Key Technology Research On Steel Tower Construction Of Large Span Single Plane Cable-stayed Bridge With Composite Girder

Whereas the large span steel concrete composite deck cable-stayed bridge has been developed rapidly in China due to its unique structure and beautiful shape. The background of the proposed subject research is based on the world-known ongoing Hongkong-Zhuhai-Macau Seacrossing Bridge project which is famous for its largest investment budget in the world. It is intended to execute special construction technology research based on the key issues in relation to the superstructure of large span steel concrete composite girder cable stay bridge based on the technical and structural characteristics. In particular, due to the limitation of aviation navigation, the main steel tower of main bridge for Hongkong-Zhuhai-Macau Seacrossing Bridge could not be constructed by means of traditional segmental assembling method, it is proposed to innovatively adopt combined proposal of “Large Block Lifting + Vertical Rotation”.By means of structural analysis, it is proposed to carry out model analysis for all construction technology. By taking advantage of FEM software MIDAS/CIVIL to establish model, in accordance with load combination, it is intended to verify the stress and geometry of main construction temporary structure during the construction process of main tower so as to provide the simulation analysis for stress, temperature variation, vertical rotation etc. during construction of main tower for providing reference and basis for construction of cable tower. Furthermore, in order to specify the stressing state of vertical rotation of main tower, it is proposed to use MIDAS software to establish model to carry out stressing analysis and calculation for vertical rotation frame and steel tower. Steel tower and curved ribs will be simulated by beam element, pressing rod of vertical rotation frame will be simulated by beam element and further the jointing ends of steel tower will be released for rotational freedom degrees. Connecting brace of pressing rods will be simulated by beam element and pressing rods will be simulated by rod element. Later it is proposed to use the calculating results to compare with the construction technology as originally adopted in the design so as to provide part of reference for the design and construction of large span cable stayed bridge tower of similar type.At the same time, in order to assure that the alignment and geometry of main tower of main bridge for Hong Kong – Zhuhai – Macau Seacrossing Bridge could satisfy with design requiremen ts, it is proposed to strictly control the construction process of steel tower based on the precise simulation analysis and calculation and in combination with on-field actual surveying data. By adopting effectively controlling and adjusting the structural geometry, cable force and stress etc. during construction period to ensure that the alignment, cable force and stress of steel tower during vertical rotation and after completion will satisfy with design targets.