Study Of Mechanical Behavior Of Arch Rib Of Long-span CFST Tied-arch Bridges

In the architecture of CFST, steel tube has constraints on the concrete. In thisarchitecture, the steel and concrete make up for the shortcomings of each other, give full playto their respective advantages. In recent years, CFST has been widely used in the constructionof CFST arch bridges. In the tied-arch bridge of CFST, the boom transfers the load to the rib,rib finally transfers this load to the stand, most of the load is transferred to the support by rib.Rib directly affects the safety performance of the bridge, so the study the mechanicalbehavior of arch rib is very important.In this thesis, As a project background to the Urumqi River Bridge, the mechanicalproperties of CFST tied-arch bridge were studied, mainly to complete the following tasks:Describes the construction process as well as the CFST bridge performance compressionmembers, a detailed theoretical analysis of the dumbbell-type CFST arch mechanicalcharacteristics of the construction process. Using the software of finite element analysisnamed Midas/Civil establish a full-bridge model of arch ribs in various stages of construction,the bridge phase into the operational phase of the force as well as a detailed analysis,summarizes rib force law. In a final stage, arch rib stress range-(65~106) MPa, rib steel bear56%to58%of the total internal forces, the next chord bear20%to25%,assume19%of thechord to22%.Operational phase, rib Pipe Stress-(112~190) MPa. The theoretical analysis iscoMPared with the measured values, pipe stress analysis results of bias because of concretefluid pressure.It analyzes the effects of different order of the pouring of concrete arch rib force,then, itfinds that the internal force of each section is unchanged. The basis for determining theoptimal perfusion sequence is positive and negative bending moment rib. If rib by positivebending moment, the first infusion upper chord.If rib by negative moment, the first infusionlower chord.It analyzes the effect on the force of different Rib stent in removal time, gets aconclusion that after the first infusion stand Rib demolition order is more reasonable, its steelstress is reduced from10%to19%, the upper and lower chord concrete stress increases12%to30%, Rib steel bears46%to48%of the total internal forces, the lower chord bear24%to27%, the upper chord bear25%to28%.