is no abnormality in the normal speed operation for many years. The theory and practice have proved that the high pressure jet grouting method is a practical and feasible technical measure for bridge rectification. [ABSTRACT FROM AUTHOR]

With the construction of high-speed railway entering a new period, the frequency of railway viaduct stations has increased dramatically. When the pier is high, the space under the viaduct station has a large demand for utilization. Due to the rigidity control, the conventional pier layout is relatively dense, it is likely to form the phenomenon of "pier forest", which is not conducive to space utilization and has poor aesthetics. In order to find a reasonable structural system suitable for high pier viaduct station, this paper takes Dingyuan viaduct station of Hefei-Xinyi High-speed Railway as the engineering background, the existing problems of common structural systems are studied in the design, and a bridge structural system of sparse-piers and semi-integral viaduct station is proposed. This structural system adopts prestressed beam portal pier with cantilever with two inclined columns, which greatly reduces the number and volume of piers, and maintains good mechanical properties. A kind of fixed support which can release horizontal force is innovatively proposed, which improves the overall stiffness of the structure by changing the structural restraint system. Compared with common structural systems, it can greatly improve the utilization efficiency of the space under the bridge, greatly reduce the structure size and top displacement of piers, and has good aesthetics, practicality and structural mechanical performance. It provides a new idea for the bridge structure design of high-speed railway and other rail bridge viaduct stations. [ABSTRACT FROM AUTHOR]

The proportion of bridge structure in the suburban railway is relatively high, and combined with station track design, the turnout structure inevitably needs to be set on the continuous beam before and after the elevated station. On account of the fact that the turnout type, bridge structure and design load of suburban railway are obviously different from high-speed railway, the research on the distance from welded turnout to bridge joint is relatively lacking. Due to the design speed of suburban railway being higher than that of subway, wheel and rail force being larger and the vibration and impact between wheel and rail having a great impact on the surrounding environment, the continuous welded rail with welded turnout technology is adopted on bridge. Based on the turnout-bridge interaction principle, the finite element model of turnout-slab-beam-pier No. 12 ballastless track continuous welded turnout is established, the distance between the commonly used welded single turnout and 4.3 m spacing crossing turnout to the bridge joint is calculated and analyzed and its influence rules are studied. Based on the turnout rail strength, the displacement value of point of switch and frog, relative displacement of stock rail and bridge at switch machine and the rail broken gap value as the limit conditions, the reasonable distance from welded turnout to bridge joint is proposed. The result of research shows that the greater the distance between welded turnout to bridge joint, the displacements of point of switch and frog and relative displacement of stock rail and bridge at switch machine decrease more obviously, the expansion force and braking force of the turnout rail have little difference. The distance from the start and end of the turnout to the bridge joint in warm areas is not less than 10m and for the cold areas it is not less than 18m. Related research results are incorporated into the code for design of suburban railway. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design 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 Railway Standard Design is the property of Railway Standard Design 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 Railway Standard Design is the property of Railway Standard Design 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.)

Jiyang Yellow River highway-railway combined bridge is the key control project of Jinan-Binzhou Railway. Combined with the control factors along the line, the three bridge sites in this section are compared comprehensively and selected in terms of technology and economy, and finally the scheme of highway-railway combined bridge site crossing the yellow river with the planned G308 is selected due to the fact that it saves channel resources, has a small flow angle with the main river channel, enjoys good flood discharge conditions and is in line with the conditions of Jiyang station. On this bridge site, subject to flood control, navigation and structural restrictions, the unequal span scheme of (228+240+300) m in the main channel is determined. According to the requirements of the span and height limit of the airport, three types of bridge schemes of the main bridge of the highway-railway combined super-large bridge are put forward, including steel truss low-pylon cable-stayed bridge, continuous steel truss bridge with upper stiffening and steel box low-pylon cable-stayed bridge. The three schemes share the same span arrangement of (72 + 144 + 228 + 240 + 300+132 + 84) m. Through comparison and analysis of multiple factors such as structural stress, construction scheme, connection conditions and technical economy, it is found that all the three bridge schemes could meet the functional requirements of the structure. The steel box low-pylon cable-stayed bridge with highway and railway on the same deck could reduce the elevation of highway bridge, but the highway connection conditions are poor. The stiffness of the continuous steel truss bridge with upper stiffening is the largest, but the steel consumption is also the largest and uneconomic. Finally, the steel truss girder low-pylon cable-stayed bridge type with highway and railway on different decks is recommended. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design 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 Railway Standard Design is the property of Railway Standard Design 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 Railway Standard Design is the property of Railway Standard Design 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.)

