Research On The Influence Of Post-Release Cable On The State Stress Of Concrete-Filled Steel Tube Arch Bridge

In recent years,the construction method of cable-hoisting cable-stayed fastening and hanging is widely used in the construction of long-span concrete-filled steel tubular arch bridges,it has an adverse effect on the stress of arch rib and reduces the efficiency of cross-section combination.In this paper,based on the large-and-small-well bridges,the influence of the back-released cables on the stress of long-span deck cfst arch bridges is studied,the main works are as follows:(1)the development and research status of cfst arch bridges at home and abroad are introduced,and the existing design and calculation theories of cfst arch bridges are summarized,it includes the calculation theory of material property of concrete filled steel tube,the calculation theory of section stiffness of Arch Rib,the calculation theory of temperature effect,the calculation theory of core concrete shrinkage and creep,etc.(2)aiming at the two schemes of cable-hoisting cable-stayed fastener-hanging construction,taking the large and small Jing Bridge as the engineering background and using the finite element software BDCMS,the calculation model of the whole construction process of cable-stayed fastener-hanging construction is established,the stress,displacement of the main arch and the stress and displacement in the course of construction are analyzed and compared.The results show that the stress of the arch rib steel tube can be improved to some extent and the safety reserve of the structure can be increased.(3)using the finite element software BDCMS to establish the whole calculation model including the cable-stayed fastening system,using the finite element software Midas/Civil to establish the separate calculation model of the fastening tower,and applying the cable forces of the fastening tower and the back cable obtained from the whole model to the top of the fastening tower,in this paper,the construction safety of the cable-stayed fastening system under the condition of the back-release fastening cable is checked during the concrete pouring.The safety feasibility of the back-uncoupling cable is analyzed.