Research On The Key Issues Of Construction Control Of Red River Bridge

Composite beam cable stayed bridge has the advantage of lighter deck,excellent stiffness and stability. According to the development of cable stayed bridge in recent years, more and more long-span cable-stayed bridges use the form of composite beam. This paper is written under the ground of Red River Bridge, and several key issues of construction control of this bridge is studied. The main study contents are as follows:(1)Cable force calculation of cable stayed bridge: combined with minimum bending energy method and using influence matrix, considering the moment, stress, displacement of each structural member, setting feasible region, adjusting the cable force of cable stayed bridge, in the end, a set of reasonable cable force is obtained.(2)Calculation of initial cable force and unstressed cable length: dress difference iteration method is used in order to get accurate initial cable force of Red River Bridge. When setting the error is within the range of 3%, 4 iterations could reach the requirements, the convergence is fast. Using catenary formula to calculate the unstressed cable length. According to coupling relationship between horizontal component and cable shape, iterate the horizontal force, and ultimately determine the unstressed length of cable. According to the actual length of the work area, plus cable-stayed unstressed cable length, the length of each cutting the cable is given.(3) Linear Control of Red River Bridge: The three kinds of linear of cable-stayed bridge were discussed, Concept and internal connection of three kinds of linear is cleared, and the process of solving fabrication geometry is emphatically discussed. The accuracy of the calculation of fabrication geometry directly affects the alignment of the bridge, in this paper, the fabrication geometry is calculated based on the unstressed state method. Steel beam of Red River Bridge use bolt connection, fabrication geometry is realized by changing the position of the bolt hole, while the steel beam produced in the factory only need to make the corresponding axial compensation. For this type of structure, The dominant idea of solving the fabrication geometry is still unchanged, the bolt hole position can be determined according to the unstressed angle.(4) Temperature control of mass concrete pile cap: Large volume concrete hydration heat is a problem that must be paid attention to during construction. Through the establishment of a reasonable finite element model the concrete hydration heat was calculated, and guide the construction. Starting with the control of concrete mix proportion, reasonable arrangement of pipe cooling, construction, and other aspects of heat preservation measures to ensure the quality of the construction of the platform.