Studies On Mechanical Properties And Construction Control Of Self-anchored Suspension Bridge

Self-anchored suspension bridges have gained much popularity in recent decades for their esthetic appearance, favorable adaptability, economical performance and other notable advantages, especially in the construction of city bridges. Based on the design, model test and construction control of many self-anchored suspension bridges in this paper, universal laws have been found respectively in the point of qualitative and quantitative for mechanical properties and design parameters. Analytical method and efficient numerical approach of main cables have been proposed. Mechanical properties of self-anchored suspension bridges in construction control, optimization of cable force and tension process have been discussed. Based on stress-free status theory, parameter identification and errors reduction have been studied.(1) Based on nd theory, dimensionless equations of self-anchored suspension bridges have been deduced. Weight stiffness, parameters, and universal laws of mechanical properties have been studied, and gained applicable conditions of linear programs. Damp effect of stiffening girder for moment of girder and cable force, main cable sag effect of main cable force have been discussed and obtained analytical results.(2) The paper deduced analytical equations of main cable describing the configurations from initial state to final state. In this method, stress-free length of cables and displacement of saddle can be obtained without establishing finite element model.(3) Analytical element method of main cables in construction control was proposed in this paper. Provided that three-dimensional cables are particles system with tension stiffness, primary equilibrium equations of these particles could be established, and these equations could be solved by numerical method. Particles system equations, which reflecting the properties of cable structures, were solved by iterative method of force equilibrium. Changeable steps are applied automatically in the iterative calculation, so that the process is efficient and the results are convergent. Geometrical nonlinearity and material nonlinearity were both taken into account in this method. Compared with finite element method, no linear equations are obliged to solve in this method, so this method is more adaptable in calculating geometrical transformable structures, whereas the solutions of this kind of problems is often not convergent by finite element method. (4) Mechanical properties of self-anchored suspension bridges in construction control were studied in this paper. Weak interference principle of main cable displacements and near influence principle of hanger force are proposed and proved. These principles are proved universally correct in many cases.(5) Stress-free status theory is proved adaptable in the construction of self-anchored suspension bridges. Group theory was applied in the construction control of self-anchored suspension bridges. Defining tensioning process as transformation groups and studied the groups. Found the feasibility and efficiency of tension by 4 jacks and 8 jacks respectively. Alternate tension method has been obtained. In this method, hanger force increased equally during tensioning, and almost all bridges can fulfill system transformation by 8 jacks in 3 turns. Some bridges can be carried out tension in 2 turns.(6) Parameter identification and errors reduction in the construction control of self-anchored suspension bridges have been studied. Based on stress-free status theory, parameter identification and errors reduction have been studied. Considering the effect of stress-free length errors of main cables and hangers, weight errors of stiffening girders, errors of temperature, coefficients of design parameters influence has been provided. Proper errors of stress-free length of main cables and hangers, and the method by adjust hanger force and displacement of saddles.