Study On Mechanical Characteristics Of Combined Bridge Of V-Shaped Pier Rigid-Frame And Arch Structure

Through the connection of slant legs of main span of V-shaped pier continuous rigid-frame and arch springings of concrete-filled steel tube arch ,the combined bridge of V-shaped pier continuous rigid-frame and arch structure is formed. This bridge type has the feature that arch load together with V-shaped pier continuous rigid-frame,which is different from general beam-arch combination bridge. Through the engineering example of Xiaolan Channel super bridge, several questions are investigated in this thesis.1,Static analysis in construction stage and using stage of Xiaolan Channel super bridge is proceeded by finite element of plane bar system method. The analysis results indicate that:a) In construction stage,the stress of the bottom of V-shaped piers is very sensitive to demolition of temporary supports and change of the structure system.b) The bottom of V-shaped piers are in relatively adverse state before the main span closurd,so the stress of the piers must be monitored before the main span closurd.c) In using stage,the maximum positive moment and negative moment of main girder are greatly decreased because of shrinkage and creep of concrete.2,Local stress analysis of arch-pier-beam fixed joint of Xiaolan bridge is maked by solid finite element method. The analysis results indicate that:a) Because of the enforcement effect of oblique diaphragm,fiexural rigidity of the box gieder is increased in this segment, the principal compressive stress of the region with oblique diaphragm is lower than the region without it.b)Most region of the arch-pier-beam fixed joint is in three-directional pressure state.construction of the bridge is reasonable designed,which is enough to resist the principal compressive stress and tensile press in the worst condition.3,Seismic response analysis of Xiaolan bridge is maked by finite element of spatial bar system method. The analysis results indicate that:a) Vertical seismic motion had significant effect on seismic response,so in the seismic analysis of this bridge,the associated effects of horizonal seismic motion and vertical seismic motion must be considered.b) Input with two different seismic waves which have the same acceleration peak and the same period, the difference of the response of the bridge is small.c)Reponse spectum method is not suitable for seismic analysis of Xiaolan bridge ,because it belongs to large span combined bridge.4,Arch effect and beam-arch associated effect are analysised in this thesis,the influence of slant leg rigidity to static characteristics of the bridge is also investigated. It is pointed out that thichness of slant legs in Xiaolan bridge is controlled by stress in construction stage. Finally, the influence of secondary dead load and pile-soil-structure interaction to dynamic characteristics and seismic response of the bridge are analysised.