| Concrete-filled steel tube arch bridge has become a prosperous force in the bridge field due to its high bearing capacity,rapid construction and its adaptability to the complex topography of high mountains and valleys.It has been widely applied and constructed on a large scale,and has become one of the main directions for the development of long-span Bridges.The combined effect of concrete-filled steel tube(CFST)is the precondition of its superiority.However,in practical engineering,the problem of separation of concrete-filled steel tube(CFST)arch rib generally exists,which directly affects the stress state and durability of the structure.Based on the analysis of concrete filled steel tube arch bridge in service environment,this paper analyzes the mechanism of the Separation and its influence on the internal force of arch structure,the temperature field of solar radiation and the time-varying effect of concrete.The main work of this paper is as follows:1.Based on the theory of concrete-filled steel tube calculation,at a 300 m mainspan concrete-filled steel tube arch bridge based on an engineering example,the combination of different numerical simulation method,the Midas/Civil is used to calculate the whole structure internal force and deflection under load,analysis of the internal force distribution of arch rib,summarizes the mechanical characteristics of arch structure,the contrast research theory simulation method and a unified differences of double-cell method;According to the overall analysis of the structure to identify the key components,the construction of the "steel tube-interface-concrete" fine microscopic model,analysis of concrete filled steel tube arch rib under the action of axial pressure,eccentric pressure of the interface and the degree of separation2.Based on ASHARE clear sky analysis model and transient heat conduction theory,the theory of solar radiation temperature field was clarified,and the finite element analysis process of sunshine temperature field of concrete-filled steel tube was clarified.Combined with APDL language of ANSYS,the simulation analysis of temperature field of concrete-filled steel tube under solar radiation was carried out,and the non-uniform distribution temperature field of concrete-filled steel tube was obtained.The model of thermal-mechanical coupling analysis was established to clarify the interface state between steel tube and core concrete under the action of non-uniform temperature field of solar radiation,and to reveal the non-uniform separation distribution rule.3.Based on the equivalent cooling method,the interface state of concrete-filled steel tubular(CFST)considering the time-varying effect of concrete is obtained.The ANSYS fine calculation model of "steel tube-interface-concrete" considering the time-varying effect of non-uniform temperature field-eccentric pressure-concrete is proposed.Under the guidance of theoretical analysis,a method for separation detection of concrete-filled steel tube(CFST)based on induced vibration was proposed,and a test for separation detection of arch ribs of engineering Bridges was carried out.4.Considering the material and geometric nonlinear,on the basis of concrete pavement is studied on the influence of the concrete-filled steel tube arch structure,analyzes the road.the impact on concrete-filled steel tube arch rib rigidity,and according to the working condition of the load-displacement curve,this paper discusses the typical load acting on the bearing capacity of the arch structure concrete,quantified the road.the impact on the structure performance of concrete-filled steel tube arch rib.The analysis shows that the bond between steel tube and concrete has an obvious influence on the bearing capacity of arch structure.Compared with the complete void,the live load coefficient decreases by 11% when the live load is full span,and by 13% when the live load is half span. |
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