Cable Force Optimization For Cable-Stayed Bridge Based On Whole Process

Cable-stayed bridge got civil engineer's favor for it's beautiful formative and long span, the concrete cable-stayed bridge was greatly applied and developed in China for its low fabrication cost. Adjustability of initial tension made the structure design have larger vivid, but also an optimization problem was exiting. The influence of initial tension and prestressing force for beam stress is mutually, it must be considered synchronally. Reasonable finished internal force must be satisfied during optimization, safety of construction and application must be insure simultaneous, even bearing capacity could be considered. This text carries on a research for the above problem and completed a following work:(1)Introduced the research result about cable force optimization at home and abroad, summarized the basic theory in existence. A whole process cable force optimization theory include construction, finished, application even failure, not only aim at finished internal force.(2)According to influence matrix thought, least squares method was established by taking the setting cable force as design variable, taking reasonable finished internal force as object function, taking safety of structure during construction phase and equilibrium of cable force as constraint, which could synchronously optimize internal force of construction phase and finished phase. Geometry nonlinear problems of structure could be solved effectively by iterative computation. Through calculate example analysis, that method is practical and applied well.(3)According to least squares method, a multi-object optimum method was established by taking the setting cable force and prestress as design variable, taking reasonable finished internal force and dosage of prestress as object function, taking safety of structure during construction phase and equilibrium of cable force as constrain, which could coupling optimize cable force and prestress and synchronously optimize internal force of construction phase and finished phase. By taking a concrete cable stayed bridge as an example, a series of analysis parameter analysis such as uniformity of stipulation, target function selection...etc. were carried, and get the finial optimization result.(4)The analysis method and programmable thought for determining ultimate load-carrying capacity which could be taken material and geometrical nonlinearities into consideration was introduced in this thesis. A conclusion that different optimization methods taken puniness influence to ultimate states of cable stayed bridge was made by analyze with existing program.