The Nonlinear Mixed-integer Parameters Optimization Of The Concrete Tied Arch Bridge

Along with the rapid development of China’s bridge construction, concrete tied arch bridge has been applied and developed more and more widely for its beautiful shape, light structure, small building height, large span capacity as well as the good adaptability to the topographic and geologic conditions.The traditional design of concrete tied arch bridge is time-consuming and cumbersome and the design solution depends on the designer’s level, it is impossible to get the optimal and auto results. Moreover, the scholars at home and abroad have done lots of research and practical results have been got, but most studies separately focus on the suspender force, reasonable arch axis and so on. There are few of globally optimization designs use the form of arch axis, arch rib section size, tied root number and suspender area as relevant parameters.Combining with the current research results about tied arch bridge both at home and abroad and on the background of a built tied arch bridge with suspended roadway, a global optimization design by finite element structural analysis program and optimization program has been done in this paper. The main research contents are as follows:1. Analyze the design parameters about the rigid tie rod rigid arch based on theories, such as arch rib section size, arch axis coefficient, rise-span ratio, etc.2. The principle of the finite element analysis program is reviewed, the general calculation procedure for tied arch bridge is compiled, and strong support is provided for the re-analysis in the optimization iteration. Moreover, comparing with the results of Midas Civil, the correctness of the finite element analysis program is verified by the finite element model of the actual example.3. The Mixed-Integer Sequential Quadratic Programming is expatiated, and the original optimization program is reconstruct and the correctness and effectiveness of it is verified by typical examples.4. Puts forward and develops the optimization mathematical model, which uses the total cost of rib concrete, tied root, and suspender as the objective function, uses arch axis coefficient, arch rib section size, tied root number and suspender area as design parameters, uses the stress and displacement of arch rid as constraints, compiles the corresponding optimization program and does global optimization design.5. The correctness of optimization results are verified by the finite element software Midas Civil and the optimization results under different conditions are analyzed. At last the relevant conclusions are received.