| Composite beam cable-stayed bridge is a new bridge type started late in china.The standard composite beam is composed of steel beam lattice and concrete bridge deck above it through shear keys into an entity to bear deck load,and the steel beam lattice is made up of steel girder,steel beams and small longitudinal beams.Because of its structural characteristics of more block elements, the construction control of composite beams is particularly important when cantilevered assembling.Firstly, based on basic theory and current construction techonology, this thesis briefly discussed the reason for using geometric control method based on linear control laws in composite beam consruction control, and introduced its theoretical basis and practical feasibility.Secondly, based on the construction control of Jiangjin Guanyinyan Yangtze Bridge, this thesis analysed the sensitivity of this bridge.According to the analysis, we can find the structural parameters to which the beam linear is highly sensitive, they were beam weight and cable manufacturing length.Finally, according to measured elevation of girder in construction site, above sensitive parameters can be amended by the least squares method, we can re-take them to the calculation model. So the parameters of calculation model was closer to actual value,and we inspected the theoretical value and the actual value error in following beams computation,proving that the control computation accuracy can be better guaranteed by the computation model whose parameters were adjusted by the least squares method. And then, according to measured elevation and cable force, we used the gray theory to establish GM(1,1) model in order to forecast the following beam elevation and cable force in every operating mode and examined the actual value and the predicted value error. We also used the gray theory in the following beams control computation and obtained good control effect, preparing for the final combination.
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