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Multi-tower cable-stayed bridge because of its unique structural features, beautiful appearance and economic cost to make it more and more popular in the construction of large-span cable-stayed bridge. But it also has its own structural defects, such as stiffness and long main beam, multi-tower cable-stayed bridge with cable-stayed bridge middle tower side anchor rope fixed cross-loaded in the middle, the middle level of the top of the tower displacement plus large, easy to cause the entire structure variable bit too large, thus affecting the linear and internal forces of the structure into a bridge, at the same time its tower multi long, the temperature effect is very significant. At present, domestic and foreign scholars multi-tower cable-stayed bridge stays in design theory, relatively little research issues related to its construction control, this paper bridge Jiashao as the engineering background, and how to improve the overall stiffness of multi-tower cable-stayed bridge reduce the long main beam temperature effects as well as the key issues in the construction control. The main contents and results are as follows: (1) According to the structural characteristics of the multi-tower cable-stayed bridge, from the stiffness of the structural members, the rational structure of the system and stiffening cable study how to improve the overall stiffness of the method of multi-tower cable-stayed bridge, and through cross in the main beam-beam tower beams consolidation, the main beam set a rigid anchor line three aspects of the problem of how to reduce the impact effect of the long main beam temperature, concluded for the same type of bridge design to provide a reference. (2) a reasonable cost multi-tower cable-stayed bridge state and reasonable construction of state determine the combined method, the basic idea of ??the method: given in advance to bridge state control parameters (the main beam, the main tower section stress value expected, the main Tata top side bit, cable-stayed stress and amplitude, etc.) or the permissible range, the use of dead load balance method initially for cable-stayed initial tension, based on the initial value of the given construction process and cable force established to consider construction The finite element model of the process, the use of suits iterative method notes the cable force, so that the conditions of the construction internal force the state to meet the design requirements, then the above steps based on the results considering the live load and the structural characteristics of the multi-tower cable-stayed bridge to bridge adjustment of status (mainly by adjusting the cable force, weights adjustment) to make it in the construction phase and the operational phase control parameter to the desired value within the allowable range, which determine a reasonable bridge state with reasonable construction state. The method was successfully abandoned the idea of ??reasonable completed bridge and reasonable construction states, which are determined to reduce the amount of work calculated at the same time does not exist is not closed. Expectations selection should be read in conjunction with the design specifications and the actual experience into account, to ensure reasonable expectations. (3) for multi-tower cable-stayed bridge many of the characteristics of Longkou, by changing the order of closure, demolition crane and temporary consolidation time, and Heavy Pressure Program, research on the Bridge of Jiashao a variety of different closure program, resulting conclusions can provide reference for the same type of bridge design and construction. (4) Bridge Jiashao at the background, the multi-tower cable-stayed bridge girder segment weight error, the beam stiffness Tasso error, concrete shrinkage and creep, cable force tension error parameter sensitivity analysis to identify the the construction process, the main design parameters and concluded with a certain reference value.
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