Improved Calculation Method Of Main Cable Strand Erection Of Three-Tower Self-Anchored Suspension Bridge

With the massive construction and the increasing span of three-tower self-anchored suspension bridge,people put forward higher requirements for construction control,whose effect directly affects the geometric shape and internal force of the bridge.However,there are some deviations between the hypothesis and the reality of the existing construction control calculation methods when dealing with some detail problems,which affects the accuracy and effectiveness of structural calculation.In order to improve the efficiency of calculation of cable system of suspension bridge construction control,this paper takes a three-tower self-anchored suspension bridge as an engineering background,and improves the construction control calculation method of main cable strand erection.Firstly,the differences between the theories and formulas of elastic and inelastic catenary are pointed out,and the applicable scope of the theory of inelastic catenary is given through comparative analysis.Based on the elastic catenary theory,a set of calculation method of saddle pre-deviation suitable for the three-tower self-anchored suspension bridge and the improved calculation method of cable strand geometric shape considering the section of saddle tangent points are proposed.The solving process of horizontal force is optimized,and the calculation efficiency of cable-strand shape is improved.And the MATLAB program of cable-strand shape calculation is compiled.Secondly,based on the theory of elastic catenary,the effect formulas of cable saddle predeviation,mid-span elevation of cable strand and coordinates of cable clamp are established.Taking the suspension bridge as the engineering background,the control calculation of the main cable stress-free length,cable saddle pre-deviation,datum strands geometric shape,tension of cable strand of anchor span and coordinates of cable clamp are carried out by using the improved calculation program of cable strand shape compiled in this paper,through the influence analysis of parameters,the example shows that the effect formulas in this paper has high accuracy.Finally,the temperature field of the main cable of the suspension bridge is studied by using finite element method,and the calculation method of the average temperature of the cross section of the main cable suitable for the construction control of the cable system is proposed.The results show that the maximum error of the method is less than 1 ?,which meets the requirements of the construction control accuracy.By comparing and analyzing the temperature field of cable/strand with five diameters,and the reasonable diameter limit for calculating the average temperature of the cross section of the main cable by finite element method is proposed.The results show that the average temperature of the cross section of the main cable with diameter greater than 400 mm needs to be calculated by surface temperature measuring points combined with finite element method.The calculation example shows that the improved calculation method of main cable strand erection of suspension bridge in this paper is efficient and practical,which provides an important reference for the construction control calculation of similar projects.