Research On Concept Design Of Beam-Arch Association Bridges

Beam-arch association bridges combining the exquisite appearance and reasonable mechanical characteristics have been developing rapidly in the modern big span Bridges. However, the engineering staff often carry on the design according to specification and terms because of busy time,that lead to lack of overall confidence of bridge design concept.Concept design of the beam-arch association bridges is analyzed. First, the design concept of bridge is summarized,and parameters that affect the load distribution ratio between beam and arch are discussed. Second, problems about target force and target shape of beam-arch association bridges' cables are discussed.The last, The initial tension of finite element model in different analysis stage is obtained with target force algorithm in practice. The contents and conclusions are as follows:(1) The whole system of bridge conceptual design with definition,principle and procedures isresearched. nalysis of mechanical characteristics of beam bridges and arch bridges isstudied. The form classification,structure analysis and construction method of beam-arch association bridges are also summarized. The choice of parameters is discussed and construction requirements needed to be payed attention during the design.At last, with a simple beam-arch association structure model analysis,the influence on the load distribution ratio between beam and arch by the different stiffness and rise to span ratio of beam-arch association bridges.(2) Firstly,mechanical characteristics of single cable without prestress is analyzed.Secondly,an algorithm of target force and target shape with prestress is discussed theoretically.Thirdly, the numerical relationship of between target force and initial tension was solved in the case of prestressed cable structure., numerical relationship of between target force and initial tension is then solved in the case of prestressed beam-arch association structure. Finally, based on the theory, The results of cases proved its correctness.(3) The initial tension in two construction stage of practical engineering structure was obtained with the algorithm of target force.The result proved the correctness of the theory.The above results for deeper understanding the concept design of beam-arch association bridges provides theory basis.