Decision Method On Rational State Of Accomplishment And Research On Construction Control Of Long-Span Cable-Stayed Bridge

The long-span cable-stayed bridge,a kind of indeterminate flexible structure with many redundant degrees,consists of three basic members: girder, tower and cables. Its'inter forces are not unique under finished state. Weather the inter forces are reasonable decides the level of this design. If the structure and loading are fixed, we always can make out a set of cable forces to make some aims that response the force state of finished structure optimum under fixed structure and loadings.Most cable-stayed bridges are constructed by way of cantilever. During the construction, the shape and inner forces of structure change with the transformation of the structure and loadings accordingly. To be sure of the construction safety, to be convenient for the construction, to minimize the time of adjusting cable tension, it is very important for the designers to make sure that the working procedure is practical (the shape and inner stress of the structure is not too high to the criterion).Main contents of study:(1) How to make out the reasonable state of finished bridge and how to use in construction;(2) The effect of adjusting the cables tension to the girder forces during construction;(3)The effect of applying temporary dead-loading to the girder forces during construction.(4) Compare with the two result above and study them.Main conclusions:(1) A set of cable-forces can be found to meet the need of finished construction state.(2) Cable-forces adjusting and applying temporary dead-loading can improve the girder forces effectively during construction.(3) Applying dead-loading is more economical and convenient for construction.