Girder Stress Control And Closure Technique In Construction Period Of Long-Span Hybrid Girder Cable-Stayed Bridges

There are two cases that maybe appear on the construction of long-span cable-stayed bridges. As we know, the erection procedure of steel box girder is always built by the method of cantilever construction. For long-span cable-stayed bridges, when the main beam under the condition of long cantilever, the stress of the girder will be very large, and even more it may be overrun. On the closure construction of cable-stayed bridges, there would be an ideal temperature, which is called datum temperature. But in the actual construction process, there will be environment temperature is not consistent with the datum temperature in the time of closure construction, then the width of the closure does not match the size of the design width, so construction state is not an ideal situation, that would be affect construction.Taking the construction of Edong Yangtze River Bridge for background, and in accordance with the theory of geometry control, this thesis analyzes the situation appears in the construction of the large-span cable-stayed bridges, and studies control measures for girder stress and geometric closure technology of long-span hybrid girder cable-stayed bridges. The main works are as follows:(1)The current construction situation of cable-stayed bridge is firstly depicted, and the history on the development of control methods for the construction of cable-stayed bridges is described secondly. Then introduced the main contents of this thesis.(2)The thesis elaborates the theory of geometric control method in detail, and then deduces formula of construction state and final state for beam structure and cable-stayed structure. And then explains features of the geometric control method.(3) Based on the theory of the geometric control method, the stress control method of the steel girder is analyzed under the state of long cantilever. And the thesis introduces that how to use the method in actual projects, such as Edong Yangtze River Bridge.(4) In according to the theory of the geometric control method, the factors that should be controlled are studied in geometry closure method of cable-stayed bridges, and then introduces that how to use the method in actual projects, here the thesis takes the Edong Yangtze River Bridge for example.