Research On The Structural Performance Of Half-through Arch Beams Combined System Bridge

As the application of CFST(Concrete Filled Steel Tube)struetures to bridges has solved the problem of the application of high-strength material of arch bridge and the problem of the construction of arch bridge,two main bridge puzzles,arch bridge becomes much lighter and has stronger expressive force and the development of arch bridge is infused with fresh vitality.Therefore,CFST arch bridge has gained a booming opportunity in our country and meanwhile a large number of arch bridges have been constructed in our country.With wonderful architectural styles, through and half through arch bridges,are commonly favored in urban bridge design and construction so as to be the symbol of civic constructions.For the moment,they are still advancing on wider span and larger scale and their application region and scope are enlarged continually.Based on the structural characteristics of bridges with half-through arch beams under combined system of bridge, this paper analyzes the mechanical characteristic of CFST arch bridge. This thesis builds up a integrated and elaborate finite element model with Sap2000,a large-sacle finite element software,to discuss and analyze the CFST arch bridge's static behavior,shrinkage and creep, and the mechanical characteristic under lane load, the structural self-vibration characteristics, with some useful conclusions summaried.The results of study indicate that:(1) Concrete shrinkage and creep stress makes the steel arch cross-section increases an average of about 8%. Tied tension also increased, as the bridge state Department of shrinkage and creep to 3.1%increased drawbar pull, cross-boom of the crane in the displacement increases by 15%.(2) Prestress significantly improved the capacity of positive and negative moment area moment area of concrete slab cracking load, delayed the appearance of cracks.(3) The main modes of lateral vibration of a plane, the vertical-plane vibration and torsional vibration of space. Lateral vibration plane arch, the arch vertical plane vibration frequencies were 0.86Hz and 4.09Hz, the ratio between 1/4.76, indicating that the outer surface of the bridge span structure vibration is stronger than the vertical plane Vibration, which can have come forward to be weaker than the rigidity of plane stiffness.(4) The arch rib lateral braces for the existence of the structure of how much or not, and the influence of the transverse stiffness is bigger; Lateral brace the shaft bending has a little effect, because the cross ties do not provide overall vertical stiffness. Naked arch shaft bending frequency than the whole bridge corresponding higher frequencies 30%above, differences quite significant.(5) In vehicle loads of bridge structure dynamic analysis, upper bridge panel across in the same position static and dynamic loads compared longitudinal stress, the dynamic stress than static stress that dynamic effect for 1.19 force increases the bridge.The calculating results can offer the related technical parameters and basic data for the design certification,construction,health detection and maintenance in this kind bridge's working conditions.