Make Sure The Pc Cable-stayed Bridge Is Reasonable To Bridge The State Of Cable Force And Prestressed Coupling Optimization Method

Generally, design of bridge should obey four principles, which are safe, reasonable, economical,and artistic.During the process of designing, once structure form and main dimensions are decided, the contradictory between safety of structure and economical bridge has to be solved, this contradictory shows in the form of controlling internal force state of the structure effectively and minimizing the expense on materials which used for balancing the internal force.Cable-stayed bridge is statically indeterminate structure, top part of bridge are consisted of beam, tower and cable,the tension force in cables will largely affect internal force distribution in structure, especially for long-span cable-stayed bridge, cable force is critical component to control the state of internal force of the whole bridge.So generally, the design of cable-stayed bridge is begin with determining finished dead state of bridge, this is the first problem to be solved.In terms of determining completion state of bridge, many researchers from home and abroad have worked out many methods, however, each method has its own emphasis point and limitation.This paper includes research achievements from former researchers, and is aimed at the problem of how to deciding finished dead state of bridge, and also has completed the following work:1 Development situation of PC cable-stayed bridge,its characteristics,the trend of development and the situation of deciding finished dead state of bridge,and also the applicable scope of each method are summarized2 Refer to the methods created by former researchers,another method is brought up for determining finished dead state of bridge--cable force and prestress coupling optimization,mathematic optimal model is built, and some technical treatment methods during building model is introduced.3 Method of solving the model is introduced--improved constrained variable metric,improvement measures is discussed in the paper, some extension has been done on function of original program of the method,sevaral numerical examples have been proceeded to prove the correctness of program4 After using this method on a typical long-span PC cable-stayed bridge, it is found that optimized cable force is reasonably distributed, and also the stress in beam and tower,less prestressed reinforcement is needed in main beam for satisfying requirement of usage, the purpose of optimization is achieved. These have proved this method can be used for determining finished dead state of PC cable-stayed bridge, it is effective and applicable.