| Main cable for suspension bridge is the main bearing structure of the bridge, due to suspension bridge spanning capacity big, beautiful modelling, economic and reasonable, so it is the bridge of choice for a long-span bridge. To inch beach Yangtze river bridge construction monitoring accurately, but also according to the characteristics of the suspension bridge main cable has strong geometric nonlinearity, in this paper, the research object, focusing on the main cables of suspension Bridges and the inch beach under construction is the Yangtze river bridge as the engineering background, calculation and analysis, discusses the calculation theory of suspension bridge main cable linear and geometric nonlinear finite element theory, and explores some practical analysis method to calculate. In this paper, the main work done is as follows:First, this paper introduces the suspension bridge of traditional parabola theory, approximate segmental catenary(ignoring main cable set weight degree change) caused by the elastic elongation and precise segmental catenary(weight of main cable caused by the elastic elongation set degree change). Using MATLAB to the three theories respectively the corresponding calculation program, and the beach Yangtze river bridge are calculated, thus the calculation results of three kinds of theories on the basis of the comparison and error analysis.Second, saddle position calculation method is introduced, the basic equations of calculating the saddle position to closely mathematical deduction, when using the basic equations to calculate all the known parameters can be directly into the numerical solution of are; Using MATLAB compiled the cable saddle position calculation module, Yangtze river bridge north and south respectively to inch beach analytic calculation, the main cable saddle and compared with the given parameters on the design drawings, good results; Under the theory of two vertices defined cable saddle position calculation results are also analyzed.Again, this paper introduces the finite element analysis of suspension Bridges in Midas Civil theory and analysis method, explores a precise simulation of the suspension bridge in Midas Civil method, the finite element model for main cable saddle and saddle are simulated, Yangtze river bridge as a bridge to inch beach state and is used for calculation and analysis, the empty line and compares the design value, and design values coincide well with calculated value. Using the finite element model analyzed the saddle on the internal forces of the main cable and the influence of the linear; This article will also compares the analytical method and finite element method, the analytical algorithm and it is the result of finite element method coincide well.Finally, the paper analyzes the span, long line changes and the impact of temperature change on the empty cable shape, and get the three suitable for inch beach Yangtze river bridge the relation between the empty line state; This article has used the finite element method(fem) to investigate temperature on empty line condition the influence of the main cable shape, and high span across the bid and the two main cable saddle pre deviator value along with the change of temperature changes to the quadratic curve fitting; Main cable across the bid with high calculation by the rise of temperature, the cable saddle is pre deviator decreases with the increase of calculation temperature. |
