Analysis Of Mechanical Performance Of Single-tower Composite Girder Cable-stayed Bridge During Construction Process

The construction process of single-tower composite girder cable-stayed bridge is complicated,which involves many key problems such as reasonable completion state determination,cable force optimization,Stress-free configuration calculation,internal force control and local stress analysis.Therefore,it is necessary to analyze and study the mechanical performance of the whole construction process.Taking Kaixiahe Bridge as the engineering background,this paper studies the cable force optimization,concrete time-varying effect and structural parameter analy sis and identification of cable-stayed bridge based on the finite element software Midas Civil.ANSYS software is used to calculate the cable and beam anchoring structure.The research results are as follows:1.The finite element model of Kaixiahe Bridge is established by using Midas Civil finite element analysis software.The calculation formula of cable length was derived,and the stress-free cable length under reasonable bridge completion was obtained based on the minimum bending energy method.The cable force of the whole bridge was optimized and adjusted before the paving of the second phase.2.The differences of bridging profile,manufacturing profile,installation profile and design profile are explained in detail.On the basis of tangential displacement method and zero displacement method,the solutions of manufacturing profile and installation profile are compared and analyzed.The fabrication line,installation-line,stress-free Angle and stress-free installation of the main girder of Kaixiahe Bridge are solved.3.The internal forces of the main tower and composite beams during the whole construction process,as well as the effects of concrete shrinkage and creep and loading age on the forces of the main tower,girder and cable-stayed cable are studied.The static and fatigue properties of cable-beam anchoring structure were numerically simulated.The influence of stiffener and anchor plate size on the mechanical properties of cable-beam anchoring structure was studied.4.Based on the principle of least square method,the sensitivity analysis and correction of the structural parameters of Kaixiahe Bridge during the construction process are carried out.Based on the grey prediction principle,the theoretical elevation of the subsequent beam sections can be deduced from the measured elevation of the existing beam sections.The results show that the grey prediction depends on the development trend of the measured data,so more measured data are needed to predict the grey prediction accurately,and the finite element model with the modified least square method is more accurate.