Calculation Methods For Cable Curve Of Suspension Bridge

Suspension bridge is a composite system made up of cable, tower, stiff girder and suspender. Because the main cable is tensioned, the material is utilized efficiently. It has become the first choice for the long-span bridges. Suspension bridge especially the long-span suspension bridge's flexible feature causes its linear to be susceptible to the construction conditions, temporary facilities and the impact of environmental temperature. So the cable-shaped accurate calculation is the key point of suspension bridge's construction control.This also was one of the major reasons that construction control study of suspension bridge in recent years has become a hot.The cable is the main supporting component in the system. Its shape in the bridge's completion state is the key controlling factor of structure design, calculation and guiding construction. It is necessary to establish the cable shape's computation method complying with the actually situation. On one hand, the bridge structure analysis must depend on precise configuration of the bridge's completion state,main cable shape directly affect force distribution of the overall structure;On the other hand, the main cable configuration will determine its own unstressed cable length, crane boom location and the unstressed crane length, these parameters are essential to design and construction control.This paper introduced several analytical methods of the cable linear calculation in detail, such as parabolic law, the traditional sub-catenary, parameter equation, the section line method and so on,and also raised its deduced catenary method, according to the method this paper derived the corresponding procedures and caculated, and compared calculation result with the literature.The results show that the catenary equation this paper deduced is right, and established a reasonable formula for the amendment, making iterative fast convergence,calculation simple, calculation results accurate, can be used for preliminary design of the suspension bridge.