| Recently, the structure of concrete filled steel tube arch bridge has been rapid development in the highway bridge construction in China, Hejiang bridge as the representative, span520meters called the biggest span concrete-filled steel tube arch bridge, concrete-filled steel tube is superior to many excellent mechanical performance and convenient construction, composite materials and concrete filled steel tube this became a lot of people in the industry construction of large span arch bridge of choice. Although the concrete-filled steel tube arch bridge in China, built many, but we for CFST arch bridge research is not perfect, on the stability of this, in the past many scholars are the stability of long span CFST arch bridge under the action of load of the structure, in fact, this is far from enough, because the construction process of concrete filled steel tube is very complex, the construction and the bridge is also associated with, only to ensure that the bridge can party can ensure the whole bridge construction and operation stability in the construction process, so the stability of the construction process of large span CFST arch bridge is analyzed, the main work is as follows:1.Using midas/civil to simulate different transverse bracing structure in the form of arch structure in different forms (hingeless arch, and two hinge arch) of arch rib in the stability of hollow steel tube under the condition, and the hinged arch and ratio of two hinged arch were no analysis of the obtained results and theoretical derivation, the final calculation just for lateral stiffness can satisfy the buckling lateral stability calculation is required to conclude theory, to compute the spatial stability must calculate the space stability of the structure by using finite element software;2.This paper uses is the unified theory of concrete filled steel tube and to become a kind of composite material, and the general formula of round steel pipe concrete constitutive relationship proposed by Professor Han Linhai, the string according to the concrete filled steel tube Zhaohua Jialing River bridge arch steel frame of the pipe size and material strength calculate the main chord in this model to use the pipe cast-in-place concrete after the formation of concrete filled steel tubular composite materials as a constitutive relation of unity;3.This paper adopts Zhaohua Jialing River Bridge as the engineering background, the constitutive relation of unified theory of concrete filled steel tube, the large-scale general finite element software ANSYS as a platform, using beam188to establish the calculation model of concrete filled steel tube unit much chord tube stiffness skeleton arch rib, and for the main chord arch rib tube presents4different concrete pouring scheme, and through ANSYS linear buckling analysis to select the best perfusion solution, then each condition for optimum analysis of geometric and material nonlinear, the buckling safety factor structure in nonlinear state, and the stability of the state structure are compared to a conclusion;4.Because the steel pipe concrete pouring to form a unity of this process is a very complex process, based on the simulation of each main chord tube cast-in-place concrete are simplified into "before","in","after" three processes, the so-called "before" refers to an empty steel tube state, this time using the constitutive relation of steel; the so-called "" refers to the pouring of concrete, and concrete is not enhanced condensation, so concrete as external loads in the air pipe unit, and the air pipe used or steel constitutive relationship; the so-called "post" is refers to the concrete has been strengthened and steel bonded into a whole to form a unity, and material properties used in the software is the constitutive relation and the bulk density of the new unified body material. |
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