Profile Control And Analysis Of Composite Cable-Stayed Bridges By Cantilever Method

Cantilever construction method is generally used in large span composite girder cable-stayed bridges whose structure profile and internal forces in the completed bridge phase has an important relationship with the construction method being adopted, therefore strictly controlling the process of cantilever erection is very necessary. In order to make the profile upon completion state meet design requirements, correctly calculating the fabrication and installation profile and adjusting errors in the construction process are the key problems in profile control of composite cable-stayed bridge by cantilever method. This thesis is based on Guanhe bridge as the engineering background, which focuses on the research of calculating the fabrication profile and the fabrication error effects in final and construction stage using the finite element software NLABS. The main contents of this thesis are:(1) Introduced the concepts and methods of construction control in cable-stayed bridge; the development process, fundamental and engineering application of the geometry control method are detailed presented.(2) Introduced the calculation method of the non-stressed figuration of some key components in composite cable-stayed bridge, such as the cable, pylon and the girder. Discussed the differences and connects of the fabrication and installation profile, several calculation methods based on zero-initial-displacement and tangent-initial-displacement are also presented in detail.(3) Calculated the fabrication and installation profile, manufacturing dimension and the angle fabrication of the main steel girder in Guanhe bridge.(4) Effects of fabrication errors of the cable, pylon and the girder on final stage is researched detailedly. In conclusion, the cable-stayed bridge is more sensitive to the geometrical parameter errors based on the geometry control method.(5) Effects of fabrication errors of the cable and the steel girder on the main girder profile in construction stage and the fabrication error propagation properties are researched detailedly in this thesis. The girder profile error due to the cable length error, girder weight error and the angle fabrication error between main girder segments is typically convergent with the increase of cantilever length, while the girder profile error caused by the length fabrication error of main girder segments is typically divergent.