In order to study the driving safety on the main bridge of Quanzhou Bay Sea-Crossing Bridge under the effect of crosswinds, dynamic responses of vehicles and bridges under the action of crosswinds are analyzed based on the theory of wind-train-track-bridge coupling vibration analysis. Furthermore, the wind-vehicle speed threshold for safe driving on the bridge in strong wind environment is proposed according to the existing code evaluation standards. The results show that the horizontal and vertical dynamic responses of the main beam span increase with the increase of the incoming wind speed, especially the lateral displacement of the main girder changes significantly; the dynamic response of the train increases with the increase of vehicle speed, and the high wind speed environment will magnify the impact of vehicle speed on train safety. Compared with single-track traffic, the role of dual-track trains mainly affects the vertical displacement of the bridge, which is about 1.60 to 1.94 times that of the single-track effect at the design speed, and the dynamic response of the vehicle changes a little. In order to ensure the safety of the train on the bridge, the speed of the train on the bridge needs to be limited in case the average wind speed on the bridge surface is greater than 20 m/ s, and it is recommended to close traffic when the wind speed is greater than 30 m/s. [ABSTRACT FROM AUTHOR]

With high proportion of bridges in the intercity railway construction in China, standard beam bridges of common spans are mainly used and their technical economy has a great influence on the construction. In order to further improve the technical economy of common span bridges of intercity railway, the article summarizes the construction experiences of high-speed railway and intercity railway, and puts forward a layout of bridge deck, which is convenient for repair and maintenance, by optimizing the bridge deck layout according to the characteristics of intercity railway in the Pearl River Delta. By studying the mechanical performances of bridge decks of different line spacing, the section form of simply supported box beam suitable for the changing line spacing is proposed, which provides conditions for the standardized manufacturing and management of intercity rail transit bridges in the Pearl River Delta. By using high-strength prestressed steel strand and large tonnage anchorage device, optimizing web thickness and analyzing stress performance, material consumption and construction convenience with web thickness of 360 mm and 330 mm, the 360 mm web thickness of the optimized structure is determined. The optimized 32 m box beam can reduce the raw material cost by 39 000 yuan per span, and the comprehensive cost of 100-span double-track girder bridge can be reduced by 2.2%~4.5%. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design 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]

On May 22, 2021, a M7.4 earthquake occurred in Maduo County, Qinghai Province, which caused the damage of The No.1 and No.2 Yematan bridges in Maduo County. The main performance was that the longitudinal displacement of the bridge was too large, leading to the fall of the main beams of multiple spans and the damage of the bridge piers to varying degrees. According to the expert's appraisal, the intensity of earthquake influence exceeds the seismic design value of the bridge, and it is preliminarily concluded that the mechanism of the uniform beam falling damage is caused by the strong velocity pulse of the directional effect of near-fault ground motion. The investigation result of seismic impact intensity of the position of The Yematan bridge was IX .But the absence of strong vibration observation stations near the bridge and the lack of seismic records, were limited the study of the seismic response and damage mechanism of the Yematan bridge under the earthquake action. In addition, it is difficult to grasp the design parameters and damage of the bridge, and to estimate the bridge model accurately. Therefore, this paper intends to use another bridge with the same seismic fortification intensity through finite element program, using the response spectrum method as a reference, and fitting ground motion and pulse records to conduct the response time history analysis of the bridge structure, to indirectly reveal the seismic response characteristics and failure mechanism of the Bridge with Maduo earthquake. The calculated results show that the seismic response displacement and internal force of the bridge structure exceed the design value of rare earthquake, and the maximum response of one ground motion record is close to the design value of an extremely rare earthquake, which leads to the occurrence of earthquake damage or even damage of the bridge structure.

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University 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 Coal Science & Technology (0253-2336) is the property of Coal Science & 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 Harbin University of Science & Technology is the property of Journal of Harbin University of Science & 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.)