Optimal Research Of Prestressing Tendons In Long-Span PC Continuous Rigid Frame Bridge

Continuous Rigid Frame Bridge is one of the main form of the large-span bridges. It has some strongpoint such as large span, comfortable driving and economic cost. Now large span Continuous Rigid Frame Bridge is constructed one section by one section in the way of cantilever. In this paper, base on the cantilevered construction characteristics of continuous rigid frame bridge, one optimization method of prestressing tendon was presented. Its design concept is based on the construction phase and the cantilever bridge on T-stage moment equilibrium configuration prestressed beams, Analysing and investigating the problem of the curved web beam prestressing tensons and how to set up a reasonable amount of continuous prestressing teasons in bottom plate of box section.Beased on a Continuous Rigid Frame Bridge in Xiaowan Hydropower Station in Yunnan Province, considing constrction process and shrinkage and creep of concrete, analysis the anchor position of the curved web beam prestressing tendon in the largest cantilever beam and the construction phase, the result is that the large-span continuous rigid frame bridge must be set up the curved web beam prestressing tendon.The best location for the anchor of the curved web beam prestressing tendon is the box beamcentroid or half height of the box beam;Seting up reasonable amount ofprestressing tendons in bottom plate of box in middle span so as to forcingformance of bridge is reasonable. These obtained conclustion will give some references for practical prestressing tendons designing of continous rigid frame bridges.