Research On Force Transfer Mechanism And Mechanical Performance Of Cable Tower Anchorage Zone Of Long Span Steel Tower Cable Stayed Bridge

The Cable Tower Anchorage Zone is the key structure to transfer the external load and self weight of the bridge superstructure to the cable tower.It bears strong concentrated load.The stress and structure are complex,which is usually the difficulty of control design and construction.At present,the number of steel tower cable-stayed bridges built in China is small,and the research on the cable tower anchorage zone of long-span steel tower cable-stayed bridge is not enough.Therefore,it is necessary to study the force transfer mechanism and mechanical properties of the anchorage zone of steel tower cable-stayed bridge.Through theoretical analysis and finite element numerical simulation,this paper studies the force transfer mechanism and actual stress characteristics of the cable tower anchorage zone of a proposed long-span steel tower cable-stayed bridge.The research content of this paper mainly includes the following aspects:(1)This paper summarizes the development status of existing long-span steel tower cable-stayed bridges at home and abroad,summarizes the development process and structural characteristics of the cable tower anchorage zone of steel tower cable-stayed bridges,as well as some problems to be solved in the steel anchor box cable tower anchorage system.(2)The macro spatial frame model of long-span steel tower cable-stayed bridge is established by using the finite element software MIDAS,and the mechanical properties of the whole bridge model tower are analyzed.At the same time,based on this,the method of selecting the anchorage zone of typical cable tower and its most unfavorable stress mode are given.(3)Due to the complex structure of the Tower Anchorage Zone of the steel bridge of the cable-stayed bridge and the unclear local mechanical behavior of the structure,the threedimensional fine entity local analysis model of the Tower Anchorage Zone is established by using the finite element software ABAQUS,and the effects of the model parameters,element types,grid division,model loading,model boundary and constraints of the finite element model on the finite element analysis results of the Tower Anchorage Zone are analyzed in detail.In addition,the mechanical characteristics of the structure are analyzed in detail by combining the whole bridge model and the local model of Cable Tower Anchorage Zone.(4)Based on the local analysis model of Cable Tower Anchorage Zone,this paper expounds the force transmission mechanism of stay cable force in each plate of steel anchor box in detail,and quantitatively expounds the force transmission of cable force in the structure of steel anchor box by theoretically calculating the stress of welds between plates.In addition,the force flow analysis method is used to study the force transmission mechanism of the anchor box cable tower anchorage zone,and the visual analysis of the force transmission mechanism of the cable tower anchorage zone is carried out through MATLAB software to reveal the force transmission mechanism of the cable tower anchorage zone as a whole.(5)Based on the analysis of the mechanical characteristics of the anchorage zone of steel bridge tower,the suggestions for optimizing the mechanical properties of the anchorage zone of steel bridge tower are given.Combined with the specifications,the specific method for quantitatively evaluating the safety performance of the anchorage zone of steel bridge tower is put forward.