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Nanjing, China

Tong L.-H.,China Railway Major Bridge Engineering Group Co. | Wang L.,The 2nd Engineering Co.
Bridge Construction

The main bridge of Anqing Changjiang River Railway Bridge is a steel truss girder cable-stayed bridge with double pylons and triple cable planes. The steel truss girder of the bridge is designed as the parallel truss type of N-shape and is composed of three main trusses. The girder of the main bridge in the areas without stay cables has 12 panels, totally weighing 6 041.5 t. The panels of the girder were installed by the piece-by-piece assembling method, of which the 8 panels between the Pier No.6 and Pier No.7 were installed on staging and the 4 panels between the Pier No.6 and Pier No.5 were installed by the cantilever method. The piers of the staging were arranged at the locations corresponding to each panel point of the girder and totally 7 arrays of the temporary piers were arranged. In each array of the piers, there were 6 steel pipe piles and the piles were driven in and extended by the vibrating hammer. The panels of the girder were lifted and installed and the erection of the girder was completed by the repeated utilization of the 200 t capacity floating crane alternatively placed at the downstream and upstream sides. The erection of the steel truss girder of the bridge was completed on October 15, 2011 and the inspection of the erection proved that the geometric shapes and stress of the girder in the areas without stay cables could accord with the design requirements. Source

Sun M.,The 2nd Engineering Co.
Modern Tunnelling Technology

The exit section (510 m) of the Xiuning tunnel on the rebuilt Chengdu-Kunming railway, passing under the Longtan reservoir, is located in the Luoci-Yimen fault zone. The stratum is composed of rare water-rich mylonite with a classification of grade VI. After excavation, mylonite in the form of plastic flow can easily cause mud gushing and collapse, resulting in large deformation of the primary lining. To pass through this stratum safely and quickly, the deformation of the surrounding rock has to be controlled. Based on a water stability test of mylonite shear strength, this paper presents a support method for this section, namely, full-face pre-grouting with pipe-roof support. Using numerical simulation and deformation monitoring of the surrounding rock and lining structure, it was proven that full-face pre-grouting can effectively achieve water blocking, water squeezing, drainage consolidation and rock strength improvement; pipe-roof pre-support and three-bench seven-step excavation can effectively control rock deformation, ensuring construction safety. Source

Li K.,The 2nd Engineering Co.
Advances in Energy, Environment and Materials Science - Proceedings of the International Conference on Energy, Environment and Materials Science, EEMS 2015

This article establishes a nonlinear finite element model based on the general finite element method, and simulates the stress of the reinforced rust caused by the reinforced concrete in the arch foot of the Xixihe bridge. Based on the finite element numerical analysis, the calculation method of the corrosion rate of reinforced concrete corroded reinforcement is presented. Numerical calculation and analysis, including the concrete component angle of reinforcement corrosion and central reinforcement corrosion of uniform corrosion expansion force of concrete member, based on previous reinforcement corrosion distribution theory analysis results, combines with the results of the numerical analysis of the corrosion expansion force, to calculate the arch foot concrete cover cracking moment of steel corrosion rate, predict the Xixihe bridge arch foot concrete protective layer cracking time, and provide the reference for the design. © 2016 Taylor & Francis Group, London. Source

The usage amount of concrete for the in-water pier works of the Hutong Changjiang River Bridge is 1325000 m3. To determine the supply systems of such a huge amount of the concrete for construction of the pier works, the general plans of the concrete mixing plants were made in the light of the riverbed elevation, the specific required amount of the concrete and also in consideration of the shallow and deep water areas. Through comparison of the supply capacity, construction difficulties, construction periods and construction cost of the two schemes of the steel platform mixing plant and hydraulic reclamation island mixing plant, it was finally determined that in the shallow water area, a reclamation island mixing plant should be applied. The height of the island would be about 6.1 m and at the outside of the surrounding dyke, a ring of the 1 m high and 0.3 m thick cast-in-situ concrete retaining wall would be arranged. In the deep water area, the steel platform mixing plants (made up of the steel pipe piles+pile top distribution beams+Bailey truss beams+steel floor systems) should be applied. For the reclamation island mixing plant in the shallow water, the surrounding dyke would be constructed first, the reclamation sand inside the cofferdam and the side slope protection outside the cofferdam would be then constructed. The rubble stone base would be laid and the concrete would be finally cast to form a platform. For the steel platform mixing plants, the steel pipe piles would be set and driven first and the bracing systems connecting the piles, the pile top distribution beams, platform main beams and the floor systems would be then successively constructed. © 2015, Journal Press, China Railway Bridge Science. All right reserved. Source

Yang X.-J.,Tongji University | Hu Z.-D.,Tongji University | Liang J.,Marine Design and Research Institute of China | Jia H.-R.,The 2nd Engineering Co.
Dongbei Daxue Xuebao/Journal of Northeastern University

Based on the scattering theory of elastic waves, the scattering of SH wave and the dynamic stress concentration around circular tunnel with lining were investigated by employing the wave function expansion and mirror methods. The analytical solution of the problem, which was taken as a group of unlimited algebraic equations, was derived, and the numerical solution of the dynamic stress concentration factor around the lining was given. The effects of the shear elasticity of the surrounding rock and the lining, together with the wave number on the dynamic stress concentration factors were analyzed. It is shown that the shear elasticity of the surrounding rock and the wave number are factors that influence dynamic stress concentration, which may provide important theoretical basis for the earthquake evaluation of lining. Source

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