Study On Optimization Method Of Cable Force Of Extra-Dosed Cable-Stayed Bridge In Reasonable Finished State

With the development of the bridge technology in design and analysis,combination form of bridge becomes richer.Extra-dosed cable-stayed bridge,between continuous girder bridge and cable-stayed bridge,is a new type of them.As a transitional type bridge,it has not only the prestressed steel in continuous girder bridge but also the cable in the cable-stayed bridge.And it is widely accepted by various countries for its special structure performance and favorable economic benefit.However,the study on the type is not enough,which makes it necessary to more deeply cognize the bridge.Similar to cable-stayed bridge,design of extra-dosed cable-stayed bridge begins reasonable finished state so that how to reach this state is a key step in the whole process.Compared to the cable-stayed bridge,extra-dosed cable-stayed bridge is similar in the structure form but the mechanical characteristic,which leads to refer to the method of determining the reasonable finished state applying to cable-stayed bridge,instead of to copy absolutely.The prestress,along with the cable force in extra-dosed cable-stayed bridge,plays an important role in the finished state.Although some study on the comprehensive optimization of prestress and cable force appeared in some of the literature,the way of disposition about the prestress is dissatisfactory,with few texts on the internal relations between the prestress and the cable force effect.So what is mentioned above is just need to be discussed in this paper.In this paper,the development course of extra-dosed cable-stayed bridge is summarized,and the distinction with continuous girder bridge and cable-stayed bridge in structure and mechanical aspects also is contrasted in detail.At the same time,the method that how to reach the reasonable finished state is summarized with the evaluation about them in same view,which may provide some theoretical reference for the way being proposed later.As the appellation of the type,extra-dosed cable-stayed bridge is acceptable and reasonable from the perspective of mechanical and structural aspects,along with the demarcation about the type being introduced in the form of parameters.Ultimately,the form how to deal with the optimization problem gets the result of the influence matrix,when the way how to get the reasonable cable force is introduced.The particularity on the cable force optimization of the type has been definitely analyzed in this paper.In order to solve the problem about combination of cable force and prestress,it is originally advised to discretize the action of the prestress here.On the basis of the research before,compensation method has been put forward with its detailed process.The internal relations between the prestress and the cable force effect get answered because of establishment of the compensation matrix.In the end,the method is applied in longjinghe extra-large bridge,with the results of 27.4% discount of the cable force,which verifies the feasibility of the method.Importantly,some reference for the similar engineering project is expected in the paper.