Research On Geometric Nonlinear Cable Force Adjustment Algorithm Based On Specified Stress

The cable-stayed bridge structure is mainly composed of three parts:tower,cable and beam,which belongs to high-order statically indeterminate structure.For cable load-bearing system structure,the nonlinear problem of cable-stayed bridge structure is more prominent.Therefore,geometric nonlinearity should be considered in cable force adjustment of cable-stayed Bridges.In addition,the cable-stayed bridge structure has high requirements on the line shape and internal force of the bridge.When it reaches the state of reasonable bridge,it should be able to meet the relevant requirements of cable force,line shape and internal force.The outstanding feature of the cable-stayed bridge structure is that it can change the structural stress state and line shape through cable force adjustment,and quickly and effectively determine a set of economical and reasonable cable-stayed bridge cable force adjustment values,which can effectively reduce the construction period and save construction costs.Therefore,it is necessary to study the cable tension adjustment algorithm of cable-stayed bridges.In this paper,the second cable force adjustment algorithm of the cable-stayed bridge is completed.The core content mainly includes the following three parts:(1)The basic theory of T.L column method,U.L column method and CR column method in geometric nonlinear analysis is expounded.The tangential stiffness matrix of truss element and beam element is obtained by co-rotation coordinate method(CR column method).In this way,the adverse effects caused by nonlinear behavior in the cable-stayed bridge structure are considered.The nonlinear solution program is compiled by using VC++language.The nonlinear program is tested by numerical examples.The results show that the program is used to calculate the non-linear program.Linear problems can achieve higher accuracy requirements and are superior to ABAQUS software in computing truss-like nonlinear problems.(2)The cable unit used in this paper is derived from the ordinary truss unit,and the inelastic shrinkage and temperature change are added to the ordinary truss unit to simulate the cable unit in the cable-stayed bridge structure;Based on the specified stress balance equation,the cable element is derived and introduced in detail,and the cable force adjustment program is written by combining the nonlinear program and the cable element stiffness matrix.A new idea of adjusting the secondary cable force after the cable-stayed bridge is completed under the condition of stress or internal force is specified.(3)Design a numerical example of the cable-stayed bridge model with relevant literature and specifications,run the programmed program to obtain the corresponding numerical solution(adjustment value)of each cable,and adjust the cable force of the cable-stayed bridge model,and use the ABAQUS software to The numerical solution(adjustment value)is verified.The results show that the adjustment value of all cables of the cable-stayed bridge can be solved once by using the cable force adjustment method.It is not necessary to carry out repeated calculation and cable force on the cable.The adjustment does not have to consider the interaction between the tensioning sequence of the cable;in addition,the numerical solution(adjustment value)calculated by the cable tension adjustment program of the cable-stayed bridge prepared in this paper has higher precision and is adjusted according to the numerical solution(adjustment value).The rear cable force value is in good agreement with the reasonable bridge cable force design value.