Research on Construction Control of Long-Span CFST Arch Bridge

Abstract

For an arch rib of concrete filled steel tube (CFST) erected by cable-stayed cantilever method, the construction control becomes increasingly difficult along with the erection of rib segments, owing to more system transformation, and higher degrees of static indeterminacy. First, for the problems usually occurred in the process of ribs erection, this paper presented a line-shape control principle that is “erecting higher, remaining stationary”. Secondly, based on analysis of the merits and demerits of common methods for cable forces calculation, and according to the principle of “remaining stationary”, a new calculation method for cable forces was proposed. At last, based on an X-style CFST railway arch bridge with a span of 360m, this paper compared the cable forces calculated by the new method with the actual tensioned forces, analyzed the variation of segments displacement in the process of erection, and discussed the influence of prearranged height on weld width. The control principle and the calculation method for cable forces presented in this paper have been proved effective, by the line-shape data measured after the closure of arch ribs, which may provide valuable reference for the construction control of similar CFST arch bridges.