Study On The Balance About Tied Bar To The Pier Horizontal Thrust Of Concrete-Filled Steel Tube "Fly-Bird-Type" Arch Bridges

The structure of the middle load and concrete-filled steel tube(CFST) "Fly-bird-type" arch bridges,with flexible tied bar,uses tie bar to balance the arch structure horizontal thrust. Based on Yue Hai Bridge,the three-dimensional space model of the bridge is built.By analyzing the model many problems on construction phase of the CFST bridges are discussed in this paper,which including the tensioning force of the bar,the horizontal thrust on pier, bridges pier displacement and prestressing loss of the bar.In accordance with the feature of(CFST) "Fly-bird-type" arch bridges,the choices on ratio of rise to span,ballast weight on side span.We can analysis the process that how can through tensing the flexible tied bar in order to balance the horizontal pier's thrust.Deducing the horizontal pier's thrust when arch axis adapts to second-degree parabola and catenaries.Based on Yue Hai Bridge(a five-span tied arch bridge),the construction phase is divided into pouring concrete into the tube stage,hanging beams stage,the lay channel board stage and the completed bridge stage.The three-dimensional space model of the bridge is built. When design tensioning force is contrasted with horizontal thrust in every construction phases, the tensioning force of the bar can minis horizontal thrust on pier.It is propitious to the arch rib, because the horizontal thrust points at the middle span."M" method is used to calculate the displacement of bridges pier with the horizontal thrust and flexural moment,The result showed this effect that the tensioning force of the bar to pier displacement is fairly minor,when bridges pier volume was so big.Under the antecedent that the flexible tied bar is regard as an external prestressing cables calculating the prestressing loss,of which steel wire lavation and steering equipment are primary causes.The results also showed the effect that the prestressing loss of the bar to pier thrust and displacement is fairly minor,but the ratio of the prestressing loss to the tensioning force of the bar is 13.13 percent,so when the designed this problem which you haven't considered.