Construction Control Analysis Of Long-Span Prestressed Concrete Cable-Stayed Bridges

There are a large number of prestressed concrete cable-stayed bridges (i.e. P.C. Cable-stayed Bridges) in present China which have been completed or are being constructed. Long-span P.C. cable-stayed bridges are a type of bridges with great difficulty in design and construction. Construction control is one of key technologies in its design and construction, which guarantees the security of constructing structures and the curve of the stiffening girders so as to meet the requirement for the completed bridge. Therefore it is very necessary and valuable to research the construction control analysis of long-span P.C. cable-stayed bridges.The dissertation proposed a self-adaptive construction control analysis method which is used in the design and construction analysis of long-span P.C. cable-stayed bridges. In the structural computation, the geometric nonlinearity and the effect of the creep & shrinkage of concrete are considered. The ameliorated continuous rigid-support beam method is proposed to analyze the rational completed state. The forward-iteration method is utilized to analyze the rational construction state. The parameter check-identification method based on the least squares method is proposed for parameter error identification. The grey forecast model with residual error correction is used to forecast parameter errors. Cable tension adjustment is analyzed based on the concept of the minimized complementary energy of internal force differences between the design state and the state after tension adjustment.In the ameliorated continuous rigid-support beam method, moments of the continuous rigid-support beam are computed by the three moment procedure. Then, with the moments on the beam's control sections, the appointed moments on the towers' ones and the reactions on the piers and abutments as the objective, the least squares method is used to analyze tension adjustment. With the cable forces from the continuous rigid-support beam method as the initial ones, the iteration procedure is carried out until the convergence to an optimized reasonable completed bridge state. The parameter check-identification method based on the least squares method makes parameter error identification more efficient. In every construction stage, the control variables of the stage and the previous one are surveyed. Then, the least squares method is used to identify structural parameter errors of the stage such as the weight density of beam members, cable tensions, the stiffness of beam and tower elements and creep & shrinkage coefficients, etc. At the same time, the structural parameter errors of the previous stage are checked. The grey forecast model with residual error correction is used to forecast parameter errors, which improves the forecast precision.