Research On The Structural Force Redistriution For Double-Curved Arch Bridges Reforming

With the continuous development in Jiangsu Province local traffic network system reforming, the structural loading capability of current double-curved arch bridges can no longer adopt to the increasing transportation volume and the loading scale. The bridges have become the bottleneck in the traffic network reforming,to which both the engineering and the academic circles are paying much attention. These bridges were firstly built in 1964, then this kind of double-curved arch bridges were extensively applied in highway engineering with their special characteristics. Today, whether these bridges with distinct structure are able to continue to serve the road traffic in China depends on the loading potential of these bridges to be brought into full play. The road designers are in the position to dig the potentialities. They should increase the loading capacity and the traffic capacity by various reforming methods. In this thesis, a three-dimensional model for an existing double-curved arch bridge under rebuilding was established. Its loading capability was analysed with a large scale finite element software named Midas/civil. The structure system pre and after changing was studied. based on the indeterminate structural force redistribution theory, the structural loading ability and traffic level was improved by broadening and reforming the bridge. In the thesis, the basic reforming technologies of arch bridges are introduced Firstly briefly with the origin and development of the bridges. Secondly, the weak sections of the double-curved arch bridges under loads are analyzed. the idea for problem solving and reforming method is proposed. Thirdly, the rationality of finite element method used in bridge design is summarized .the software MIDAS/Civil is introduced, a spacial model for the Guihua double-curved arch bridge is established with the MIDAS/Civil software by two methods of broadening and reforming. the calculating result is drawn out. Finally, based on the analysis above and FE model ,the internal forces in the bridge pre and rebuilding under gravity and different orders of moving loads are obtained. It is concluded that the bridge loading ability can be improved significantly through different reforming schemes.