Multi-span Cable Stayed Bridge Construction Control Of The Key Issues

Multi-tower cable-stayed bridge because of its unique structural features, beautiful appearance and the economic cost make it in the long span cable-stayed bridge construction more and more popular. But it also has its own structural defects, such as rigidity and long main beams, multi-tower cable-stayed bridge in comparison with the normal side of the middle tower cable is not fixed, cross-loaded in the middle, the middle of top horizontal displacement increase, the entire structure easily lead to excessive deflection, thus affecting the structure into the bridge line and internal forces, while its tower and more with long, very significant effect of temperature. At present, scholars study of multi-tower cable-stayed bridge stays in the design theory, construction control issues related to their relatively small study, This article with Jiashao bridge engineering as background, on how to improve the overall stiffness of multi-tower cable-stayed bridge to reduce the length of main beam temperature as well as construction control of the key issues. The main contents and results are as follows:(1) According to the structural characteristics of multi-tower cable-stayed bridge, Have researched the methods that how to improve the overall stiffness of multi-tower cable-stayed bridge from the structural elements, reasonable structure and the stiffening cable system and the other respects, and by setting the girder cross-link beam, tower Girder, the main beam setting rigid hinge studied three aspects of how to reduce the length of main beam temperature effect of the problem, the conclusion can provide reference for the same type of bridge design.(2) Proposed a multi-tower cable-stayed bridge into a state of reasonable and rational construction of the state determine the combined approach, the basic idea of this method are: Prior state of a given control parameter into the bridge (the main beam, the main stress of tower cross section, the main tower top deviation, cable stress and amplitude, etc.) or allow the expected range of dead load ,useing the method of load balance to determine the initial tensile force cable, based on the predetermined construction and cable tension to consider the construction process to establish the finite element model, useing the forward-teration method to adjustment the initial cable tension, it conditions the construction of internal force can meet the design requirements, and then step over based on the results considering the live load and the structure of multi-tower cable-stayed bridge into the characteristics of the adjustment of status (mainly by adjusting the cable tension, re-adjust the pressure), so that in each stage of the construction phase and operation parameters under control meet expectations, or in the allowable range, which also determine a reasonable and rational state of bridge construction status. This method was successfully abandoned the previous state of reasonable and rational construction of the bridge into the state of the idea were determined to reduce the computational work. Expectations should be combined with the selection of design and practical experience into account, to ensure that expectations are rational.(3) There are many multi-tower cable-stayed bridge for the Closure of the characteristics of this closure by changing the order of removal of the crane and the provisional time and the pressure of re-consolidation program, the Jiashao bridge closure for a number of different programs of study, conclusions can be the same type of bridge design and construction of reference.(4) Jiashao Bridge to the background section of the multi-tower cable-stayed bridge girder weight error, the error beam stiffness Tasso, concrete shrinkage and creep, cable tension force error, and other aspects of the parameter sensitivity analysis to identify the process of its construction The main design parameters and concluded with a certain reference value.