Study On The Closure Of Cable-stayed Bridges Under The Influence Of Geometric Nonlinearity

Cable-stayed bridge is a complex high-order statically indeterminate structure system with common bearing capacity formed by anchoring cables at both ends to carriers such as towers,columns,beams and plates.Nowadays,construction of long-span cablestayed bridge is also in the process of rapid development,as a kind of highly coupled bridge design and construction,and from the design of the stress free state to design complete with stress state,before the application in the engineering construction stress free state of completion of the construction of a stress state again,always runs through formal pour down the problem,and the occurrence of this process there are always some deviation.Among them,geometric nonlinearity and process control of bridge construction have been widely concerned by academic circles.Although scholars at home and abroad have shown different conclusions and achievements,there is still a certain research space for the exploration of cable-stayed Bridges.For cable-stayed bridge,the main research thinking line composed of the five aspects in series,the first is the nonlinear factors and other factors(relative quantitative,construction material)problems cause into whether the state of bridge closure phenomenon,which in turn led to the optimization problem of state(also called cable force optimization problem),and this process can be through the analysis of the stress free state method as a medium for the internal force and linear state of concrete.In this paper,without considering the influence of construction error and the change of material elastic modulus and other influencing factors,the stress and displacement calculation analysis is carried out with the theoretical analysis of the closure of the reverse disassembly-fitting calculation as the core.This paper carries out the following related work:(1)Conduct relevant research and collation work.Based on the investigation of the current situation of cable-stayed bridge,the deformation of construction process,cablestayed adjustment and the analysis of cable-stayed bridge’s closure,this paper puts forward the complex influence of nonlinear factors and the necessity of further analysis.(2)The starting point is the simple force member--tension rod,tension string,etc.Under the linear assumption,the change from the stress-free state to the stress-free state is analyzed,and the reason why it does not satisfy the closure of the formal assembly is analyzed,and then the closure of the simple component is analyzed by modifying the Lagrangian coordinate system.The correlation convergence curve can be obtained by calculation and analysis.Then the closure of a cantilever beam under linear assumption and nonlinear factors is analyzed by combination,and the relation between convergence and geometric stiffness is studied based on the stress-free state method.Finally,a trial design cable-stayed bridge for analysis.(3)Based on the calculation of structural closure of the cable-stayed bridge in the trial design and without considering the influence factors such as the construction error and the change of material elastic modulus,the displacement increment approaches zero as the iterative step of the modified Lagrangian system increases in the analysis of the loading and unloading,and finally the state closure can be realized.When the bridge is reasonably completed,there is a hidden condition that the vertical component of the cable force should be balanced with the vertical force generated by other components.At this time,the analysis of each unit of the reverse demolition,there is no correlation does not conform to the actual situation,such as the occurrence of cable compression.