Program Design And Application Study Of Construction Control For Long-span Suspension Bridge

As the traffic construction of China development in recent years, the number of long-span bridge that is building now or will be build in the future is larger and larger and it will become longer in the span and larger in the scope. As the most spanning ability type of bridge, suspension bridge puts the strong geometric nonlinear character up. Therefore, how to consider its influence reasonably and accurately in structural analysis has great theory significance and engineering value. This thesis has explored the calculation theory of cable curve for suspension bridge and geometric nonlinear analysis theory of suspension bridge and has put forward some applied calculation and analysis methods, which aiming at the characteristic of large suppleness and deformation and taking the Yangtse River Large Bridge of Highway in Yangluo Wuhan as the background.Based on segmental catenary theory, two kinds of common problem for the calculation of cable curve for suspension bridge is calculated and analyzed by iteration method. Principles which contain conservation of mass and unalterable unstressed length for main cable and mechanical balance condition for saddles are elaborated in details. The correction of unstressed length for main cable in saddles and calculation method of tangential point are considered at the same time. The increment stiffness equation of main saddle's pre-offset and vice saddle's pre-rotational-displacement is derived. At last, cable shape and internal force calculation on initial and final status of suspension bridge is realized by program.Geometric nonlinear analysis method and nonlinear equation solution method are compared and analyzed. According to the mechanical character and construction method of suspension bridge, the characteristic of main cable, sling, reinforced-beam, tower and saddle is simulated by using the finite element method (FEM). Geometric nonlinear analysis for combined structure which is composed of spar, catenary and beam element is realized by own compiled program. Based on the principle of multi-span catenary of main cable, action of tower to cable saddle is simulated as a nonlinear spring with beam-column effect considered while calculating tower stiffness; two formulas are established both for nonlinear horizontal stiffness and moment of bottom section of tower; deformation and mechanical rules of tower and main cable shape in its construction were analyzed. At last, geometric nonlinear problem in construction of reinforced-beam for suspension bridge is calculated and analyzed by program.Parameter sensitivity analysis is carried on according to engineering example. It contains mainly the influence of main cable shape when cable length, horizontal span, integral temperature, main beam weigh, earth curvature and main cable's elastic modulus are changed. Though calculation and comparation by program, the important parameters and their sensitivity are get through. At the same time, the former three parameters are analyzed by using the analytic method of parabola theory, and similar results with segmental catenary theory are obtained.